Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

ACVD Exam > Cutaneous Neoplasia and Paraneoplastic Syndromes > Flashcards

Cutaneous Neoplasia and Paraneoplastic Syndromes Flashcards

1
Q

What does interphase consist of?

A

G1: cell growth
S: DNA replication
G2: preparation for mitosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the common places where the cell cycle becomes unregulated?

A

Loss of normal checkpoints
Overexpression of growth factors
Loss of signal to die
Loss of repair mechanisms in S phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are two major proteins that regulate the cell cycle?

A

cyclins
cyclin-dependent kinases (CDKs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How can some cancers use telomerase?

A

Some cancer cells utilize telomerase to add telomeric sections to the ends of DNA during DNA replication, allowing these cancer cells to live and divide much longer than other somatic cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is p27?

A

a protein thought to maintain cells in G0 and which may be decreased in cancers like squamous cell carcinoma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the most common phase of the cell cycle for veterinary chemotherapeutic agents to work on?

A

S phase (DNA replication)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What stage of the cell cycle do antimetabolite chemotherapeutics work on?

A

S

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What stage of the cell cycle do alkylating agent chemotherapeutics work on?

A

S

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What stage of the cell cycle do cross-linking agent chemotherapeutics work on?

A

S

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What stage of the cell cycle do topoisomerase inhibitor chemotherapeutics work on?

A

S

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What stage of the cell cycle do antimicrotubule agent chemotherapeutics work on?

A

M

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What stage of the cell cycle do signal transduction inhibitor chemotherapeutics work on?

A

the level of signal transduction that starts the cell cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

When are cells most resistant to radiation therapy?

A

in S phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

In addition to making the tumor smaller, what can be a benefit of debulking surgery?

A

may stimulate cells to divide –>
may force them into a phase of the cell cycle more susceptible to other therapies.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is a proto-oncogene?

A

are a group of normal genes in cells which can cause cells to become cancerous when the genes are mutated
- normally help cells grow and
divide or stay alive
Usually produce proteins that
- stimulate cell division
- inhibit cell differentiation
- halt cell death

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is an oncogene?

A

what a proto-oncogene is called once it has mutated
mutations are usually dominant and increase the level of activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is c-kit?

A

a proto-oncogene that encodes the receptor tyrosine kinase protein
- aka KIT, CD117, or mast/stem cell growth factor receptor (SCFR)
activating mutations lead to cancer
not restricted to mast cell tumors but is a prognostic indicator in them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the role of tyrosine kinase protein (KIT)?

A

a transmembrane cytokine receptor
on the surface of hematopoietic stem cells, interstitial cells, melanocytes, and mast cells
binds to stem cell factor (steel factor)
- forms a dimer
- activates its intrinsic activity
- leads to phosphorylation
- activation of signal cascades
promotes cell survival, proliferation, and differentiation
also involved in fibronectin adhesion, chemotaxis, and degranulation of mast cell tumors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is c-myc?

A

a proto-oncogene
encodes a transcription factor that regulates the cell cycle
Aberrant expression c-myc is present in many feline and canine cutaneous tumors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are tumor suppressor genes?

A

normal genes that slow down cell division or tell cells to die at the right time
- ex TP53 that encodes p53
- ex retinoblastoma protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is TP53?

A

a tumor suppressor gene
encodes for the p53 protein
- most frequently mutated
protein in all human cancers
regulates apoptosis in response to genotoxic or cellular stress

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is retinoblastoma protein (pRB)?

A

a tumor suppressor protein
- normally inhibits cell cycle progression until a cell is ready to divide
- papilloma E7 binds to and inhibits it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are DNA repair genes?

A

normal genes that help fix mistakes made when the cell copies its DNA in cell division
If they can’t fix the cell, they trigger cell death
- ex BRCA in some breast cancers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are 13 hallmarks of cancer?

A

(1) Genomic instability and mutation
(2) Replicative immortality
(3) Insensitivity to growth suppressive signals
(4) Ability to evade programmed cell death
(5) Reprogrammed energy metabolism
(6) Sustained angiogenesis
(7) Immune destruction evasion
(8) Tumor-promoting inflammation
(9) Self-sufficiency in growth signals/replicative immortality
(10) Tissue invasion and metastasis
(11) Phenotypic plasticity and disrupted differentiation
(12) Non-mutational epigenetic reprogramming
(13) The microbiome changes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How can energy metabolism differ between normal and neoplastic cells?

A

normal cells use oxygen to process glucose and produce energy
neoplastic cells can switch to aerobic glycolysis even in the presence of oxygen
- less efficient but faster
- makes several intermediate pecursors
other cancer cells can use lactate as main energy source

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are the most important inflammatory mechanisms that are corrupted by tumors?

A

NF-kappaB and inflammasome signaling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What mediates tumor tissue invasion and metastasis?

A

E-cadherin
integrins
other adhesion molecules
production of matrix-degrading proteases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are the paradigms of cancer metastasis?

A

Traditional: late-stage tumor shedding, after the tumor is of significant size
Parallel progression model: cells
disseminate from tumors early, possibly even before malignant conversion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the metastatic cascade?

A

(1) Invasion and migration
(2) Angiogenesis and intravasation
(3) Survival in the circulation and attachment to the endothelium
(4) Extravasation and colonization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is considered the differentiating step between pre-cancerous neoplasia and malignant cancer?

A

Invasion through the basement membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

How can angiogenesis facilitate metastasis?

A

enables the delivery of nutrients and oxygen
facilitates the removal of waste
immature new vessels are more permeable
- facilitating tumor intravasation
- enables transport to distant sites
- via vascular and lymph systems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What destroys most metastatic cells before they become distant tumors?

A

hemodynamic shear forces
red blood cell collisions
immune stresses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

How do metastatic cells extravasate?

A

physical occlusion
- the cells get lodged in small microvasculature
adhesion after rolling
- via binding with E-selectin, P-selectin, ICAM-1, or VCAM-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What are metastatic niches?

A

contain cell types and an extracellular matrix compatible for tumor cell survival and growth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is the Cancer Immunosurveillance theory?

A

is that the immune system works to identify normal vs. transformed cells and constrain tumor growth
therefore, suppressing the immune system would increase the risk of neoplastic growth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

How is cyclosporine is believed to be associated with the development of neoplasia?

A
  1. Inhibiting cytotoxic T cell-mediated anti-tumor immune surveillance
  2. Direct cellular effects (humans): morphological alterations, increased cell motility, and anchorage
    independent (invasive) growth.
  3. Mechanisms have not been elucidated entirely
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What is the evidence for cyclosporine-based risk for neoplasia in small animals?

A
  1. An increased risk of neoplasia after feline renal transplantation and cyclosporine-based
    immunosuppression has been reported
  2. A dog developed multicentric lymphoma after being on cyclosporine for anal furunculosis for 4 weeks
  3. A dog developed multiple cutaneous hamartomas and squamous cell carcinoma in situ after being on long-term immunosuppressive therapy with prednisone and cyclosporine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What is the mechanism by which Apoquel is associated with the development of neoplasia?

A

by inhibiting JAK-1 receptor mediated signal transduction
results in an inhibition of cytokines (IL-2, IL-4)
subsequently reduce stimulation of cells of the innate tumor immunosurveillance system (gamma delta T-cells, NK cells)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

How can cyclosporine be protective against some forms of cancer?

A

activation of p53 (e.g., bladder cancer, colorectal cancer, glioblastoma, and leukemia)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What is the theory by which oclacitinib may be part of combination therapeutic protocols with chemotherapy for certain types of canine cancers?

A

aberrant JAK / STAT signaling within hematologic and solid tumors can be a driver of tumor growth through effects on the local microenvironment, enhancing angiogenesis, immune suppression, and others

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What is the evidence against immunosuppressive drugs causing neoplasia in dogs?

A
  1. There has been no increased prevalence of canine neoplasia reported in any cyclosporine published clinical trials compared to the general dog population.
  2. A retrospective study did not find that cyclosporine treatment for canine atopic dermatitis was a significant risk factor for cutaneous lymphoma.
  3. A retrospective study found no association between oclacitinib and the development of cutaneous tumors (benign or malignant) in dogs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What are the 4 ways to classify malignant tumors?

A

(1) broadly, by tissue, organ, and system
(2) by specific type
(3) histologic grade
(4) by spread (staging)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What are solid neoplasms subdivided into?

A

(1) Tumors of epithelial origin
(2) Tumors of mesenchymal origin
(3) Tumors of the blood (= leukemia)
(4) Tumors of lymphoid origin (= lymphoma)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Where do tumors of epithelial originate from?

A

epidermis, hair follicle, nailbed, or skin glands (sebaceous, apocrine, or eccrine glands)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What are carcinosarcomas?

A

rare neoplasms composed of admixed malignant epithelial and mesenchymal elements that metastasize together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What are the major mesenchymal cell types?

A

fibroblasts, mesothelium, endothelium, adipocytes, myoblasts, chondroblasts, and osteoblasts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What is the most common malignant neoplasms in cats?

A

tumors of mesenchymal origin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What are the common neoplasms of epithelia origin?

A

squamous cell carcinoma
apocrine/sebaceous gland tumors
tumors of hair follicles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What are the common mesenchymal tumors (related to dermatology)?

A

adipose tumors (lipoma/sarcoma)
muscle tumors (leiomyoma/sarcoma, rhabdomyoma/sarcoma)
blood and lymphatic vessel tumors (hemangioma/sarcoma, glomus tumors, lymphangioma/sarcoma)
peripheral nerve tumors
tumors of histiocytic or mastocytic origin
connective tissue tumors (myxoma/sarcoma, fibroma/sarcoma, hemangiopericytoma, sarcoid)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

What is tumor grading based on?

A

combination of cytologic features (e.g., extent of cellular differentiation and dysplasia) and morphological-structural observations (e.g., mitotic count, necrosis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What does increasing grade tend to be correlated with?

A

poorer or lack of differentiation
increasing grade correlates with more aggressive anticipated behavior, metastatic potential, and/ or potential for recurrence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What does tumor stage refer to?

A

extent of spread throughout the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

What is the TNM Classification of Malignant Tumors?

A

a widely used system for scoring tumor spread
size/extent of the primary tumor (T)
degree of spread to the LNs (N)
presence of distant metastases (M)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

How do sarcomas tend to metastasize?

A

through blood
most commonly go to lungs
initial staging should include chest radiographs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

How do carcinomas tend to metastasize?

A

tend to metastasize through blood and lymphatics
regional lymph nodes, lungs, liver, and/or spleen
staging includes aspirating the regional lymph node, chest radiographs, and abdominal ultrasound

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

What are sarcomas?

A

mesenchymal cancers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

What are carcinomas?

A

epithelial cancers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

How do round cell tumors tend to metastasize?

A

through the lymphatic systems
regional lymph nodes, liver and spleen
staging involves regional lymph node aspiration +/- abdominal ultrasound with liver/spleen aspiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

What are physical factors involved in the development of skin cancer in dogs and cats?

A

ionizing radiation
- squamous cell carcinoma
thermal injury
trauma
- fibrosarc or lymphoma (cats)
chemical injury

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

What are papilloma viruses associated with the development of in cats?

A

Bowenoid in situ carcinoma
squamous cell carcinoma
viral plaques
feline fibropapillomas (sarcoids)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

What are papilloma viruses associated with the development of in dogs?

