Cutaneous Neoplasia and Paraneoplastic Syndromes Flashcards

Question

How can energy metabolism differ between normal and neoplastic cells?

Answer 1

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

Answer 2

NF-kappaB and inflammasome signaling

Answer 3

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

Answer 4

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

Answer 5

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

Answer 6

Invasion through the basement membrane

Answer 7

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

Answer 8

hemodynamic shear forces red blood cell collisions immune stresses

Answer 9

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

Answer 10

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

Answer 11

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

Answer 12

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

Answer 13

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

Answer 14

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)

Answer 15

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

Answer 16

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

Answer 17

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

Answer 18

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

Answer 19

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

Answer 20

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

Answer 21

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

Answer 22

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

Answer 23

tumors of mesenchymal origin

Answer 24

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

Answer 25

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)

Answer 26

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

Answer 27

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

Answer 28

extent of spread throughout the body

Answer 29

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)

Answer 30

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

Answer 31

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

Answer 32

mesenchymal cancers

Answer 33

epithelial cancers

Answer 34

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

Answer 35

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

Answer 36

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

Answer 37

development of squamous cell carcinoma

Answer 38

May be associated with multicentric follicular lymphoma

Answer 39

adrenal and other abdominal carcinomas multicentric lymphoma

Answer 40

CD79a and CD20

Answer 41

cytokeratin

Answer 42

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

Answer 43

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.

Answer 44

Spindle, stellate, or oval Cytoplasmic margins are indistinct Often embedded in ECM

Answer 45

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

Answer 46

Exfoliate well (typically)

Answer 47

Exfoliate poorly

Answer 48

Individualized in a monolayer

Answer 49

Exfoliate well

Answer 50

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

Answer 51

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

Answer 52

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

Answer 53

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

Answer 54

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

Answer 55

smooth muscle actin desmin

Answer 56

myogenin D sarcomeric actin desmin

Answer 57

CD1117/c-kit *can be helpful in prognostication

Answer 58

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

Answer 59

CD79a CD20 PAX5

Answer 60

chromogranin A synaptophysin

Answer 61

CD18 CD204 IBA-1

Answer 62

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

Answer 63

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

Answer 64

*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

Answer 65

*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

Answer 66

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

Answer 67

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

Answer 68

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

Answer 69

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

Answer 70

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

Answer 71

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

Answer 72

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

Answer 73

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

Answer 74

a type of RT that utilizes radioactive implants

Answer 75

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

Answer 76

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

Answer 77

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

Answer 78

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%)

Answer 79

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%)

Answer 80

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

Answer 81

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

Answer 82

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

Answer 83

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

Answer 84

M component

Answer 85

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

Answer 86

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.

Answer 87

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

Answer 88

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

Answer 89

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

Answer 90

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

Answer 91

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

Answer 92

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

Answer 93

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

Answer 94

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

Answer 95

particularly on the extremities erythema purpura ulcerations punched out necrosis

Answer 96

Multiple myeloma

Answer 97

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

Answer 98

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)

Answer 99

1. Mast cell tumors 2. Urticaria pigmentosa 3. Diffuse cutaneous mastocytosis 4. Systemic mastocytosis with cutaneous involvement

Answer 100

Cutaneous mast cell tumors

Answer 101

Cutaneous mast cell tumors

Answer 102

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

Answer 103

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

Answer 104

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

Answer 105

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

Answer 106

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

Answer 107

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%)

Answer 108

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

Answer 109

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

Answer 110

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

Answer 111

bulldog descendants

Answer 112

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

Answer 113

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

Answer 114

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

Answer 115

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

Answer 116

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)

Answer 117

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

Answer 118

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

Answer 119

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

Answer 120

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

Answer 121

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

Answer 122

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

Answer 123

associated with the release of eosinophil chemotactic factors

Answer 124

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

Answer 125

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

Answer 126

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

Answer 127

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

Answer 128

Divide them into high and low

Answer 129

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)

Answer 130

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

Answer 131

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

Answer 132

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.