A

development of squamous cell carcinoma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

What neoplasia is bilateral ischemic necrosis of the hindpaws associated with in cats?

A

May be associated with multicentric follicular lymphoma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

What neoplasms is feline skin fragility syndrome associated with?

A

adrenal and other abdominal carcinomas
multicentric lymphoma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

What common immunocytochemical stains are used for T cell neoplasias?

A

CD3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

What common immunocytochemical stains are used for B cell neoplasias?

A

CD79a and CD20

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

What common immunocytochemical stains are used for epithelial neoplasias?

A

cytokeratin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

What common immunocytochemical stains are used for mesenchymal cells neoplasias?

A

vimentin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

What common immunocytochemical stains are used for melanocytic neoplasias?

A

Melan A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

What are the cell grouping of epithelial tumors on cytology?

A

Intercellular junctions between
cells → cells are arranged in cohesive sheets or clusters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

What are the morphologic features of epithelial tumors on cytology?

A

Round*, cuboidal, columnar, or polygonal

Cytoplasmic borders of individual cells are usually distinct.
- Tend to lose intercellular junctions/appear as discrete
round cells when poorly differentiated

If glandular tissue, may have
cytoplasmic vacuoles or
produce a cytoplasmic
product that displaces the nucleus.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

What are the morphologic features of mesencymal tumors on cytology?

A

Spindle, stellate, or oval

Cytoplasmic margins are indistinct

Often embedded in ECM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

What are the cell grouping of epithelial tumors on cytology?

A

No intercellular junctions → arranged individually or in non-cohesive aggregates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

What is the degree of exfoliation of epithelial tumors?

A

Exfoliate well (typically)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

What is the degree of exfoliation of mesenchymal tumors?

A

Exfoliate poorly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

What are the cell grouping of round cell tumors on cytology?

A

Individualized in a monolayer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

What is the degree of exfoliation of round cell tumors?

A

Exfoliate well

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

What are the cutaneous round cell tumors?

A

Mast cell tumor
histiocytic tumors
plasma cell tumors
transmissible venereal tumor
lymphoma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

What is the appearance of melanocytic tumors on cytology?

A

mesenchymal but can adopt the appearance of epithelial, mesenchymal, or round cells
may or may not have intracytoplasmic pigmentation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

What are the most common histochemical stains for small animal cutaneous tumors?

A

Toluidine blue and Giemsa
– used for mast cell tumors
Fontana Masson
– used for melanomas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

What are the common IHCs used in histopathology for hemangiosarcomas?

A

factor VIII related antigen
- von Willebrand factor
claudin 5
CD31
laminin
type IV collagen
*= endothelial origin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

What are the common IHCs used in histopathology for melanomas?

A

usually a “cocktail”
melan-A
PNL2
TRP-1 and TRP-2
+/- S100

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

What are the common IHCs used in histopathology for smooth muscle tumors?

A

smooth muscle actin
desmin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

What are the common IHCs used in histopathology for skeletal muscle tumors?

A

myogenin D
sarcomeric actin
desmin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
84
Q

What are the common IHCs used in histopathology for mast cell tumors?

A

CD1117/c-kit
*can be helpful in prognostication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
85
Q

What are the common IHCs used in histopathology for plasma cell tumors?

A

MM-1/interferon regulatory factor-4 (MUM1/IRF4)?

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
86
Q

What are the common IHCs used in histopathology for T cell lymphoma?

A

CD3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
87
Q

What are the common IHCs used in histopathology for B cell lymphoma?

A

CD79a
CD20
PAX5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
88
Q

What are the common IHCs used in histopathology for neuroendocrine tumors?

A

chromogranin A
synaptophysin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
89
Q

What are the common IHCs used in histopathology for histiocytomas?

A

CD18
CD204
IBA-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
90
Q

What is a Polymerase Chain Reaction for Antigen Receptor Rearrangement (PARR) assay?

A

separates DNA by size to evaluate for clonal populations of B- and T-cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
91
Q

How does PARR work?

A

If a cell becomes neoplastic, it no longer responds to growth controls –> it undergoes unlimited expansion
- the Ig or T-cell receptor genes in that population (depending on whether it is a B-cell or T-cell lymphoma) will be a single size
- reactive process should have multiple, different-sized, T-cell receptor and Ig genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
92
Q

What are the applications of PARR?

A

*only in lymphoid cells
establish clonality in a sample that is cytologically or histologically ambiguous
compare two neoplasms arising at different times to determine whether they have the same clonal origin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
93
Q

How does flow cytometry work?

A

*most easily applied to fluid
- can also be cells in buffer method for counting/evaluating cells
cell suspension is passed through a detection laser
rapidly and simultaneously evaluates cellular granularity/size
input into a computer to analyze cell type

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
94
Q

What are ablative therapies?

A

involves the physical removal of tumor tissue in bulk
- Conventional surgery
- Hyperthermia
- Cryotherapy
- Laser ablation
- Surgical diathermy
- Vascular or tumor ligation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
95
Q

What are the lasers used in veterinary dermatology?

A

carbon dioxide
neodymium-doped yttrium aluminium garnet (Nd:YAG)
diode lasers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
96
Q

What are cytotoxic therapies?

A

Chemotherapy
Photodynamic therapy (PDT)
Electrochemotherapy
Radiation therapy (RT)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
97
Q

What is oncologic chemotherapy?

A

the treatment of cancerous cells through cytotoxic medications
- typically prevent tumor cells from multiplying by interfering with their ability to replicate DNA
- can be utilized systemically or locally

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
98
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
99
Q

How does photodynamic therapy work?

A

involves the use of light of appropriate activating wavelengths, oxygen, and a photosensitizer
- accumulates within a tumor
When excited, the photosensitizer reacts with molecular oxygen to create ROS that cause vascular stasis and necrosis, membrane damage, apoptosis, and inflammatory cascades

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
100
Q

How does electrochemotherapy work?

A

involves electric pulses that cause reversible permeabilization of cell membranes, enabling entry of chemotherapeutic drugs or immunotherapies into cells
- electroporation
The primary indication is incompletely excised cutaneous and subcutaneous tumors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
101
Q

How does radiation therapy work?

A

involves the absorption of ionizing radiation into cells –> creates highly reactive free radicals that result in biologic damage that may kill the cell or render it incapable of reproducing
This is a treatment modality for solid tumors in animals
- soft tissue sarcomas
- mast cell tumors
- cutaneous lymphoma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
102
Q

What is fractionated RT?

A

involves the dividing of total RT dose into smaller doses (fractions) to cause less tissue injury and in some cases improve efficacy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
103
Q

What is brachytherapy?

A

a type of RT that utilizes radioactive implants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
104
Q

What are the adverse effects of radiation therapy on normal tissue?

A

acute
- mucositis
- erythema
- alopecia (temporary or permanent)
- desquamation
- lymphedema
- changes in pigmentation
- swelling
late (severe)
- rare, include fibrosis/necrosis
consequential
delayed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
105
Q

What is radiation recall?

A

poorly understood phenomenon wherein animals treated with chemotherapy after a course of RT develop a return of the radiation side effects like mucositis or skin desquamation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
106
Q

What is the percentage of malignant tumors in cats?

A

percentage of malignant skin tumors is higher in cats than dogs (70-82%)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
107
Q

What are the top skin tumors in dogs?

A

mast cell tumor (16.8%)
lipoma (8.5%)
histiocytoma (8.4%)
perianal gland adenoma (7.8%)
sebaceous hyperplasia/adenoma (6.5%)
squamous cell carcinoma (6%)
melanoma (5.6%)
fibrosarcoma (5.4%)
basal cell tumor (5%)
malignant peripheral nerve sheath tumor (4.3%)
papilloma (2.8%)
sweat gland adenocarcinoma (1.1%)
sebaceous adenocarcinoma (0.5%)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
108
Q

What are the top skin tumors in cats?

A

Basal cell tumors, mast cell tumors, squamous cell carcinoma, and fibrosarcoma account for ~70% of all feline skin tumors
basal cell tumor (23%)
mast cell tumor (16.5%)
fibrosarcoma (17.9%)
squamous cell carcinoma (10.4%)
miscellaneous (10.1%)
apocrine adenoma (3.4%)
lipoma (3.3%)
hemangiosarcoma (2.9%)
sebaceous adenoma (2.8%)
fibroma (2.7%)
hemangioma (1.7%)
melanoma (1.7%)
malignant fibrous histiocytoma (0.7%)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
109
Q

What are the differential diagnoses of plasma cells causing cutaneous tumor(s) in dogs and cats?

A

Solitary extramedullary cutaneous plasmacytoma
- 95%
Cutaneous plasmacytosis
- dogs only
Cutaneous metastasis from multiple myeloma
- <1% overall but up to 30% of cats with multiple myeloma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
110
Q

What are cutaneous plasma cell tumors?

A

found in both the dog and cat
part of a group of diseases called myeloma-related disorders
caused by clonal neoplastic populations of plasma cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
111
Q

What are myeloma-related disorders?

A

cutaneous plasma cell tumors
multiple myeloma
non-cutaneous extramedullary plasmacytoma
macroglobulinemia
solitary osseous plasmacytoma
cutaneous plasmacytosis
plasma cell leukemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
112
Q

When is staging important for cutaneous plasma cell tumors?

A

most important in cases of cutaneous plasmacytosis and multiple myeloma
- relatively high metastatic rates
less important for cutaneous or oral solitary extramedullary plasmacytomas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
113
Q

What can be found in the serum or urine of animals with cutaneous plasmacytosis and multiple myeloma?

A

M component

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
114
Q

Where do extramedullary solitary plasmacytomas tend to occur in dogs?

A

mostly cutaneous (86%)
- limbs and head
oral cavity/lip membranes (9%)
gastrointestinal tract (4%)
other: spleen, genitalia, eye, third eyelid, liver, larynx, and trachea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
115
Q

Do extramedullary solitary plasmacytomas metastasize in dogs?

A

typically benign
tumors may develop nodal or distant metastases (2% cases), new cutaneous plasmacytomas at sites distant from the primary tumor (<2% cases), or monoclonal gammopathy or plasma cell leukemia.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
116
Q

What is the typical signalment of a dog with an extramedullary solitary plasmacytomas?

A

Median age is 9-10 years
breeds may be predisposed: Airedale terrier, boxer, cocker spaniel (English and American), German shepherd, West Highland white terrier, Yorkshire terrier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
117
Q

What is the treatment of extramedullary solitary plasmacytomas in dogs?

A

Conservative surgical excision is curative in most cases
Local recurrence rate 5%
Anecdotal success with cryotherapy, electrocautery ablation, and carbon dioxide laser ablation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
118
Q

What are the clinical signs of extramedullary solitary plasmacytomas?

A

Solitary, smooth, raised pink, variably alopecic, up to 10cm diameter
Typically, no related systemic signs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
119
Q

What is the behavior of extramedullary solitary plasmacytomas in cats?

A

mostly cutaneous but can also occur elsewhere
May be benign but may also progress to systemic myeloma-related diseases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
120
Q

What is cutaneous plasmacytosis?

A

occurs in dogs only
Biologically aggressive
- outcomes similar to multiple myeloma
- Associated with
lymph node or abdominal viscera involvement in approximately 30% of cases
- May have monoclonal gammopathy
has multiple extramedullary cutaneous plasmacytomas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
121
Q

What is the treatment of cutaneous plasmacytosis in dogs?

A

Systemic chemotherapy is indicated: melphalan (treatment of choice), lomustine, prednisone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
122
Q

What is the M component?

A

accumulation of a single type of a whole immunoglobulin molecule or an immunoglobulin component
(like the Bence Jones protein)
- seen in multiple myeloma
- usually IgA or IgG in dogs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
123
Q
A

clinical signs of multiple myeloma are typically associated with the infiltration of bone or organs with neoplastic plasma cells
- bone disease
- bleeding diathesis
- hyperviscosity syndrome
- cytopenias secondary to myelophtisis
- cardiac failure
- hypercalcemia
- immunodeficiency/infections
- renal disease
- cryoglobulinemia
*usually bone marrow in dogs
*usually abdominal in cats
- occasional familial association

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
124
Q

What are some cutaneous manifestations of cryoglobulinemia?

A

particularly on the extremities
erythema
purpura
ulcerations
punched out necrosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
125
Q

What neoplasia is cryoglobulinemia seen with?

A

Multiple myeloma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
126
Q

What is the treatment of multiple myeloma in dogs?

A

aimed at reducing tumor cell mass and ameliorating the secondary systemic side effects they elicit
- melphalan (TOC)
- cyclophosphamide
- lomustine
- prednisone
- chlorambucil
Prognosis for long-term survival is generally good with chemotherapy (median survival time 540 days)
- complete remission typically doesn’t occur

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
127
Q

What is the treatment of multiple myeloma in cats?

A

Treatment goals and options are similar to dogs, though melphalan is used less commonly
Prognosis for long-term survival is poorer than dogs (median survival time 4-13 months)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
128
Q

What are differential diagnoses for mast cell causing cutaneous tumors in dogs and cats?

A
  1. Mast cell tumors
  2. Urticaria pigmentosa
  3. Diffuse cutaneous mastocytosis
  4. Systemic mastocytosis with cutaneous involvement
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
129
Q

What is the most common type of cutaneous tumor in dogs?

A

Cutaneous mast cell tumors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
130
Q

What is the most common malignant tumor in dogs?

A

Cutaneous mast cell tumors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
131
Q

How do cat cutaneous mast cell tumors behave?

A

quite different than their canine counterparts and in general have a benign behavior

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
132
Q

In which animals have spontaneously regressing MCTs been reported?

A

young animals: cats, pigs, horses, humans, and one dog

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
133
Q

What mediators are ultimately responsible for many of the clinical signs associated with MCTs?

A

Granule contents
heparin, chondroitin sulfate, biogenic amines (histamine), preformed tumor necrosis factor alpha (TNF-alpha), proteases (in the skin, primarily chymase and tryptase), acid hydrolases, cathepsin G, carboxypeptidase, and others

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
134
Q

What do alterations in the oncogene encoding the KIT receptor (c-kit) do for for MCTs in dogs?

A

associated with 25-30% of intermediate- and high-grade MCTs and are linked to increased risk of local recurrence, metastasis, and tumor-related death

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
135
Q

Why are tyrosine kinase inhibitors used for treatment of MCTs?

A

Stem cell factor is a growth factor which binds to the tyrosine kinase receptor KIT (c-kit) on mast cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
136
Q

Where are mast cell tumors typically found in dogs?

A

most commonly in the dermal and subcutaneous tissues
usually solitary, but they may be multiple (11-14% affected dogs)
frequently trunk and perineal region (50%), limbs (40%), and head and neck (10%)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
137
Q

What is the etiology of mast cell tumors?

A

Etiology is unknown
Chronic inflammation may play a role
likely a role of genetic changes
- may involve alterations in p53
- expression of cyclin-dependent kinase inhibitors (p21, p27)
- estrogen and progesterone receptor expression and localization
- c-kit mutations
- others

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
138
Q

What mutation can lead to survival, proliferation, and oncogenic transformation in canine MCTs?

A

A gain of function mutation in exon 8 or 11 of c-kit
- can develop without a c-kit mutation
is a negative prognostic indicator

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
139
Q

What is the signalment of typical dogs with MCTs?

A

Mean age of dogs is 8-9 years
No sex predilection
Certain breeds may be predisposed: bulldog descendants (boxer, Boston terrier, English bulldog, pug), Labrador retriever, golden retriever, cocker spaniel, schnauzer, Staffordshire bull terrier, beagle, Rhodesian ridgeback, Weimaraner, and Chinese shar pei

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
140
Q

Which breed of dog is most likely to develop less aggressive mast cell tumors?

A

bulldog descendants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
141
Q

Which breed of dog is most likely to develop more aggressive mast cell tumors?

A

shar peis
and at a younger age
can have multiple on the extremities that create gross distension and deformity of the legs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
142
Q

What is the typical clinical appearance of well-differentiated cutaneous MCTs?

A

typically solitary, small, slow growing, not ulcerated, and may be alopecic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
143
Q

What is the typical clinical appearance of poorly differentiated cutaneous MCTs?

A

usually rapidly growing, ulcerated, large, irritating, may cause inflammation or edema in surrounding tissues, and may cause small satellite nodules in surrounding tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
144
Q

What is the common history of cutaneous mast cell tumors?

A

waxing and waning size, which is associated with the intermittent release of mast cell granule contents which can cause edema and bleeding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
145
Q

What is the typical clinical appearance of subcutaneous mast cell tumors?

A

appear as quiet, subcutaneous swellings
- commonly mistaken for lipomas. (Personal tip: I have diagnosed several “lipomas” as MCTs or soft
tissue sarcomas. FNA any new mass, even if it looks lipomatous)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
146
Q

What are the paraneoplastic syndromes associated with mast cell tumors?

A

Darier’s sign
GI ulceration
- 35-83% on necropsy
Coagulation abnormalities
Delayed wound healing/dehiscence
Hypotension
Hypereosinophilia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
147
Q

What is Darier’s sign?

A

manipulation of the mast cell tumor during examination results in degranulation and subsequent wheal and flare in the surrounding tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
148
Q

How can mast cell tumors cause gastrointestinal ulceration?

A

histamine release from MCT granules acts on parietal cells via H2 receptors –> increased hydrochloric acid secretion and subsequent GI ulceration
- may also be an inhibition of normal gastrin feedback loops to
decrease gastric hydrochloric acid
histamine binding to H2 receptors also leads to increased gastrointestinal motility and capillary permeability, promoting intravascular thrombosis and mucosal ulceration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
149
Q

How can mast cell tumors cause coagulation abnormalities?

A

heparin release from MC granules can contribute to coagulation abnormalities
- may have normal normal presurgical coagulation parameters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
150
Q

How can mast cell tumors cause hypotension?

A

hypotension may result from vasodilation associated with the release of histamine, other vasoactive substances, and maybe prostaglandin D series

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
151
Q

How can mast cell tumors cause delayed wound healing/dehiscence?

A

release of vasoactive amines and proteolytic enzymes by MCs can lead to suppression of fibroblast growth factor, reducing fibroplasia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
152
Q

How can mast cell tumors cause hypereosinophilia?

A

associated with the release of eosinophil chemotactic factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
153
Q

What are the IHC stains for mast cell tumors?

A

vimentin (+)
tryptase (+)
KIT (CD117) (+)
chymase (+)
MCP-1(+)
IL-8 (+)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
154
Q

What is is the most consistent and reliable prognostic factor for cutaneous MCTs?

A

Histologic grade
- based on degree of MC differentiation
will not predict behavior of every tumor
*except subcutaneous mast cell tumors are not reliably graded by these systems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
155
Q

What is the Patnaik three-tiered grading system?

A

Grade I MCTs are low grade (well-differentiated)
- best type to have
- tend to not spread past skin
- surgery should be curative
- no chemotherapy is needed
- 80-90% do well after surgery
Grade II MCTs are intermediate grade
- somewhat unpredictable
- mitotic index may help
- < 5 had a MST of 70 months
- > 5 had a MST of 5 months
- 75% do well after surgery
Grade III MCTs are high grade (poorly differentiated)
- worst type to have
- behave invasively/aggressively
- to spleen/liver/bone marrow
- need more than surgery
- 55-96% are metastatic and die within in 1 year

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
156
Q

Where do cutaneous mast cell tumors tend to spread to?

A

Metastasis is usually to local lymph nodes first, then to spleen and liver and other organs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
157
Q

What is the Kiupel two-tiered grading system of mast cell tumors?

A

Divide them into high and low

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
158
Q

What factors have an influence on prognosis for mast cell tumors?

A

Histologic grade
Clinical stage
Location
Cell proliferation rate
Growth rate
Microvessel density
Recurrence
Systemic signs
Age
Breed
Sex
Tumor size
c-kit mutation
DNA copy number variation (CNV)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
159
Q

How can clinical stage be important for prognosis with cutaneous mast cell tumors?

A

Stages 0 and 1, confined to the skin without local lymph node or distant metastasis, have a better prognosis than higher stage disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
160
Q

How can histological grade be important for prognosis with cutaneous mast cell tumors?

A

Strongly predictive of outcome. Dogs with undifferentiated tumors typically die of their disease after local therapy alone, whereas those with well-differentiated tumors are usually cured with appropriate local therapy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
161
Q

How can location be important for prognosis with cutaneous mast cell tumors?

A

Subungual, oral, and other mucus membrane sites are associated with more high-grade tumors and worse prognosis.
Preputial and scrotal tumors are also associated with worse prognosis.
Subcutaneous tumors have better prognosis.
Visceral or bone marrow disease usually carries a grave prognosis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
162
Q

How can cell proliferation rate be important for prognosis with cutaneous mast cell tumors?

A

Mitotic index, relative frequency of AgNORs, and percent proliferating cell nuclear antigen, or Ki-67 immunopositivity are predictive of post-surgical outcome.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
163
Q

How can growth rate be important for prognosis with cutaneous mast cell tumors?

A

MCTs that remain localized and are present for prolonged periods of time (months or years) without significant change are usually benign.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
164
Q

How can microvessel density be important for prognosis with cutaneous mast cell tumors?

A

Increased microvessel density is associated with higher grade, a higher degree of invasiveness, and worse prognosis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
165
Q

How can recurrence be important for prognosis with cutaneous mast cell tumors?

A

Local recurrence after surgical excision may carry a more guarded prognosis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
166
Q

How can systemic signs be important for prognosis with cutaneous mast cell tumors?

A

The presence of systemic illness (hyporexia, vomiting, melena, GI ulceration) may be associated with a higher stage of disease.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
167
Q

How can age be important for prognosis with cutaneous mast cell tumors?

A

Older dogs may have shorter median disease-free intervals when treated with radiation therapy than younger dogs.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
168
Q

How can breed be important for prognosis with cutaneous mast cell tumors?

A

MCTs in boxers and other brachycephalic breeds tend to be of low or intermediate grade and a better prognosis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
169
Q

How can sex be important for prognosis with cutaneous mast cell tumors?

A

Males have a shorter survival time than female dogs when treated with chemotherapy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
170
Q

How can tumor size be important for prognosis with cutaneous mast cell tumors?

A

Large tumors may be associated with worse prognosis after surgical removal and/or radiation
therapy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
171
Q

How can c-kit be important for prognosis with cutaneous mast cell tumors?