Answer 133

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

Answer 134

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

Answer 135

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

Answer 136

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

Answer 137

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

Answer 138

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

Answer 139

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

Answer 140

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

Answer 141

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

Answer 142

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

Answer 143

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

Answer 144

Mitotic index, multinucleation, and degree of tissue infiltration

Answer 145

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

Answer 146

chemotherapy and/or RT +/- surgery

Answer 147

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

Answer 148

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

Answer 149

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

Answer 150

Subcutaneous MCTs

Answer 151

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

Answer 152

cutaneous - histiocytic and mastocytic splenic/visceral intestinal

Answer 153

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

Answer 154

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

Answer 155

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

Answer 156

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)

Answer 157

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

Answer 158

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

Answer 159

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

Answer 160

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

Answer 161

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

Answer 162

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

Answer 163

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

Answer 164

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

Answer 165

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

Answer 166

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

Answer 167

(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)

Answer 168

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

Answer 169

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

Answer 170

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

Answer 171

Tryptase KIT

Answer 172

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

Answer 173

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

Answer 174

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

Answer 175

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

Answer 176

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

Answer 177

neoplastic lymphocytes are found in the dermis and subcutis

Answer 178

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+

Answer 179

chronic inflammation FeLV may play a role in cats

Answer 180

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

Answer 181

inhibition of PGE2 synthesis

Answer 182

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

Answer 183

tarsus MST of 190 days

Answer 184

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

Answer 185

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

Answer 186

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

Answer 187

English cocker spaniels, boxers, and golden retrievers

Answer 188

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

Answer 189

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

Answer 190

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

Answer 191

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

Answer 192

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

Answer 193

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

Answer 194

face, eyelids, mucocutaneous junctions, elbows, and trunk

Answer 195

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

Answer 196

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

Answer 197

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

Answer 198

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

Answer 199

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

Answer 200

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

Answer 201

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

Answer 202

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

Answer 203

Glucocorticoids

Answer 204

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

Answer 205

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

Answer 206

systemic or topical glucocorticoids or chlorambucil or lomustine

Answer 207

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

Answer 208

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

Answer 209

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

Answer 210

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

Answer 211

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

Answer 212

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

Answer 213

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

Answer 214

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

Answer 215

anemia, microcytosis, elevated alkaline phosphatase activity, and hypoalbuminemia

Answer 216

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

Answer 217

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

Answer 218

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

Answer 219

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

Answer 220

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

Answer 221

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

Answer 222

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

Answer 223

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

Answer 224

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

Answer 225

Cats (classic), rabbits, goats

Answer 226

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

Answer 227

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

Answer 228

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

Answer 229

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

Answer 230

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

Answer 231

CK8, CK15, CK19, and CD34

Answer 232

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

Answer 233

Inferior tricholemmoma Malignant trichoepithelioma Trichoepithelioma Pilomatricoma

Answer 234

IKA isthmic tricholemmoma

Answer 235

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

Answer 236

Trichoblastoma

Answer 237

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

Answer 238

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

Answer 239

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

Answer 240

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

Answer 241

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

Answer 242

surgical excision +/- oral retinoids if many

Answer 243

infundibular keratinizing acanthoma

Answer 244

Afghan Hounds may be predisposed

Answer 245

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

Answer 246

tricholemmomas

Answer 247

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

Answer 248

hair matrix of the hair bulb

Answer 249

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

Answer 250

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

Answer 251

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×

Answer 252

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×.

Answer 253

the primitive hair germ of embryonal follicular development

Answer 254

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

Answer 255

Middle aged (not very geriatric)

Answer 256

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

Answer 257

Ribbon or medusoid Granular cell Trabecular Spindle with ORS differentiation

Answer 258

Ribbon or medusoid

Answer 259

Trabecular

Answer 260

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

Answer 261

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

Answer 262

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.

Answer 263

Bassett hounds - Spayed female dogs may be Persian cats

Answer 264

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

Answer 265

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

Answer 266

surgical excision

Answer 267

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×.