A

Activating mutations in c-kit are associated with a worse prognosis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
172
Q

How can DNA copy number variation (CNV) be important for prognosis with cutaneous mast cell tumors?

A

Higher CNVs are associated with higher grade tumors and worse prognosis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
173
Q

What are associated with prognosis in subcutaneous mast cell tumors?

A

Mitotic index, multinucleation, and degree of tissue infiltration

174
Q

What is the recommended treatment of low to intermediate grade mast cell tumors localized to the skin?

A

wide surgical excision is treatment of choice
Marginal excision (no gross residual disease) may be acceptable
Not all tumors with incomplete excisions will recur

175
Q

What is the recommended treatment of high grade MCTs, intermediate grade MCTs with regional or distant metastases, or mucocutaneous / mucus membrane junction MCT?

A

chemotherapy and/or RT +/- surgery

176
Q

How can prednisone help with mast cell tumors?

A

inhibits MC proliferation, induces tumor cell apoptosis in vitro, and decreases peritumoral edema and inflammation

177
Q

What are the tyrosine kinase inhibitors used to treat mast cell tumors?

A

toceranib (Palladia)
masitinib (Masivet)
imatinib (Gleevec)

178
Q

How does stelfonta (tigilanol tiglate) work?

A

newer treatment that involves intratumoral injection of a potent cellular signaling molecule which results in rapid destruction of the treated tumor by hemorrhagic necrosis and tumor sloughing

179
Q

Which form of mast cell tumor is most amenable to cure with surgery?

A

Subcutaneous MCTs

180
Q

What are some ancillary therapies for mast cell tumors?

A

important when systemic signs are present
- Antihistamines
- Antacids
- GI protectants

181
Q

What are the three syndromes of mast cell tumors in cats?

A

cutaneous
- histiocytic and mastocytic
splenic/visceral
intestinal

182
Q

What is the typical signalment of cats with mast cell tumors?

A

Mean age is 8-9 years
No sex predilection
Histiocytic type appears younger
- mean 2.4 years old
Siamese cats may be predisposed

183
Q

What are histiocytic MCTs in cats?

A

predominantly found in young cats
Siamese cats predisposed
less common than the mastocytic subtype
presents as multiple, non-pruritic, firm, hairless, pink, and sometimes ulcerated SQ nodules

184
Q

What are mastocytic MCTs in cats?

A

more common type
most commonly a solitary, raised, firm, well-circumscribed, hairless, white to pink/erythematous, dermal nodule up to 3cm diameter, with variable ulceration
- 20% may have multiple
some cats may present with what looks like discrete subcutaneous nodules (suggestive of panniculitis) or eosinophilic plaques
Pruritus is variable
typically on the head and neck
- base of the pinna
Oral cavity may be affected
Darier’s sign may be present

185
Q

Which form of MCT in cats may be difficult to diagnose on cytology?

A

histiocytic form
MCs may comprise only 20% of the cells (the majority are histiocytes, followed by eosinophils and lymphocytes, potentially looking a lot like inflammation or granulomatous nodular panniculitis / dermatitis)

186
Q

Where, internally, are mast cell tumors frequently found in cats?

A

spleen

187
Q

What is the typical behavior of feline mast cell tumors?

A

in general, feline cutaneous MCTs behave in a more benign way than canine MCTs

188
Q

How are feline mast cell tumors graded on histopathology?

A

histopathologic grading systems used in dogs are not reliable predictors in cats
Mitotic index in cats is often associated with higher risk
- but some may still be benign
mastocytic type of feline MCTs may be histopathologically categorized as compact (50-90% of cases) or diffuse (anaplastic)
- anaplastic may be more malignant

189
Q

How is number of mast cell tumors important for cats?

A

Cats with one cutaneous MCT have a better prognosis for survival than those with 5 or more
cutaneous MCTs.

190
Q

How is the histiocytic form of mast cell tumor treated in cats?

A

may spontaneously regress over 4-24 months
Conservative surgical resection or active surveillance (monitoring) can be pursued

191
Q

How is the mastocytic form of mast cell tumor treated in cats?

A

If well-differentiated with low mitotic figures
- surgical excision
- Local recurrence is uncommon but possible.
Poorly differentiated / high mitotic figure MCTs
- treated like aggressive canine
mast cell tumors, with a combination of chemotherapy +/- RT +/- surgery
- Gleevec and lomustine have been used

192
Q

What is the typical signalment of urticaria pigmentosa in dogs?

A

Only a small number of dogs overall
usually < 1 yr
a middle-aged dog was reported

193
Q

What is the typical clinical appearance of urticaria pigmentosa in dogs?

A

non-pigmented
head, neck, trunk, perineum, and legs
May be up to 5cm
- single, multiple, or numerous
+/- Darier’s sign and pruritus
Other signs of MC degranulation

194
Q

What is the typical histopathologic appearance of urticaria pigmentosa in dogs?

A

moderate to severe perivascular to diffuse, nonencapsulated and poorly demarcated infiltration of well-differentiated MCs in the dermis

195
Q

What is the treatment of urticaria pigmentosa in dogs?

A

May spontaneously regress or progress to systemic signs
Excellent response has been noted with oral glucocorticoids, H1 blockers, and H2
blockers

196
Q

What is the typical signalment of urticaria pigmentosa in cats?

A

Average age is <1 year
Devon Rex and Sphynx are predisposed

197
Q

What are the 3 clinical presentations of urticaria pigmentosa?

A

(1) non-pigmented papules and wheals on the head, shoulders, ventral neck, and axillae, with pruritus
(2) non-pigmented maculopapular erythematous dermatitis with crusts and pruritus
(3) highly pruritic chronic dermatitis with bilaterally symmetrical linearly distributed, pigmented lesions on the flanks
(Darier’s sign is typically negative in all)

198
Q

What is the typical histopathologic appearance of urticaria pigmentosa in cats?

A

moderate to severe perivascular to diffuse, nonencapsulated and poorly demarcated infiltration of well-differentiated MCs in the dermis, with numerous eosinophils

199
Q

What has been found about c-kit mutations in dogs with urticaria pigmentosa?

A

No dogs had mutations in c-KIT exons 8 and 11

200
Q

What is the primary differentials for urticaria pigmentosa in cats?

A

Dermatophytosis: has been reported in three cases that clinically mimicked MPCM but were diagnosed with histopathology
MC tumor: may initially present as papules but is typically not pruritic and found in older cats

201
Q

What IHCs can be used for urticaria pigmentosa in cats?

A

Tryptase
KIT

202
Q

What is the treatment for feline urticaria pigmentosa?

A

Prognosis is variable
May have spontaneous regression
- more likely with non-pigmented papules/wheals
May be progressive and aggressive
Systemic glucocorticoids, antibiotics (amoxicillin/clavulanic acid or doxycycline) and/or blackcurrant seed oil, and also antihistamines (hydroxyzine/cetirizine) in addition to shampoo or cyclosporine

203
Q

What is disseminated / diffuse cutaneous mastocytosis?

A

Rare condition in dogs and cats
May involve c-kit mutation for dogs
Typically progresses to systemic
Poor response to treatment
- may lead to euthanasia

204
Q

What is systemic mastocytosis with disseminated cutaneous mastocytosis?

A

Very rare condition in dogs and cats
Visceral form (splenic or intestinal) of feline MCTs has also been referred to as systemic
mastocytosis but this doesn’t met to skin

205
Q

What are the cutaneous lymphoproliferative disorders in dogs and cats?

A

(1) Cutaneous lymphoma
(2) Cutaneous lymphocytosis
(3) Lymphomatoid granulomatosis
(4) Extranodal lymphoma with cutaneous involvement
(5) Reactive lymphoid hyperplasia

206
Q

Where are neoplastic lymphocytes found in epitheliotropic lymphoma?

A

epithelial tissues of epidermis/hair
due to expression of specific integrins

207
Q

Where are neoplastic lymphocytes found in non-epitheliotropic lymphoma?

A

neoplastic lymphocytes are found in the dermis and subcutis

208
Q

What type of lymphocytes are found in epitheliotropic lymphoma?

A

most commonly have a T-cell origin, and B-cell tumors are rare
- dogs are usually CD3/CD8+ and γδ
- may have increased CD25+ T-cells
- humans are usually CD3/CD4+

209
Q

What is thought to be a risk factor for epitheliotropic lymphoma?

A

chronic inflammation
FeLV may play a role in cats

210
Q

How is COX-2 thought to play a role in cutaneous neoplasms?

A

increasing angiogenesis, invasiveness, and metastasis; inducing resistance to apoptosis; and suppressing immune responses

211
Q

How are COX-2 inhibitors thought to have anti-neoplastic activity?

A

inhibition of PGE2 synthesis

212
Q

What are Pautrier’s microabscesses?

A

discrete collections of neoplastic lymphocytes in the upper layers of the epidermis

213
Q

Which anatomical location in cats has an especially poor prognosis for epitheliotropic lymphoma?

A

tarsus
MST of 190 days

214
Q

What is associated with a poorer prognosis to cutaneous lymphoma?

A

f neoplastic lymphocytes in peripheral blood, thrombocytopenia, and poor initial chemotherapeutic response

215
Q

The increased transcription of which cytokines is associated with epitheliotropic lymphoma in dogs?

A

Th-1 type cytokines IL-12 and IFN-gamma

216
Q

Increased levels of which T-cell markers are associated with epitheliotropic lymphoma in dogs?

A

perforin and granzyme B
normally associated with CD8+ T-cells

217
Q

What breeds of dogs are likely to be predisposed to epitheliotropic lymphoma in dogs?

A

English cocker spaniels, boxers, and golden retrievers

218
Q

What are the 3 clinical forms of epitheliotropic lymphoma in dogs?

A

(1) mycosis fungoides
(2) pagetoid reticulosis
(3) Sezary syndrome

219
Q

What is mycosis fungoides?

A

a form of epitheliotropic lymphoma in dogs
exfoliative erythroderma
depigmented mucocutaneous lesions
erosions or ulcers
solitary/multiple nodules or plaques
infiltrative oral mucosal disease
rare vesiculobullous variant
will have neoplastic lymphocytes in the dermis

220
Q

What is Sezary syndrome?

A

progressive form of mycosis fungoides
skin lesions
develop leukemia
- Sezary cells

221
Q

What is pagetoid reticulosis?

A

dogs have similar signs to mycosis fungoides
distinction is made histopathologically
neoplastic infiltrate is solely in the epidermis and adnexal structures

222
Q

What is the prognosis of cutaneous lymphoma in dogs?

A

poor, ranging from a few months to 2 years (median survival time 6 months)

223
Q

Is mucosal involvement of cutaneous lymphoma in dogs associated with a worse prognosis?

A

No
Mucosal lesions: MST 491 days
Skin lesions: MST 130 days

224
Q

Where are lesions due to epitheliotropic lymphoma typically found in cats?

A

face, eyelids, mucocutaneous junctions, elbows, and trunk

225
Q

Is epitheliotropic lymphoma or cutaneous non-epitheliotropic lymphoma more commonly associated with skin lesions?

A

epitheliotropic is more common in dogs
non-epitheliotropic is more common in cats

226
Q

What type of lymphocyte is typically associated with cutaneous non-epitheliotropic lymphoma?

A

T-cell infiltrates are more common than B-cell
most are CD8+ or CD4-/CD8-

227
Q

What is the typical histopathologic findings of cutaneous non-epitheliotropic lymphoma?

A

predominantly deep dermal and subcutaneous nonencapsulated masses
composed of sheets, clusters or nodular
- a bottom-heavy or base-wide
perivascular aggregates of relatively monomorphic cells
Grenz zone in superficial dermis
adnexal structures are typically not invaded

228
Q

What are the typical clinical lesions of cutaneous non-epitheliotropic lymphoma?

A

single to multiple to diffuse dermal or subcutaneous nodules
can mimic panniculitis
typically rapidly progressive
- metastasis to draining lymph nodes
paraneoplastic hypercalcemia is possible

229
Q

What is the relative prognoses of different types of lymphoma in the skin?

A

B-cell is best for dogs, worse for cats
cutaneous non-epitheliotropic lymphoma is better than epitheliotropic lymphoma
panniculitis-type T-cell non-epitheliotropic lymphomas in dogs is particularly aggressive

230
Q

What is cutaneous lymphocytosis?

A

more common in cats than dogs
may be a more indolent, slowly progressive form of cutaneous lymphoma
- monoclonal lymphoid populations
stable or very slowly progressive disease
- might become malignant/systemic
- unknown if just initial misdiagnosis

231
Q

What is the pathogenesis of cutaneous lymphocytosis in dogs?

A

Most lymphocytes are a/b T-cells
About half co-express CD8+ or are CD4-/CD8-There may be small aggregates of B-cells in the infiltrate

232
Q

What is the typical clinical appearance of cutaneous lymphocytosis in dogs?

A

Dogs often present with multifocal erythema, alopecia, scale, and plaques
Nodules and papules have not been reported in dogs (unlike cats)
pruritus is rarely a feature

233
Q

What is the most common treatment of cutaneous lymphocytosis in dogs?

A

Glucocorticoids

234
Q

What is the pathogenesis of cutaneous lymphocytosis in cats?

A

Most infiltrating lymphocytes are CD18+, CD3+, and CD5+ T-cells
May be small aggregates of B-cells in the infiltrate

235
Q

What is the typical clinical appearance of cutaneous lymphocytosis in cats?

A

single lesion of erythema, scale, and alopecia +/- crusting
Erythematous plaques, nodules, or papules may be seen
Pruritus is common
Lesions are most common over the thorax but can be seen anywhere, including the legs, pinnae, flank, and neck

236
Q

What is the pathogenesis of cutaneous lymphocytosis in cats?

A

systemic or topical glucocorticoids
or chlorambucil or lomustine

237
Q

What is lymphomatoid granulomatosis (angioinvasive lymphoma)?

A

rare lymphohistioticytic proliferative disorder
angio-invasive and angio-destructive, proliferation of large atypical lymphohistiocytic cells
- small lymphocytes, plasma cells, and histiocytes
may represent a form of atypical non-epitheliotropic T-cell lymphoma
systemic involvement is a consistent finding, primarily in the lung
- cats can have lungs, liver, spleen, eye, skin, and subcutis
combinations of CD3, CD20, and CD79 positivity in dogs
- mixed B and T cells in cats
poor prognosis - MST ~2 months

238
Q

What is extranodal lymphoma with cutaneous manifestations?

A

can be a cause of otitis media/interna in cats
most are T-cell origin; 1 case was a non-B, non-T-cell lymphoma
Prognosis was poor for survival

239
Q

What is lymphoid hyperplasia?

A

reported in one cat presenting with a unilateral erythematous, scaly, alopecic, swelling on the muzzle
was not neoplastic

240
Q

What is hepatocutaneous syndrome?

A

complex disorder involving SND lesions, a distinct hepatopathy (hepatocutaneous‐associated hepatopathy, HCH), hypoaminoacidemia, and aminoaciduria

241
Q

What is the treatment for hepatocutaneous syndrome?

A

IV‐AA infusions, high protein diets, traditionally commercial diets supplemented with whey protein +/- zinc supplementation
Somatostatin analogues (octreotidum) is used in people

242
Q

What is the typical signalment of dogs with hepatocutaneous syndrome?

A

more commonly reported in small breed geriatric dogs and had a male predisposition
Cocker spaniel, Shetland sheepdog, Shih Tzu, and West Highland White terrier are predisposed

243
Q

What is necrolytic migratory erythema typically associated with in humans?

A

pancreatic tumor that secretes glucagon (glucagonoma)
- not typical for dogs

244
Q

Why is hypoacidemia thought to occur with hepatocutaneous syndrome?

A

elevated gluconeogenesis due to hyperglucagonemia (associated with pancreatic tumors) or heightened hepatic breakdown of amino acids (in cases of chronic liver disease) leads to decreased plasma amino acid levels and depletion of epidermal proteins

245
Q

What are some clinical findings associate with hepatocutaneous syndrome?

A

anemia, microcytosis, elevated alkaline phosphatase activity, and hypoalbuminemia

246
Q

What causes the Swiss cheese-like appearance of the liver on ultrasound with hepatocutaneous syndrome?

A

Vacuolar hepatopathy
- Glycogen-vacuolated hepatocytes
collapse of the areas of parenchyma surrounding the nodules rather than to the cirrhosis and/or nodular hyperplasia reported previously

247
Q

What is the typical cutaneous lesions associated with hepatocutaneous syndrome?

A

Erosions, ulcers, crusts
Pawpads, MC junctions, oral cavity, pinna, pressure points
Horses hoof wall sloughing
Secondary infections are common
Pruritus may be minimal to intense
Often painful

248
Q

What is the typical histopathologic appearance of hepatocutaneous syndrome?

A

diffuse parakeratotic hyperkeratosis, intracellular edema of the granular epithelial cells and basal cell hyperplasia
“red, white, and blue”

249
Q

What are the reported causes of hepatocutaneous syndrome in dogs?

A
  1. Hepatic disease (>90%)
    • vacuolar idiopathic, toxic, or metabolic
  2. Hypoaminoacidemia
  3. Glucagon producing tumors (pancreas)
250
Q

What is feminization syndrome?

A

24-57% of dogs with a Sertoli cell tumor
shift of balance btw estradiol and testosterone
linear preputial dermatitis
signs of hyperestrogenism

251
Q

What is the histopathological findings of paraneoplastic (thymoma)-associated exfoliative dermatitis?

A

cell-poor or rich interface dermatitis affecting the epidermis and the hair follicle with apoptosis of keratinocytes, satellitosis and a lymphocytic dermal infiltrate as well as reduced or absent sebaceous glands
- EM meets sebaceous adenitis

252
Q

What is the pathogenesis of paraneoplastic (thymoma)-associated exfoliative dermatitis?

A

not fully understood, but aberrant auto-antigen-responsive T-cells are implicated

253
Q

What are the clinical signs of paraneoplastic (thymoma)-associated exfoliative dermatitis?

A

Cutaneous lesions: severe exfoliation or scaling, hypotrichosis and erythema without pruritus
lesions usually start on the head and pinna, becoming generalized
Tend to precede the systemic signs
Anorexia, lethargy, cough, hypercalcemia, myasthenia gravis, keratoconjunctivitis sicca, polymyositis, thrombocytopenia, anemia, granulocytopenia

254
Q

What is the treatment for paraneoplastic (thymoma)-associated exfoliative dermatitis?

A

Surgical resection is the treatment of choice if the thymoma is excisable
If able to be removed, prognosis is good and skin lesions improve within a few months

255
Q

What species has paraneoplastic (thymoma)-associated exfoliative dermatitis been reported in?

A

Cats (classic), rabbits, goats

256
Q

What has been reported as a cause of paraneoplastic alopecia in cats?

A

pancreatic carcinoma > biliary carcinoma, hepatic carcinoma or plasma cell tumor, or metastasizing intestinal carcinoma

257
Q

What are the clinical signs of feline paraneoplastic alopecia?

A

acute, progressive symmetrical alopecia, easily epilated hairs and an underlying shiny and thin skin
Some cats groom excessively
leads to the postulation that thereby the stratum corneum is exfoliated leading to the shiny skin
Lesions affect mainly the limbs, flanks and the face but eventually become generalized
Foot pads are also affected and are either dry, crusted and fissured, or erythematous and moist
Secondary Malassezia-dermatitis is possible

258
Q

What are the histopathologic findings associated with feline paraneoplastic alopecia?

A

absence of the stratum corneum, marked follicular telogenisation, miniaturization and atrophy

259
Q

What is the prognosis of feline paraneoplastic alopecia?

A

In the vast majority of cases, the neoplasia has already metastasized so the prognosis is grave

260
Q

Other than thymoma-associated exfoliative dermatitis, which immune-mediated diseases have been associated with neoplasia?

A

Paraneoplastic pemphigus (similar to PV)
Erythema multiforme/SJS
Sterile nodular panniculitis

261
Q

What is an isthmic and inferior stem cell marker panel?

A

CK8, CK15, CK19, and CD34

262
Q

What is survivin?

A

inhibits apoptosis and maintains stem cells
partial co-localization with CK15 in trichoepitheliomas and trichoblastomas

263
Q

Which hair follicle tumors are derived from the inferior or lower isthmic segment?

A

Inferior tricholemmoma
Malignant trichoepithelioma
Trichoepithelioma
Pilomatricoma

264
Q

Which hair follicle tumors are derived from the middle isthmic segment?

A

IKA
isthmic tricholemmoma

265
Q

Which hair follicle tumor does not have keratinization?

A

Trichoblastoma
ribbons, medusoid, or trabeculae
*granular form has abrupt

266
Q

Which hair follicle tumors come from hair germ origin?

A

Trichoblastoma

267
Q

Which hair follicle tumor has all gradual (lamellar) keratinization?

A

Infundibular keratinizing acanthoma
- lamellar keratin
- trichohyalin granules
- +/- central pore (based on cut)
- mucin, cartilage/mineralization

268
Q

Which hair follicle tumor has all abrupt keratinization?

A

Pilomatricomas
- ghost cells
- matrical cells (basaloid)
- +/- trichohyalin granules
- mineral, bone, melanin
- +/- amyloid

269
Q

Which hair follicle tumor has mixed abrupt and gradual keratinization?

A

Trichoepitheliomas
- lamellae and ghost cells
- kerato- and trichohyalin granules

270
Q

Which breed is predisposed to infundibular keratinizing acanthomas?

A

Norwegian Elkhounds overall
Young, male Norwegian Elkhounds and Keeshonds are predisposed to having numerous nodules (up to 40–50 nodules)

271
Q

What is the histological appearance of infundibular keratinizing acanthomas?

A

Well-demarcated, dermal, cup-shaped lesions, consisting of a cyst that is filled with lamellar, concentric keratin, and has a central pore opening to the epidermal surface

272
Q

What is the treatment for infundibular keratinizing acanthomas?

A

surgical excision +/- oral retinoids if many

273
Q
A

infundibular keratinizing acanthoma

274
Q

Which breed is predisposed to tricholemmomas?

A

Afghan Hounds may be predisposed

275
Q

What are the histopathologic findings of tricholemmomas?

A

well demarcated, non-encapsulated tumors with a low mitotic rate
2 types - the isthmic and the inferior/bulb
- neither has granules
- isthmic have trichilemmal keratinization
- inferior has lobular groupings with small cells arranged in islands/nests/trabeculae

276
Q

Which hair follicle tumors have no keratohyalin or trichohyalin granules?