Answer 268

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

Answer 269

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).

Answer 270

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

Answer 271

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

Answer 272

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

Answer 273

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

Answer 274

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

Answer 275

Infundibular follicular cysts Isthmus cysts Matrical cysts Hybrid cysts Panfollicular cysts

Answer 276

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

Answer 277

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

Answer 278

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

Answer 279

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

Answer 280

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

Answer 281

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

Answer 282

Infundibular cyst

Answer 283

Isthmus cyst

Answer 284

Matrical cyst

Answer 285

Hybrid cyst

Answer 286

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

Answer 287

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

Answer 288

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

Answer 289

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

Answer 290

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

Answer 291

axillary and inguinal regions

Answer 292

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

Answer 293

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

Answer 294

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

Answer 295

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

Answer 296

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

Answer 297

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

Answer 298

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

Answer 299

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

Answer 300

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

Answer 301

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

Answer 302

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

Answer 303

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

Answer 304

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

Answer 305

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

Answer 306

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

Answer 307

“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

Answer 308

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

Answer 309

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

Answer 310

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

Answer 311

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

Answer 312

fibrosarcomas associated with mucinous/myxomatous degeneration

Answer 313

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

Answer 314

stellate to fusiform cells in vacuolated basophilic stroma

Answer 315

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

Answer 316

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

Answer 317

Point mutation in HER2/neu oncogene

Answer 318

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

Answer 319

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

Answer 320

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

Answer 321

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

Answer 322

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

Answer 323

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

Answer 324

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

Answer 325

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

Answer 326

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

Answer 327

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

Answer 328

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)

Answer 329

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

Answer 330

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

Answer 331

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

Answer 332

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

Answer 333

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

Answer 334

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

Answer 335

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

Answer 336

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

Answer 337

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

Answer 338

CD1a molecules MHC class I and class II molecules

Answer 339

CD1a CD11c MHC class II

Answer 340

CD1a CD11c MHC class II

Answer 341

they become macrophages

Answer 342

Become dendritic cells

Answer 343

TGF-β1 stimulation - from epidermal keratinocytes

Answer 344

MIP-3α or CCL20 that is produced there?

Answer 345

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.

Answer 346

CD8+ T cells mediate lysis of neoplastic histiocytes

Answer 347

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

Answer 348

CD1a and often E-cadherin

Answer 349

CLA/E-selectin CCR4/CCL17 CCR10/CCL27

Answer 350

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

Answer 351

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

Answer 352

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

Answer 353

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

Answer 354

Lymphatic invasion usually progresses to systemic lesions - ex in lungs

Answer 355

cells with the phenotypic profile of interstitial DCs

Answer 356

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

Answer 357

CDKN2A/B, RB1 and PTEN

Answer 358

vague or depend on organ involved

Answer 359

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

Answer 360

CD1a MHC class II CD11c/CD18

Answer 361

an activation phenotype histiocytes in canine reactive histiocytoses regularly express CD4

Answer 362

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

Answer 363

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

Answer 364

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

Answer 365

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

Answer 366

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

Answer 367

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

Answer 368

CD1a, CD4 and CD11c

Answer 369

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

Answer 370

Bernese Mountain dogs

Answer 371

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

Answer 372

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

Answer 373

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

Answer 374

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

Answer 375

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

Answer 376

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

Answer 377

T cell receptor gamma (TRG) gene rearrangement analysis

Answer 378

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

Answer 379

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

Answer 380

histiolymphocytic phenotype

Answer 381

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

Answer 382

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

Answer 383

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

Answer 384

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

Answer 385

synonymous with a malignant proliferation of melanocytes

Answer 386

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

Answer 387

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

Answer 388

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)

Answer 389

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

Answer 390

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

Answer 391

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

Answer 392

Cords of dysplastic keratinocytes within dermis, big keratin pearls

Answer 393

Hamster polyomavirus (papovavirus) usually T lymphocytes

Answer 394

retrovirus (bovine leukemia virus [BLV])