A

tricholemmomas

277
Q

Which breed is predisposed to pilomatricomas?

A

Most common in breeds with a continuously growing hair coat and anagen predominance
Esp Kerry Blue Terriers

278
Q

Where do pilomatricomas arise from?

A

hair matrix of the hair bulb

279
Q

What is the typical histopathologic findings of pilomatricomas?

A

well-circumscribed dermal/SC tumor
multiple cystic structures of variable size
- lined by small, basaloid (matrical) cells
- trichohyalin granules usually present
- frequently exhibit high mitotic activity

280
Q

What are matrical carcinomas?

A

Pilomatricas that show invasive tendencies on histopathology
- may have distant metastasis

281
Q
A

Canine inferior tricholemmoma.
A. Well-demarcated tumor in the deep dermis and subcutis with islands and trabeculae of neoplastic cells. H&E. 4×. B. Nests of neoplastic cells with vacuolated, peripherally palisading cells in the outer layer and multifocally more eosinophilic cytoplasm in the center (asterisk). Note that a distinct basement membrane surrounds each tumor cell aggregate (arrow). H&E. 40×

282
Q
A

Canine pilomatricoma
A–C. Benign pilomatricoma. A. Multilocular, cystic structures of variable size lined by basaloid matrical cells. H&E. 2×. B. Small, basaloid matrical cells line the cyst and have abrupt keratinization. Ghost cells (arrow) are within the lumen. Note red trichohyalin granules (inset). H&E. 60×. C. Example of rupture of the tumor resulting in pyogranulomatous inflammation surrounding a large number of ghost cells. H&E. 20×. D–F. Malignant pilomatricoma. D. Unencapsulated, infiltrative, poorly circumscribed tumor. Note contiguity with epidermis, which is ulcerated. H&E. 2×. E. Infiltrative basaloid cell population. Note desmoplasia surrounding neoplastic cells. H&E. 20×. F. Neoplastic basaloid cells with numerous atypical mitotic figures (black arrows). Note single cell necrosis (white arrow). H&E. 40×.

283
Q

Where do trichoblastomas arise from?

A

the primitive hair germ of embryonal follicular development

284
Q

What is the breed and age predilection for trichoblastomas in dogs?

A

Poodles, Cocker Spaniels, and mixed-breed
→ long anagen?
4–10 y old
Male dogs appear predisposed

285
Q

What is the typical age of onset for most hair follicle tumors in dogs?

A

Middle aged (not very geriatric)

286
Q

Where are trichoblastomas typically found?

A

most common on the head and neck, especially at the base of ears
In cats this predisposition extends to the cranial half of the trunk

287
Q

What are the 5 subtypes of trichoblastomas?

A

Ribbon or medusoid
Granular cell
Trabecular
Spindle
with ORS differentiation

288
Q

What is the most common subtype of trichoblastomas in dogs?

A

Ribbon or medusoid

289
Q

What is the most common subtype of trichoblastomas in cats?

A

Trabecular

290
Q

What is the typical appearance of spindle trichoblastomas?

A

lima bean–like silhouette with a central indentation, a broad epidermal connection, and ulceration consists of basaloid epithelial cells arranged in islands, nests, and short trabeculae

291
Q

What is the typical appearance of trichoblastomas with ORS differentiation?

A

composed of multiple lobules, trabeculae and areas of cystic degeneration as a result of acantholysis and drop-out of keratinocytes
Small keratinocytes form anastomosing cords which merge into small islands of cells or into trabeculae

292
Q
A

Trichoblastoma
A, B. Canine ribbon trichoblastoma. Note ribbon-like columns radiating from central epithelial nests in B. H&E. 2× and 20×, respectively. C, D. Canine trabecular trichoblastoma. Note peripheral palisading of cells in D. H&E. 2× and 20×, respectively. E, F. Feline spindle trichoblastoma. Note spindle-shaped cells arranged in fascicles in F. H&E. 2× and 20×, respectively. G–I. Canine trichoblastoma with outer root sheath differentiation. Note cystic center (G) lined by glycogenated cells (H) and multifocal heavy melanization (I). H&E. 2× (G) and 20× (H, I), respectively.

293
Q

What breed of dog is predisposed to trichoepitheliomas?

A

Bassett hounds
- Spayed female dogs may be
Persian cats

294
Q

What is the histopathologic appearance of trichoepitheliomas?

A

well-circumscribed, usually non-infiltrative, unencapsulated tumors consisting of epithelial islands and cystic structures of variable size that show differentiation toward all 3 of the follicular segments
Have both keratohyalin and trichohyalin granules
Dystrophic mineralization may occur, but mineralization and osseous metaplasia are not prominent features

295
Q

What are malignant epitheliomas?

A

Spayed females and the Basset Hound and Airedale Terrier breeds may be predisposed
Older dogs 8–12 y
Appears similar to the benign version but is more invasive and sketchy looking

296
Q

What is the typical treatment of hair follicle tumors?

A

surgical excision

297
Q
A

Canine trichoepithelioma
A–D. Benign trichoepithelioma. A. Well-circumscribed tumor consisting of cystic structures. Note area of inflammation as a result of rupture of the tumor (asterisk). H&E. 2×. B. Cysts are lined by squamous epithelium. H&E. 20×. C. Cysts are lined by both squamous epithelium and matrical cells. Note both blue keratohyalin and red trichohyalin granules (insets). H&E. 40×. D. Cysts lined by matrical cells have abrupt keratinization without a granular layer. Note ghost cells within the cyst (arrow). H&E. 60×. E, F. Malignant trichoepithelioma. E. Unencapsulated, infiltrative, poorly circumscribed tumor. Note contiguity with epidermis. H&E. 20×. F. Infiltrative basaloid cell population lining cyst-like structure filled with keratin and ghost cells. Note severe desmoplasia surrounding epithelial cells. H&E. 20×.

298
Q

What is a trichofolliculoma?

A

More likely nonneoplastic, hamartoma-like lesions rather than true neoplasms
uncommon in dogs and rare in cats, also occurs in guinea pigs
usually appears as a well-circumscribed, unencapsulated dermal nodule composed of one or several, large, dilated primary HFs filled with keratin and hair shafts

299
Q
A

Trichofolliculoma in a guinea pig
A. Well-demarcated, unencapsulated mass consisting of a few dilated, central primary hair follicles, surrounded by many secondary hair follicles. H&E. 2×. B. Secondary hair follicles radiate from the primary hair follicle in an arborizing pattern. H&E. 10×. C, D. Note various stages of maturation ranging from primitive hair germ (C) to fully developed hair follicles with a well-developed hair bulb and red trichohyalin granules (arrow). D. Note well-differentiated sebaceous glands in C and D (asterisks). H&E. 40× (C) and 20× (D).

300
Q

What are dermoid cysts?

A

Focal reduplications of the skin resulting from incomplete separation of the cutaneous ectoderm and neuroectoderm during embryogenesis, and they include epidermis, dermis, and adnexal structures

301
Q

Which breeds are predisposed to dermoid cysts?

A

Rhodesian Ridgebacks and Boxers are predisposed and often have multiple cysts on the dorsal midline

302
Q

What age group is typically diagnosed with dermoid cysts?

A

Since they are developmental anomalies, young animals (<2 y old) are affected primarily

303
Q

Where are dermoid cysts found?

A

dorsal midline and occasionally may extend to the spinal canal and attach to the dura mater
can also be found on the lateral neck or shoulder, particularly in cats

304
Q

What are the histopathologic findings associated with dermoid cysts?

A

Can be either dermal or subcutaneous
are lined by squamous epithelium with prominent keratohyalin granules
contain lamellar keratin, hair fragments, and sometimes sebaceous secretions
Hair shafts are frequently present

305
Q

What are the 5 types of follicular cysts?

A

Infundibular follicular cysts
Isthmus cysts
Matrical cysts
Hybrid cysts
Panfollicular cysts

306
Q

What are infundibular follicular cysts?

A

Common in dogs and cats
lined by squamous epithelium with keratohyalin granules, and are filled by lamellar, often concentric keratin occasionally with a few sebaceous glands are attached
In Merino sheep, these cysts are often multiple and may progress to squamous cell carcinomas

307
Q

What are isthmus follicular cysts?

A

In dogs and (rarely) in cats
The pattern closely resembles the isthmus ORS, with granules absent and the cyst is filled with amorphous, trichilemmal keratin
Siberian Huskies have a type that is flame follicle–like

308
Q

What are matrical follicular cysts?

A

Mostly occur in dogs and cats
wall resembles the epithelium of the hair bulb, may have trichohyalin granules, and have abrupt keratinization

309
Q

What are hybrid and panfollicular cysts?

A

Hybrid cysts are derived from 2 HF segments
Panfollicular cysts have differentiation to all 3 parts of the HF

310
Q

What are keratomas?

A

cystic lesions in the hoof wall of the toe or, less frequently, the quarter or heel in simple or cloven-hoofed animals
often develop secondary to a traumatic injury
induce lameness and deformity of the hoof wall or sole and may be associated with distal phalangeal lysis

311
Q

What are dilated pores of Winer?

A

rare, hair-follicle neoplasms recognized only in senior cats, primarily males and on the head
also found in a horse

312
Q
A

Infundibular cyst

313
Q
A

Isthmus cyst

314
Q
A

Matrical cyst

315
Q
A

Hybrid cyst

316
Q

What is is overexpressed in equine squamous cell carcinomas to an extent compatible with gene mutation?

A

p53 gene

317
Q

What inflammatory response is associated with squamous cell carcinomas in horses?

A

numerous CD3+ T-lymphocytes, CD79+ B-lymphocytes, immunoglobulin G+ plasma cells, and macrophages

318
Q

What are basal cell tumors in horses?

A

a large group of neoplasms
numerous histopathologic “subclassifications”
most are benign
generally show differentiation toward follicular structures
- reclassified in dogs and cats

319
Q

What are cystic apocrine gland dilations?

A

Best characterized as hamartomas
Two forms exist:
- cystic form in upper/mid dermis with poor association with hair follicles
- more diffuse form with cystically dilated apocrine glands associated with multiple hair follicles
middle-age or older dogs
less commonly, cats
Head and neck are the most common sites where these lesions develop
Appear as fluctuant dermal cysts or as translucent bullae
Complete excision is curative

320
Q

What are apocrine gland adenomas?

A

dogs, cats, and rarely horses
form benign cysts
Two types:
- secretory (more common)
- ductular (less cystic)
Complete surgical excision is curative

321
Q

What breeds are most at risk for apocrine gland adenocarcinomas?

A

For dogs: Treeing Walker Coonhounds, Norwegian Elkhounds, German Shepherd Dogs, and mixed-breed dogs are most at risk
For cats: Siamese may be predisposed

322
Q

Where do apocrine gland adenocarcinomas tend to arise?

A

axillary and inguinal regions

323
Q

How do apocrine gland adenocarcinomas tend to behave?

A

locally invasive and frequently metastasize to draining lymph nodes
Less commonly, skin and lung metastasis may occur

324
Q

What dogs are most at risk for apocrine gland anal sac adenocarcinomas?

A

Older English Cocker Spaniels, Springer Spaniels, Dachshunds, Alaskan Malamutes, German Shepherd Dogs, and mixed-breed dogs are most at risk

325
Q

What can apocrine gland anal sac adenocarcinomas be associated with?

A

humoral hypercalcemia of malignancy
causes anorexia, weight loss, polyuria and polydipsia, and mineralization of renal tissue with increased BUN and creatinine concentrations

326
Q

How do apocrine gland anal sac adenocarcinomas tend to behave?

A

highly infiltrative into the pelvic canal
commonly (90%) metastasize to the sublumbar lymph nodes or to distant internal organs (40%)

327
Q

What is the typical treament for apocrine gland anal sac adenocarcinomas?

A

Wide surgical excision, including involved lymph nodes, is the treatment of choice
Intracavitary chemotherapy with 5-fluorouracil mixed with the animal’s serum may help local control
Follow-up radiation therapy, intralesional chemotherapy, tyrosine kinase inhibitor, or systemic chemotherapy may increase the tumor-free interval
Few dogs are reported to live >1 year after the tumor has been recognized

328
Q

What are eccrine gland tumors in dogs?

A

Extremely rare
Have only been identified in footpads of dogs and cats
Most are malignant and invasive with metastasis to draining lymph nodes

329
Q

What are sebaceous gland hamartomas?

A

benign tumors
solitary lesions reported only in dogs
linear or circumscribed and several centimeters in length or diameter
usually identified shortly after birth.

330
Q

What are sebaceous gland hyperplasias (senile sebaceous hyperplasias)?

A

benign tumors
represent a senile change in dogs and cats
In dogs: Manchester Terriers, Wheaten Terriers, and Welsh Terriers are at greatest risk
In cats: there is no breed predilection, but females develop these lesions more frequently than males
Location: skin of the head and abdomen are affected most commonly

331
Q

What are sebaceous gland adenomas?

A

benign tumors
Seen in all domestic animals
Very common in older dogs and cats
For dogs: Coonhounds, English Cocker Spaniels, Cocker Spaniels, Huskies, Samoyeds, and Alaskan Malamutes are most likely breeds
frequently are clinically indistinguishable from sebaceous hyperplasias, but they tend to be larger (typically >1 cm)
For cats: Persians

332
Q

What are sebaceous gland epitheliomas?

A

benign tumors
variant of sebaceous adenoma distinguished by lobules composed primarily of basal progenitor cells rather than mature sebocytes
occasionally be confused with sebaceous carcinomas
found in older dogs and rarely in cats.
Clinical appearance: ulcerated nodules that may be several centimeters in diameter
A papillated epidermal surface and pigmentation are variable findings

333
Q

What are sebaceous gland adenocarcinomas?

A

recognized almost exclusively in dogs and cats
generally in middle-aged or older animals
For dogs: Cavalier King Charles Spaniels; Cocker Spaniels; and Scottish Terriers, Cairn Terriers, and West Highland White Terriers are most at risk
Sex: Male dogs/female cats may be predisposed
locally infiltrative and may metastasize

334
Q

What are hepatoid gland tumors?

A

Arise from modified sebaceous glands around the anus (also present on the ventral midline, tail, and lumbar/sacral regions)
Intact male dogs are 3x more likely to develop them than female due to influence of androgen
adenomas versus adenocarcinomas

335
Q

What are hepatoid gland adenomas?

A

Most common in senior dogs esp Siberian Huskies, Samoyeds, Pekingese, and Cocker Spaniels
90% are found in the perianal region
<95% of male dogs respond completely to castration
Excision or laser ablation surgery may be used, recurrence is common especially in females
Radiation therapy is also an option and has a 2-year cure rate of 69% for benign tumors
Cryosurgery or electroporation are additional therapeutic alternatives
- may cause fecal incontinence

336
Q

What are hepatoid gland adenocarcinomas?

A

uncommon canine neoplasms
generally appear as nodular lesions affecting the perianal region
found in male dogs 10 times more commonly than in females
Siberian Huskies, Alaskan Malamutes, and Bulldogs are most likely to develop this tumor
have metastatic potential and often spread to regional lymph nodes
Treatment consists of wide surgical excision including involved lymph nodes and, possibly, subsequent radiation
- masitinib, toceranib, and other tyrosine kinase inhibitors may overcome chemoresistance, inhibit the proliferation of tumor cells, and prevent the emergence of metastasis
- Overall prognosis is guarded

337
Q

What is the histologic appearance of canine hepatoid gland tumors?

A

groups of hepatocyte-like cells which in females regress to single islets, whereas in males they form glandular masses

338
Q

What are fibrovascular papillomas?

A

“skin tags” or ACROCHORDONs
Fibrovascular in origin
May be proliferative response to trauma or focal furunculosis
Doberman and lab seem predisposed (large breeds)
Occur over bony prominences
Histopath: filiform to pedunculated, smooth, hyperkeratotic
Surgery vs benign neglect

339
Q

What breed of dogs are predisposed to fibromas?

A

Boxers, Boston terriers, Dobermans, golden retrievers, fox terriers

340
Q

What are the cytologic and histopathologic findings associated with fibromas?

A

FNA – small number of spindle shaped fibroblasts
Histo – whorls of interlacing bundles fibroblasts. May contain mucinous/myxomatous degeneration (fibromyxomas)

341
Q

What are fibropruritic nodules?

A

Etiopathogenesis = unknown
Often seen in dogs >8y in GSD
Solitary/multiple firm/pedunculated alopecic nodules that vary in size 1-2cm
Mainly dorsal lumbosacral area – chronic flea bite
Histo – nodular dermal fibrosis, inflammation, eosinophilic, papillated
Control fleas/surgical excise

342
Q

What is the histopathology of fibrosarcomas?

A

Histo – interwoven bundles of immature fibroblasts, moderate numbers of collagen fibers

343
Q

What are fibromyxosarcomas?

A

fibrosarcomas associated with mucinous/myxomatous degeneration

344
Q

What are myxomas and mycosarcomas

A

Rare neoplasm of older dogs (GSD and Dobermans) and cats from dermal and SC fibroblasts with abundant myxoid matrix with mucopolysaccharides
often infiltrative

345
Q

What is the histopathology of myxomas and mycosarcomas?

A

stellate to fusiform cells in vacuolated basophilic stroma

346
Q

What is nodular fascitiitis?

A

Rare benign, non-neoplastic growth affecting eyes/periocular are (but can occur elsewhere)
Proliferative inflammatory process from SC fascia – often misdiagnosed as a fibrosarcoma
Can be very invasive
Surgical excision is curative

347
Q

What is the histopathology associated with nodular fascitiitis?

A

Histopath – poorly circumscribed proliferation of haphazardly growing fibroblasts with ground substance.

348
Q

What genetic mutation is associated with Schwannomas?

A

Point mutation in HER2/neu oncogene

349
Q

What are clinical signs of Schwannomas caused from?

A

Involve the nerve root as they exit the spinal canal and manifest in pain and paresis due to nerve root compression

350
Q

What are Schwannomas histopathologically characterized by?

A

1) neurofibroma (faintly eosinophilic thin wavy fibres in loosely textured strands
2) neurilemoma – spindle-shaped cells with nuclear palisading and twisting bands with Antoni type A and B tissues

351
Q

What are granular cell tumors?

A

Solitary firm, well circumscribed rare masses within the tongue but can occur in other locations
In cats can be on tongue, vuvla, tonsil, brain and digits
Generally benign and do not metastasize

352
Q

What are granular cell tumors histopathologically characterized by?

A

circumscribed mass of ovioid to polyhedral cells with central or eccentric nuclei and pale cytoplasm containing eosinophilic granules
Granules are PAS, vimentin, and S100 positive

353
Q

What dogs are predisposed to hemangiomas?

A

> 10y
Lightly pigmented Boxers, golden retrivers, GSD, English springer spaniel, Airedale etc.

354
Q

What cat are predisposed to hemangiomas?

A

> 10y
M>F

355
Q

What do hemangiosarcomas stain positive for?

A

Positive for vimentin, S100 protein, Factor 8-related antigen (vWf), type 4 collagen and laminin + CD31 (PECAM)

356
Q

What dogs are predisposed to hemangiosarcomas?

A

Average of 10y in GSDs, goldens, BMDs, and Boxers

357
Q

What tends to cause cutaneous hemangiosarcomas?

A

Chronic solar damage of ventral glarous skin of lightly pigmented dogs and pinna of white eared cats

358
Q

What breeds are predisposed to lipomas?

A

Siames cats, cockers, dachshunds, Weimaraners, Doberman, Mini Schnauzer, Labradors

359
Q

What are the histopathologic features of lipomas?

A

well circumscribed proliferation of normal-appearing lipocytes
Infiltrative lipomas may have a poorly circumscribed proliferation of normal lipocytes that infiltrate surrounding tissues

360
Q

What are liposarcomas?

A

Occur >10y MALES in dachshunds, Shetland sheepdogs, Brittany Spaniels. Solitary > multiple
Malignant, infiltrative, but rarely metastasise
Red O stain for lipid in frozen tissue and to differentiate liposarcomas from other soft tissue sarcomas
Wide surgical excision is treatment of choice (1188 days)

361
Q

What IHNs are cutaneous mast cell tumors positive for?

A

Vimentin, tryptase, KIT (CD117), Chymase, MCP1 and IL-8

362
Q

What factors influence histocyte development?

A

Fms like tyrosine kinase ligand (FLT3)
GM-CSF
Stem cell factor
TNF-alpha
IL4
TGF-b

363
Q

What do Langerhans cells express?

A

E-cadherin
C-type lectin (CD207)
CD1a
CD11c
MHC class II

364
Q

What are interstitial dendritic cells?

A

APCs of the DERMIS
Occur in perivascular locations (except for brain)
Rapid turnover and are repopulated by a blood-borne precursor (monocyte) and by local self-renewal

365
Q

What do interstitial dendritic cells express?

A

Thy-1 (CD90)
CD4
CD1a
CD11c
MHC class II

366
Q

What are Langerhans cells?

A

Antigen presenting cells (APC) of epidermis
Internalization of langerin mediates formation of Birbeck granules
Subject to slow turnover and are maintained by self-renewal or renewal from a dedicated dermal precursor cell
- from CD14+ precursors
- require TGF-B and CCL20
- mature with IL-4 and GM-CSF

367
Q

What markers do macrophages have?

A

class A scavenger receptors
- CD163 and CD 204
display neither E –cadherin or thy-1

368
Q

What CD11s can be found in histiocytes?

A

CD11b – Macrophage + some dermal interstitial cells
CD11c – expressed by LC and interstitial DC
CD11d – Macrophages

369
Q

What immunolabeling is reactive histiocytosis expected to be positive for?

A

CD204, Thy1 (CD90), MHCII, CD1a, CD4, CD18, and CD11c

370
Q

What is responsible for presentation of peptides, lipids, and glycolipids from cutaneous dendritic cells to T cells?

A

CD1a molecules
MHC class I and class II molecules

371
Q

What do splenic histiosarcomas express?

A

CD1a
CD11c
MHC class II

372
Q

What do histiocytic sarcomas of lungs express?

A

CD1a
CD11c
MHC class II

373
Q

What is the marker for the histocyte stem cell precursor?

A

CD34+

374
Q

What happens to CD34+ monocytes under the influence of M-CSF?

A

they become macrophages

375
Q

What happens to CD34+ monocytes under the influence of GM-CSF and IL-4?

A

Become dendritic cells

376
Q

What is differentiation of Langerhans cells critically dependent on?

A

TGF-β1 stimulation
- from epidermal keratinocytes

377
Q

What causes immature epidermal-resident LCs to target the skin?

A

MIP-3α or CCL20 that is produced there?

378
Q

What does successful interaction of DCs and T cells in response to antigenic challenge involve?

A

orderly appearance of co-stimulatory molecules (B7 family – CD80 and CD86) on DCs, and their ligands - CD28 and cytotoxic T-lymphocyte antigen 4 (CTLA-4) on T cells.

379
Q

What breed of dog is prone to multiple histiocytomas?

A

Shar Peis

380
Q

What cells seem to be responsible for the regression of histiocytomas?

A

CD8+ T cells
mediate lysis of neoplastic histiocytes

381
Q

What type of cell do cutaneous histiocytomas seem to arise from?

A

dermal precursors of LCs
do not arise directly from intra-epidermal LCs

382
Q

What Langerhans cell markers fo cutaneous histiocytomas express?

A

CD1a and often E-cadherin

383
Q

What skin homing receptors do T cells express under interstitial dendritic cell influence?

A

CLA/E-selectin
CCR4/CCL17
CCR10/CCL27

384
Q

What do morphological descriptions of histiocytomas emphasize?

A

tropism of the tumor infiltrate for the superficial dermis and epidermis to create a “top-heavy” lesion
- may invade the epidermis as individual cells or nests of cells

385
Q

Which markers do tumor histiocytes in canine histiocytoma express?

A

CD1a
CD11a/CD18
CD11c/CD18
CD44
CD45
MHC class II
E-cadherin
- may be limited to near the surface
+/- CD11b/CD18
+/- CD54

386
Q

What do Langerhans cells use E-cadherin to do?

A

localize in the epidermis via homotypic interaction with E-cadherin expressed by keratinocytes

387
Q

What is cutaneous Langerhans cell histiocytosis?

A

extensive skin involvement with multiple histiocytomas
Shar peis are over-represented
May regress or progress

388
Q

What is a negative prognostic indicator in cutaneous Langerhans cell histiocytosis?

A

Lymphatic invasion
usually progresses to systemic lesions
- ex in lungs

389
Q

What do histiocytic sarcomas tend to be derived from?

A

cells with the phenotypic profile of interstitial DCs

390
Q

Where are interstitial dendritic cells found?

A

occur in all tissue except brain
do occur in the meninges and choroid plexi

391
Q

Abnormalities in which suppressor gene loci have been found in Bernese mountain dogs and flat-coated retrievers with histiocytic sarcomas?

A

CDKN2A/B, RB1 and PTEN

392
Q

What are the clinical signs of histiocytic sarcomas?

A

vague or depend on organ involved

393
Q

What are the typical morphologic features of histiocytic sarcomas?

A

typically destructive mass lesions with a uniform, smooth cut surface and are white/cream to tan in color
composed of sheets of large, pleomorphic, mononuclear and multi-nucleated giant cells, which usually have marked cytological atypia and numerous bizarre mitotic figures
- may consist of spindle cells

394
Q

Which markers do histiocytic sarcomas tend to express?

A

CD1a
MHC class II
CD11c/CD18

395
Q

What does CD4 tend to indicate for histiocytes?

A

an activation phenotype
histiocytes in canine reactive histiocytoses regularly express CD4

396
Q

What do (large cell) lymphocytes express that can make them difficult to tell apart from histiocytes?

A

CD18

397
Q

What are the distinctive syndromes of the histiocytic sarcoma complex?

A

Hemophagocytic histiocytic sarcoma
Articular / periarticular histiocytic sarcoma
Central Nervous System Histiocytic Sarcoma
Dendritic cell leukemia

398
Q

What are the clinical signs of hemophagocytic histiocytic sarcoma?

A

hemolytic anemia, thrombocytopenia
mild hyperbilirubinemia
coagulopathy
seems like IMHA
worst prognosis (MST 4wk)
diffuse splenomegaly
- DCs and macrophages
also in lungs and bone marrow

399
Q

What are the clinical signs of auricular histiocytic sarcomas?

A

multiple tan nodules located beneath the synovial lining
usually has a inflammatory component
associated with CCLrs and trauma
cells are identical to perivascular iDCs
- not synovial fibroblasts

400
Q

What are the clinical signs of central nervous system histiocytic sarcomas?

A

often originates in the leptomeninges
has many mixed inflammatory cells
- an atypical histocytes
Pembroke Welsh Corgis at risk
focal, solitary subdural masses
less common diffuse meningeal infiltrates

401
Q

What is dendritic cell leukemia?

A

a form of histiocytic sarcoma
two reports in dogs
many atypical histiocytes in peripheral blood
DC lineage (CD1+ CD11c+ CD11d- MHCII+)

402
Q

What marker is found on all histiocytes because it is a marker of APCs?

A

CD1a

403
Q

What is the immunophenotypic expression pattern of systemic and cutaneous histiocytosis?

A

markers expected of DCs
- CD1a
- C11c/CD18
- MHC class II
- CD4 (a marker of DC activation)
- CD90 (Thy-1)
negative for E-cadherin

404
Q

Which immunophenotypic involved in histiocytic neoplasms are not assessable in formalin fixed tissue sections?

A

CD1a, CD4 and CD11c

405
Q

What is feline pulmonary Langerhans cell histiocytosis?

A

disease of aged cats (10 to 15 years),
causes progressive respiratory failure
- leading to euthanasia
obliteration of pulmonary parenchyma by infiltrating LCs
- particularly within terminal bronchioles
- Rads: diffuse, broncho-interstitial pattern
- Liver and pancreas spread possible

406
Q

Which breed of dog may be predisposed to the histiocytic sarcoma complex and systemic reactive histiocytosis?

A

Bernese Mountain dogs

407
Q

What is feline progressive histiocytosis?

A

originates from interstitial DCs
Middle aged to older cats
Solidary vs multiple nodules
- focused on head
- may have epitheliotropism
Low-grade neoplasia of iDCs
- initial indolent behavior
But poor long-term prognosis
- spontaneous remission does not occur
- may develop internal lesions

408
Q

What is thought to be the cause of cutaneous and systemic histiocytosis?

A

believed to have an element of immune dysregulation in their pathogenesis
thought to be antigen driven
but no etiologic agent/antigen has been discovered

409
Q

What is the histopathologic appearance of cutaneous and systemic histiocytosis?

A

activated dermal iDCs and T cells
- can be pleocellular
may have lympho-histiocytic vasculitis
lesions radiate from affected vessels and coalesce to form masses, especially in the deep dermis and panniculus
- “bottom-heavy” topography

410
Q

What is cutaneous histiocytosis?

A

involves activated dermal iDCs and T cells
primarily involves skin and subcutis
multiple cutaneous and SC nodules
may wax and wane

411
Q

What is systemic histiocytosis?

A

generalized histiocytic proliferative disease
tendency to involve skin, ocular and nasal mucosae, and peripheral lymph nodes
predominately affects young to middle aged dogs (2-8 years)
clinical signs vary
may have remissions and relapses

412
Q

What neoplasia is readily confused with reactive histiocytosis?

A

Inflamed cutaneous non-epitheliotropic T cell lymphoma
Lymphoma can have variable CD3
- “CD3 antigen loss”

413
Q

What can definitively differentiate between reactive histiocytosis and inflamed cutaneous non-epitheliotropic T cell lymphoma?

A

T cell receptor gamma (TRG) gene rearrangement analysis

414
Q

What stains are lymphangiomas positive for and what can help differentiate them from hemangiomas?

A

positive for
- vimentin
- factor VIII-related antigen(vWF)
- CD31
negative
- laminin
- type IV collagen
absence of continuous basement membrane and pericytes

415
Q

What is malignant fibrous histiocytoma?

A

“grab-bag” diagnosis that includes pleomorphic forms of several soft tissue sarcomas with histologic similarities in horses

416
Q

Which phenotype of nonepitheliotropic cutaneous lymphoma in horses tends to have a long period of stability before progressing?

A

histiolymphocytic phenotype

417
Q

What are pseudolymphomas?

A

disorders in which a histologic picture suggesting lymphoma stands in sharp contrast to benign biologic behavior
associated with reactions to sunlight, drugs, arthropods, contactants, and idiopathy
- usually ticks in horses

418
Q

Which breeds of dog have the highest risk for developing subungual melanomas?

A

Schnauzer family (miniature and standard), Scottish terriers, Irish setters

419
Q

What are the histopathology findings associated with melanomas?

A

characterized by atypical melanocytes in sheets, packets (nests and theques), and cords
The melanocytes may be predominantly epithelioid, spindle cell, or a combination of these two forms.
Rarely, the melanocytic proliferation may be distinctly perifollicular (pilar neurocristic melanoma)
Clear cell (balloon cell) melanomas have been described

420
Q

What are the 5 histologic types of feline melanomas?

A

signet-ring - often amelanotic, thus need to confirm origin from other methods
epithelioid
balloon-cell - often amelanotic, thus need to confirm origin from other methods
mixed epithelioid or spindle
spindle

421
Q

What is a melanoma in the veterinary context?

A

synonymous with a malignant proliferation of
melanocytes

422
Q

What markers can be used to help diagnose melanomas?

A

Melan A, PNL2, TRP-1, TRP-2 combination
in situ hybridization for tyrosine gene
positive for vimentin
variably positive for S-100 protein and neuron-specific enolase
Cyclooxygenase 2 (COX-2) expression
-not normally expressed by melanocyte

423
Q

What is proposed to be the mechanism of action of the dog oral melanoma vaccine?

A

The foreign tyrosinase produced by the vaccine is different enough from canine tyrosinase that it can break tolerance and be recognized by the dog’s immune system as a foreign protein inducing an active immune response leading to destruction of neoplastic melanocytes

424
Q

What are the typical histopathologic findings associated with melanocytomas?

A

melanocytomas are characterized by melanocytes in sheets, packets, and cords.
The melanocytes may be predominantly epithelioid, spindle cell, or a combination of these two forms
Histologic subtypes
- junctional, compound, and dermal
Rarely, the melanocytic proliferation is distinctly perifollicular (pilar neurocristic melanocytoma)

425
Q

Which breed of horse is predisposed to linear epidermal hamartomas?

A

Belgian horses
seen on the caudal aspect of the rear cannon bone areas

426
Q

What are transmissible venereal tumors?

A

Round (or discrete) cell tumor, suspected to be of histiocytic origin
Canids only
may be affected by hormone - ovariohysterectomy can reduce size of tumor
Horizontally transmitted tumor (cellular mechanism of transmission)
Transmitted directly from dog to dog across MHC barriers through transplantation of viable tumor cells on damaged mucosal surfaces
Coitus is the classic mode of transmission - other social behaviors: sniffing, biting, licking, scratching
+/- thrombocytopenia and prolonged clotting times

427
Q

What markers tend to be associated with trichoblastomas?

A

often express p27 in high levels; most express cytokeratin 8 and 18

428
Q

What are the typical histopathologic findings associated with squamous cell carcinomas?

A

Cords of dysplastic keratinocytes within dermis, big keratin pearls

429
Q

What is thought to be the cause of transmissible lymphoma in hamsters?

A

Hamster polyomavirus (papovavirus)
usually T lymphocytes

430
Q

What causes enzootic lymphoma in cattle?

A

retrovirus
(bovine leukemia virus [BLV])

ACVD Exam (25 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions