Internal Medicine and Oncology Flashcards
Hypothyroidism usually result in hairs being arrested in which phase of the hair cycle?
Telogen
What changes occur in hypothyroidism, resulting in the clinical presentation of alopecia and a dry coat?
Sebaceous gland atrophy
Follicular atrophy
What changes to the pinnae might prompt you to evaluate a dog for hypothyroidism?
Pinnal margin seborrhea
A Rhodesian Ridgeback presents with non-pruritic “tiger striping” alopecia. What is a top differential for this?
Hypothyroidism
Besides dogs, what is the only other species known to develop calcinosis cutis secondary to hyperadrenocorticism?
Chinchillas
What makes up the mineral in calcinosis cutis?
Apatite crystals
What 4 dog breeds are predisposed to developing calcinosis cutis?
Labs
Rottweilers
Boxers
Staffordshire terriers
How does hyperestrogenemia cause alopecia?
It inhibits anagen initiation
What digit is often affected in feline lung-digit syndrome?
P3
What type of tumors have been associated with linear preputial hyperpigmentation/erythema?
Testicular tumors (seminoma,
Leydig/interstitial cell tumor,
Sertoli cell tumor)
What tumors have been associated with feline paraneoplastic alopecia?
Pancreatic adenocarcinoma
Bile duct carcinoma
What condition is nodular dermatofibrosis associated with?
Renal cystadenocarcinomas
What is the mode of inheritance of nodular dermatofibrosis in GSDs?
Autosomal dominant
What gene is mutated in nodular dermatofibrosis in GSDs?
FLCN (folliculin)
Besides renal cystadenocarciomas, what neoplastic condition might be seen in intact female GSDs with nodular dermatofibrosis?
Uterine leiomyoma
What underlying causes have been associated with cutaneous xanthomas?
Diabetes mellitus
Megestrol acetate
What breed is predisposed to SLE?
GSD
What dog breeds are predisposed to hypothyroidism (6)?
Dobermans
Beagles
English Setters
Rhodesian ridgebacks
Goldens
Labs
What breeds have thyroid hormone concentrations below the standard reference ranges?
Sighthounds
What is the effects of thyroglobulin autoantibodies on TT4 concentrations?
They falsely increase TT4
You are doing a LDDST on a dog and are using dexamethasone SP for the test. When calculating the dose, what concentration of dex should be utilized?
3 mg/ml
What criteria on LDDST would be consistent with a diagnosis of PDH?
4 hr cortisol < lab cutoff
4 or 8 hr cortisol <50% of baseline
Which test for Cushing’s is less impacted by stress and nonadrenal illness?
ACTH stim
Describe the interpretation of a UCCR for Cushing’s
Negative: HAC very unlikely (high sensitivity)
Positive: HAC not confirmed (low specificity)
What dose of cosyntropin should be given when trying to diagnose HAC?
5 mcg/kg
What is the most common cause of hyperthyroidism in cats?
Benign adenomatous hyperplasia
What serum chemistry abnormalities may be seen in a cat with hyperthyroidism?
Elevated ALT +/- ALP
Azotemia
What subtype of thyroid hormone is most active in the body?
T3
What are the 2 classes of hormone receptors (based on their location in the cell)?
Membrane hormone receptors
Nuclear receptors
Do steroids have membrane hormone receptors or nuclear receptors?
Nuclear (steroid hormones are hydrophilic and can cross the cell membrane)
Do thyroid hormones have membrane hormone receptors or nuclear receptors?
Nuclear (thyroid hormones are hydrophilic and can cross the cell membrane)
What amino acid is essential for thyroid hormone synthesis?
Tyrosine
What enzyme converts T4 to T3/rT3?
iodothyronine deiodinase
What mineral is needed for thyroid hormone synthesis?
iodine
Where it thyroglobulin synthesized?
the thyroid follicular epithelial cell
What happens to thyroglobulin after it is synthesized?
It is secreted into the thyroid follicular lumen
Name the functions of thyroid peroxidase in the synthesis of thyroid hormones
1) Oxidizes iodide ions to I2
2) Iodinates tyrosine on thyroglobulin to produce monoiodotyrosine (MIT) and diiodotyrosine (DIT) (=organification)
3) Coupling of MIT and DIT to produce T4 (2 DIT) and T3 (1 DIT + 1 MIT) on thyroglobulin
Why does the thyroid gland produce more T4 than T3?
Thyroid peroxidase is more efficient at coupling 2 DIT molecules than it is at coupling one DIT and one MIT
What occurs to thyroglobulin once it has been processed by thyroid peroxidase?
It is endocytosed into the thyroid follicular epithelial cell and broken down by lysosomes into T4, T3, MIT, and DIT
What occurs to uncoupled MIT and DIT during thyroid hormone synthesis?
They are transported back into thyroid follicular lumen as iodide
Is most of the thyroid hormone in the circulation protein-bound or free?
Protein-bound to thyroxine-binding globulin (+ albumin, transthyretin)
What form of thyroid hormone has endocrine activity: bound or free?
Free
What organ system produces thyroxine binding globulin?
Liver
What hormone acts directly on the thyroid gland to regulate hormone release and where does the hormone come from?
TSH, anterior pituitary
The thyroid gland produces more T4 than T3. What must occur in target tissues in order to have the endocrine effects of thyroid hormones?
iodothyronine deiodinase in the target tissue converts T4 to T3 (and to rT3)
What is the most important effect of TSH when stimulating thyroid hormone release?
Induces endocytosis of the peroxidase-processed thyroglobulin into the follicular cell (so it can be lysed and made into T4+T3 to be excreted)
What hormone stimulates release of TSH from the anterior pituitary and where does the hormone come from?
TRH, hypothalamus
What provides negative feedback on the anterior pituitary to reduce TSH secretion?
Free T3
What are the regulatory steps in thyroid hormone release?
1) action of free T3 to reduce TSH from anterior pituitary
2) change in ratio of T3: rT3 that is produced by tissue iodinase
What aspect of the nervous system is enhanced by thyroid hormones?
Sympathetic (esp in heart –> increased HR and cardiac outpu)
What is the effect of hypothyroidism on the GIT?
Constipation (thyroid hormone responsible for enhanced GI motility)
What allows for iodide to concentrate in thyroid follicular cells?
Sodium iodide symporter (present on basolateral membrane of thyroid follicular cell)
What allows for iodide to enter the thyroid follicular lumen?
pendrin
What protein allows for T4+T3 to be released into the circulation?
Monocarboxylate transporter 8 (MCT8)
What thyroid hormone is known as thyroxine?
T4
How do glucocorticoids affect thyroid hormones?
Decreased TSH production, decreased iodothyronine deiodinase activity –> less TT4, TT3, fT4, TSH
How does phenobarbital affect thyroid hormones?
Decreased thyroid hormone secretion, increases hepatic metabolism –> less TT4, TT3, fT4
How do NSAIDs affect thyroid hormones?
Displaces T4 and T3 from their plasma protein carriers (mainly aspirin and phenylbutazone; most other NSAIDs do not impact thyroid)
How do sulfonamides affect thyroid hormones?
inhibit thyroid peroxidase –> less thyroid hormone secretion
How do tyrosine kinase inhibitors affect thyroid hormones?
Impair uptake of iodine
Inhibit thyroid peroxidase
Reduce capillaries in thyroid gland
How does amiodarone affect thyroid hormones?
Reduced iodothyronine deiodinase activity
How do TCAs affect thyroid hormones?
Decreased TSH production
Decreased thyroid hormone secretion
What is another name for the pituitary gland?
Hypophysis
What is another name for the anterior pituitary?
Pars distalis
Adenohypophysis
What species lacks thyroxine binding globulin?
Cats
Once T3 is in the cell nucleus, what does it bind to?
Retinoid X receptor (RXR)
What is the pathogenesis of lymphocytic thyroiditis?
Antibodies targeting thyroglobulin
What dog breeds have a familial form of hypothyroidism?
Great Danes
Dobermans
GSPs
What breed is most likely to have a myxedematous coma due to hypothyroidism?
Doberman
What dog breeds tend to have an earlier age of onset of hypothyroidism (i.e. 2-3 years)?
Large/giant breeds
Dobermans
Goldens
A hypothyroid dog begins excessively shedding following initiation of levothyroxine. Why does this occur?
Normalization of the hair cycle –> loss of telogenized hairs
How long does it take for dermatologic abnormalities to respond to thyroid supplementation?
2-4 months
What would be the expected effect of exercise/training on equine T4 and T3?
Decreased
What is another name for growth hormone?
Somatotropin
What gland secretes growth hormone?
Pituitary
What hormones regulate the production of growth hormone and where do they come from?
GHRH, somatostatin
Hypothalamus
What hormones stimulate growth hormone production?
Norepi
Dopamine
Progestogens
GHRH
What hormone inhibits growth hormone production?
Somatostatin
What can be evaluated and serves as an indirect measurement of growth hormone?
Insulin-like growth factor (IGF-1); this protein is stimulated by GH
What dog breeds are predisposed to pituitary dwarfism?
GSD
Karelian bear dog
What is the typical cause of pituitary dwarfism in dogs?
Rathke cleft cysts
When do clinical signs of pituitary dwarfism typically become apparent?
2-3 months of age
A 4 month old GSD is presented with a soft, wooly coat (retention of secondary hairs), symmetrical alopecia, comedones, and stunted growth. IGF-1 levels are dramatically decreased. What is the most likely diagnosis?
Pituitary dwarfism (resulting in reduced GH secretion)
What is the pathogenesis of acromegaly?
Increased growth hormone secretion –> overgrowth of connective tissue, viscera, bone
What is the primary cause of acromegaly in cats?
Pituitary tumor
What is the gender distribution of acromegaly in dogs and cats?
Cats: overwhelmingly male
Dogs: usually intact females
What is usually a comorbidity in dogs and cats with acromegaly?
Insulin-resistant diabetes
What is the hallmark test for acromegaly in dogs and cats?
Measurement of IGF-1 (Growth hormone suppression test hallmark in humans
Besides the anterior pituitary, where else does growth hormone originate in dogs?
Mammary gland
What is the effect of increased IGF-1 on somatostatin?
It increases somatostatin –> reduced GH secretion from pituitary
What is the mode of inheritance of pituitary dwarfism in Karelian Bear dogs and GSDs?
Autosomal recessive
What likely causes the symptoms of lethargy, dullness, and appetite loss in dogs with pituitary dwarfism?
Concurrent deficiency in TSH
What gene is mutated in GSDs and Karelian bear dogs with pituitary dwarfism?
LHX3 (encodes pituitary and nervous system development)
What 4 diagnostic tests can be used to diagnose pituitary dwarfism in dogs?
GHRH stimulation test
Clonidine stimulation test
Xylazine stimulation test
Ghrelin stimulation test
(all should stimulate GH release in health dogs)
What is a common oral cavity symptom associated with acromegaly in cats?
Prognathism of lower jaw
What is the primary cause of acromegaly in dogs?
Endogenous/exogenous progestogens
Define what is meant by the “sensitivity” of a test
Percent of individuals with the disease who test positive
Define what is meant by the “specificity” of a test
Percent of individuals without the disease who test negative
What test for Cushing’s has a higher sensitivity: LDDST or ACTH stim?
LDDST (95% sensitivity)
What test for Cushing’s has a higher specificity: LDDST or ACTH stim?
ACTH stim (64-86% specificity)
What breeds are overrepresented in Alopecia X?
Nordic breeds
Pomeranians
Chows
What is the effect of LH hormone and where does it come from?
Stimulates Leydig cells to increase testosterone production
Comes from anterior pituitary
What is the effect of GnRH and where does it come from?
Increases LH and FSH production in anterior pituitary
Comes from hypothalamus
What hormones have negative feedback to reduce FSH secretion?
Estradiol
Testosterone
Inhibin (from Sertoli cells)
What is the primary cause of canine hypothyroidism?
Lymphocytic thyroiditis
What is the best thyroid monitoring test for a dog known to have thyroglobulin autoantibodies?
FT4 by ED
What is the upper limit of allowable iodine in the diet if treating a hyperthyroid cat with dietary therapy?
<0.32 ppm
What is the primary pathophysiology of HAC in dogs?
Pituitary macroadenoma –> CRH hypersecretion –> adrenal gland hypertrophy
What hormones are deficient in GSDs with pituitary dwarfism (hyposomatotropism)?
GH
TSH
Prolactin
Gonadotropin
What hormone is normal in dogs with pituitary dwarfism?
ACTH
What iatrogenic causes can result in hyperestrogenism in dogs?
Diethylstilbestrol (used for urinary incontinence)
Exposure to human hormone replacers
What physiologic problem is usually the cause of hyperestrogenism in male dogs?
Sertoli cell tumor
What physiologic problem is usually the cause of hyperestrogenism in female dogs?
Cystic ovaries>granulosa-thecal cell tumors
What skin changes can occur with estrous cycles?
Hair loss at the time of estrus
What mutation in MCT allows some of them to be susceptible to tyrosine kinase inhibitors?
C-kit
What IHC stains can be used to highlight canine mast cell tumors?
KIT (CD117)
tryptase
Is the N:C ratio in lymphoma typically high or low?
High (little cytoplasm)
What type of tumors typically appear in clusters of sheets?
Epithelial
Name the major round cell tumors
Lymphoma
Plasmacytoma
MCT
Histiocytoma
TVT
What species commonly develops trichofolliculomas?
Guinea pigs
What dog breed is predisposed to tricholemmomas?
Afghan hounds
What cat breed is predisposed to trichoepitheliomas?
Persians
From what structure are tricholemmomas derived?
Outer root sheath
What dog breeds are predisposed to trichoblastomas?
Poodles
Cocker spaniels
From what structure are pilomatricomas derived?
Follicular bulb
What dog breeds are predisposed to pilomatricomas?
Kerry blue terriers**
Poodles
Old English sheepdogs
Which follicular tumors tend to have a low expression of p27?
Pilomatricomas
Which follicular tumors have a high expression of p27?
trichoblastomas
trichoepitheliomas
What type of sebaceous gland neoplasm is most common in dogs and cats?
Nodular sebaceous gland hyperplasia
What is the recommended treatment for perianal gland adenomas?
Neuter
From what sweat glands are apocrine gland tumors usually derived?
Epitrichial sweat glands
What type of tumors are the most common tumor in pigs?
Melanocytic
What body locations are associated with high rates of metastasis for melanomas?
Digital
Mucocutaneous
Which dog breeds are predisposed to subungual melanomas?
Irish Setters
Scottish Terriers
Schnauzers
A dog with a melanoma has a mitotic index <3. What is the associated prognosis?
Good (>3 is poor prognosis)
What stains could be used to diagnose an amelanotic melanoma?
Melan A
PNL2
TRP-1
TRP-2
What is the primary inflammatory cell infiltrate in fibropruritic nodules?
Eosinophils
What tumor type is often associated with flea allergies in GSDs?
Fibropruritic nodules
What infectious condition has been associated with feline sarcoids?
BPV-14
What type of stain could be used to highlight a firosarcoma?
vimentin
What breeds are predisposed to fibrovascular papillomas?
Large/giant breeds (Dobermans, Labs)
What is the medical term for skin tags?
fibrovascular papillomas
What tumor is more common in cats: hemangioma or hemangiosarcoma?
Hemangiosarcoma
What is a stage 3 hemangiosarcoma?
One that has invaded into the muscle
What is a stage 2 hemangiosarcoma?
One that has invaded into the SQ
What is a stage 1 hemangiosarcoma?
One that is limited to the dermis
How does the body distribution differ for hemangiosarcoma between cats and dogs?
Dogs: trunk and extremities
Cats: Head and pinnae
What type of aggressive vascular tumor is more common in young animals and usually affects the ventral abdomen and limbs?
Lymphangiosarcoma
What cat breed is predisposed to MCT?
Siamese
What breed of dog is usually younger when they develop MCT and may have gross distension of the limbs?
Shar Pei
What is the most common site for feline MCT?
Head
What is the most common site for canine MCT?
trunk > extremities»_space; head
Describe what qualifies as a high-grade MCT using the Kiupel grading system
> 7 mitotic figures/10 hpf
3 multinucleated cells/10 hpf
3 bizarre nuclear/10 hpf
karyomegaly in >10% of cells
What transcription factor is expressed by plasmacytomas?
MUM-1
What is the most common cutaneous tumor in horses?
T-cell-rich B-cell lymphoma
What is the treatment of TVT if spontaneous remission does not occur?
Vincristine
What is the primary tumor in feline lung-digit syndrome?
Metastatic bronchogenic carcinoma
What is the inheritance pattern of dermoid cysts?
Autosomal recessive
What is the mutation in dermoid cysts?
FGF 3, 4, 19
A cat is presented with a cutaneous horn. What diagnostic test should be run to check for an underlying cause?
FeLV testing
Name the 6 types of equine sarcoid
1) Occult
2) Verrucose
3) Nodular
4) Fibroblastic
5) Mixed
6) Malevolent/malignant
Which subtypes of equine sarcoids can transform into fibroblastic types if traumatized?
Verrucose
Nodular
Multiple histiocytic mast cell tumors are identified in a cat. What is the most likely age and breed of this patient?
Siamese
6-8 weeks old (young)
What protein is mutated in canine and feline MCT and SCC?
p53
Which immunohistochemical marker can be used to diagnose MCT?
C-kit
How many tiers are in the Kiupel grading scheme for canine MCT?
2 (high and low)
How many tiers are in the Patnaik grading scheme for canine MCT?
3 (grade 1, 2, 3)
Define a Patnaik grade I MCT
Grade 1: well differentiated, located in dermis and interfollicular spaces
Define a Patnaik grade II MCT
Grade II: rare mitotic figures, infiltration into lower dermis and SQ
Define a Patnaik grade III MCT
Grade III: anaplastic, 1 or more nucleoli, 3-6 mitotic figures/hpf, SQ and deeper invasion
Where on the body would you be more likely to find an aggressive MCT?
Oral/perioral
What is the typical behavior of feline MCT?
Benign
What is the cell that makes up cutaneous histiocytomas in dogs?
Langerhans cell
What dog breeds are predisposed to histiocytomas?
Boxers
Dachshunds
Cocker Spaniels
Great Danes
Shelties
Bull Terriers
What are the most common sites of MCT mets in dogs?
LN
Spleen
Liver
What type of cell predominates in regressing histiocytomas?
CD8+ T-cells
Where are lesions of histiocytic sarcomas usually found?
Extremities close to joint (originating from dendritic cells of synovial lining)
What breeds are predisposed to histiocytic sarcoma?
Bernese Mt Dogs (225x relative risk)
Rottweilers (26x relative risk)
Flat-coated Retrievers (3.7x relative risk)
What markers can be used to help differentiate histiocytic sarcoma from cutaneous reactive histiocytosis?
Histiocytic sarcoma: Low CD4/Thy1 expression
What markers can be used to help differentiate histiocytic sarcoma from histiocytoma?
Histiocytic sarcoma: Low E-cadherin expression
What is the prognosis for histiocytic sarcoma?
Poor - few months even with tx
What cell types make up malignant fibrous histiocytomas?
Fibroblasts
Histiocytic cells
MNGCs
Are feline plasmacytomas usually associated with an underling systemic cause?
Yes - extension from bone and viscera
Are canine plasmacytomas associated with an underlying systemic cause?
No
What IHC stains can be used to diagnose a plasmacytoma?
IgG
Vimentin
CD79a
What breeds have an increased risk of melanocytomas?
Airedales
Bostons
Chihuahuas
Chows
Cocker Spaniels
Dobermans
Mini Schnauzers
Scotties
What IHC stains are positive in melanoma?
Vimentin
+/- S-100, neuron-specific enolase
What has been inserted into the c-myc oncogene and leads to amplified gene transcription in TVTs?
LINE (long interspersed nuclear elements)
What is the most common lesion location for TVT in dogs?
External genitalia (prepuce would need to be retracted in many male dogs to see the tumor)
Cytology from a nodule from the glans penis in a male intact dog from Texas is shown in this image. What is the most likely diagnosis?
TVT
What type of cells make up cutaneous epitheliotropic lymphoma?
T-cells only (CD8+/CD4-)
What type of cells make up cutaneous nonepitheliotropic lymphoma?
B- OR T-cells
What form of cutaneous lymphoma is most common in cats?
Non-epitheliotropic
What is the MST for cutaneous nonepitheliotropic lymphoma?
4-8 months
True or false: Many cats with CETL are FeLV-positive
False (most are negative)
What type of T-cells are usually present in canine CETL?
CD8+, gamma/delta
How does the T-cell infiltrate in canine CETL differ from that in human CETL?
Canine is CD4-/CD8+ predominantly
Human is CD4+/CD8- predominantly
What is the best described topical therapy for CETL in dogs and humans?
Mechlorethamine (Mustargen)
What are the most commonly used protocols to treat CETL?
CHOP (cyclophosphamide, doxorubicin, vincristine, pred)
COP (cyclophosphamide, vincristine, pred)
What is the prognosis for CETL if diagnosed early and treated?
~12 months
What is the prognosis for CETL if diagnosed late (even with treatment)?
4-6 months
What are the 3 forms of cutaneous epitheliotropic lymphoma?
1) Pagetoid reticulosis
2) Mycosis fungoides
3) Sezary syndrome
What are Lutzner cells better known as?
Sezary cells (as seen in CETL- Sezary syndrome)
What is the prognosis for CETL in horses?
Grave
Where are melanomas most commonly found in gray horses?
Perianal region and under tail
What infectious condition has been associated with lymphosarcoma in cows?
Bovine leukemia virus
What % of BLV-infected cattle develop lymphosarcoma?
~5%
What are the 3 forms of lymphosarcoma in cattle?
Juvenile
Thymic
Cutaneous
What is the typical age of onset of melanocytic tumors in cattle?
Young (unlike other animals which tend to have older age of onset)
What is the ligand for KIT on mast cells?
Stem cell factor
What percent of canine MCTs have a C-kit mutation?
15-40%
What breeds are at exceptional increased risk of developing MCTs?
Boxers
Boston Terriers
What is the body site predilection for MCT in Rhodesian Ridgebacks
Tail
What is the body site predilection for MCT in Boxers and and Pugs?
Hind limbs
What is the body site predilection for MCT in Bostons and American Staffordshire terriers?
Hind limbs
What is the body site predilection for MCT in English Setters?
Head and hind limbs
What breeds are more likely to have multiple MCT rather than a solitary MCT?
Weimeraners
Goldens
Shar Peis
Boxers
Pugs
What clinical appearances of cutaneous MCT have been associated with worse prognosis?
Ulceration
Erythema
Pruritus
What breeds tend to have more aggressive forms of MCT?
Shar Peis
Labs
True or false: Chest x-rays are always indicated when a MCT diagnosis is made
False- rarely mets to lungs
What color do mast cell granules stain with H+E?
Gray-blue
Which grade of MCT tends to have poorest granulation?
Grade 3/anaplastic
What IHC markers can be helpful to dx a poorly-granulated MCT?
antitryptase antibodies
chyase
What cell proliferation markers have been used to predict behavior of MCTs?
AgNORs (higher #=worse prog)
PCNA (not correlated with prog)
Ki67 (high expression=worse prog)
Which prognostic factor is independent of histologic grade?
Ki67 expression
True or false: p53 immunoreactivity is associated with survival/recurrence in MCT
False
Which MMPs are secreted by canine MCTs?
MMP 2 + 9
What are the currently recommended surgical margins for cutaneous MCTs?
2 cm lateral and 1 fascial plane deep
What tx provides the best outcome for patients with intermediate-grade and well-differentiated MCT with LN mets?
Sx + radiation
What chemotherapy protocol is commonly used for tx of canine MCT?
Prednisone + vinblastine (+/- cyclophosphamide)
Palladia
What staging should be done for a dog diagnosed with a MCT?
LN aspirates
Abdominal imaging
What phase of the cell cycle do most chemotherapeutics work to treat cancers?
S phase (DNA replication)
How does UV Light lead to cancer?
Formation of thymidine dimers
Is c-kit a proto-oncogene or oncogene?
Proto-oncogene (needs to be mutated to be an oncogene: gain-of-function mutation in exon 8 or 11)
What proto-oncogene serves as a prognostic indicator in canine MCT?
c-kit
What proto-oncogene is mutated in most human cancers?
c-myc
What is the most frequently mutated protein in all human cancers?
p53
What is the function of p53?
It is a tumor suppressor protein - It regulates apoptosis in response to genotoxic or cellular stress
What allows for cancer cells to have replicative immortality?
Telomerase protein - utilized to maintain length of telomeres to continue dividing
What is the Warburg effect?
Aerobic glycolysis in which cancer cells convert glucose to lactate
What is the differentiating step between pre-cancerous neoplasia and malignant neoplasia?
Invasion through the basement membrane
How do sarcomas usually spread and where do they usually met?
Through blood, mets to lungs
How do carcinomas usually spread, ad where do they usually met?
Through blood and lymph, met to lung, spleen, liver, LN
How do round cell tumors usually spread and where do they usually met?
Through lymph, mets to LN, liver, spleen
What is the MOA of cancer caused by papillomavirus?
Viral protein E6 destabilizes p53 and viral protein E7 inhibits pRB (another tumor suppressor protein)
What cancers has papillomavirus been associated with in dogs?
SCC
What cancers has papillomavirus been associated with in cats?
SCC
Bowen’s in situ carcinoma
Viral plaques
Feline sarcoids/fibropapillomas
What is the paraneoplastic syndrome of renal cystadenocarcinoma/leiomyoma in GSDs?
Nodular dermatofibrosis
What is the paraneoplastic syndrome associated with thymoma in cats?
Exfoliative dermatitis
What is the paraneoplastic syndrome associated with pancreatic adenocarcinoma/bile duct carcinoma in cats?
Paraneoplastic alopecia
What is the paraneoplastic syndrome associated with pancreatic glucagonoma?
Superficial necrolytic dermatitis
What is the paraneoplastic syndrome associated with multicentric lymphoma or adrenal tumors in cats?
Skin fragility syndrome
What is the paraneoplastic syndrome associated with multicentric follicular lymphoma in cats?
Bilateral ischemic necrosis of the hind paws
What type of cells are highlighted using vimentin?
Mesenchymal
What type of tumor are melanocytic tumors?
Mesenchymal
In what case would you use toluidine blue or Giemsa stain on a tumor?
To highlight mast cell granules
In what cases would you use Fontana Masson on a tumor?
To highlight melanin in lightly pigmented melanomas
What IHC marker is used for carcinomas?
Cytokeratin
What IHC marker is used for sarcomas?
Vimentin
What IHC markers are used for hemangiosarcomas?
Factor VIII-related antigen
Claudin 5
CD 31
What combination of IHC markers are used for melanomas?
melan-A
PNL2
TRP-1
TRP-2
+/-S100
What IHC markers are used for skeletal muscle tumors?
myogenin D
sarcomeric actin
desmin
What IHC markers are used for smooth muscle tumors?
smooth muscle actin
desmin
What IHC markers are used for mast cell tumors?
CD117/c-kit
What IHC marker is used for plasma cell tumors?
MUM1
What IHC marker is used for T-cell lymphoma?
CD3
What IHC markers are used for B-cell lymphoma?
CD79a
CD20
PAX5
What IHC markers are used for neuroendocrine tumors?
chromogranin A
synatophysin
What IHC markers are used for histiocytomas?
CD18
CD204
IBA-1
Would you expect a reactive process to be polyclonal or monoclonal on PARR?
Polyclonal
Would you expect a neoplastic process to be polyclonal or monoclonal on PARR?
Monoclonal
What type of cells can PARR be performed on?
Lymphoid cells only
What types of cancers is imiquimod useful for?
actinic keratoses
SCC
What species has a higher prevalence of malignant skin tumors?
Cats
What are the top 4 skin tumors in cats?
Basal cell tumors
MCT
SCC
Fibrosarcoma
You see the cell shown on cytology from a solitary, smooth, pink mass on a dog. What is the name of the cell in the photo and what tumor is it associated with?
Mott cell (containing Russell bodies)
Associated with plasma cell tumors
What bloodwork/UA parameters should you pay attention to in a patient with a plasma cell tumor?
Renal parameters
Serum calcium
On what part of the body are plasmacytomas usually found in dogs?
Limbs
Head
Where do mast cells mature?
In the tissue (released from bone marrow as precursors)
Describe the paraneoplastic syndromes associated with MCTs?
1) Darier’s sign (degranulation due to manipulation)
2) GI ulceration (due to histamine binding to H2 receptors)
3) Coagulation abnormalities (due to heparin release from granules)
4) Delayed wound healing
5) Hypotension
6) Hypereosinophilia
What should you tell the owner about the prognosis for a dog diagnosed with a grade 3 MCT?
Prognosis poor- most dogs die from disease within a year
What body locations carry a worse prognosis for MCT?
Subungual
Oral/mucous membrane
Preputial
Scrotal
True or false: SQ MCT tend to have a better prognosis
True
What dog breeds have a better prognosis for MCT?
Boxer/other brachycephalic
What type of MCT is not accurately prognosticated with the Kiupel/Patnaik grading systems?
SQ
Name 3 chemotherapy protocols for treatment of canine MCT
1) Prednisone
2) tyrosine kinase inhibitors (Palladia, Masivet, Gleevec)
3) Stelfonta
Stelfonta is indicated for which types of MCT?
Non-met SQ MCT on DISTAL LIMBS
Non-met cutaneous MCT anywhere on the body
What 3 MCT presentations are present in cats?
1) Cutaneous
2) Splenic/visceral
3) Intestinal
What are the 2 subtypes of feline cutaneous MCT?
1) Histiocytic
2) Mastocytic
What subtype of feline cutaneous MCT typically appears at a younger age?
Histiocytic subtype (esp Siamese)
What is the typical age of onset of urticaria pigmentosa?
Young (often <1 year)
What cat breeds are predisposed to urticaria pigmentosa?
Sphynx
Devon Rex
A cat is presented with cutaneous lymphoma affecting the tarsi. What is the likely prognosis?
Poor – this area tends to be associated with an aggressive subtype of non-epitheliotropic lymphoma
What is the MST for CETL in dogs?
6 months (few mo-2 yr)
What type of lymphocyte is associated with a better prognosis in non-epitheliotropic lymphoma?
B-cell (important to do immunophenotyping)
What type of T-cells are usually present in canine cutaneous lymphocytosis?
alpha/beta T-cells (this differentiates it from CETL)
What organ is usually involved in lymphoid granulomatosis?
Lung
What dog breeds are predisposed to multiple IKAs?
Norwegian elkhounds
Lhasas
Keeshonds
What dog breeds are predisposed to multiple trichoepitheliomas?
Basset hounds
English springer spaniels
What cell lineage is histiocytic sarcoma derived from?
Interstitial dendritic cells
What marker is expressed by Langerhans cells and can be assessed on formalin-fixed tissue?
E-cadherin (they also express CD1a but this cannot be assess on formalin-fixed tissue)
What infectious disease has been associated with SCC development in cats?
FIV
What is the most common neoplasia of the digit?
SCC
What dog breeds are predisposed to multiple digital SCC?
Giant Schnauzers
Large black dogs (Rottweilers, Standard Poodles, Black Labs, GSDs)
What marker can be used to identify SCC?
cytokeratin (carcinomas are cytokeratin +)
What is the typical behavior of SCC?
Locally invasive, slow to met (exception- digital SCC)
True or false: Subungual SCC has a better prognosis than SCC elsewhere on the digit
True
What is a cat with FeSV-induced fibrosarcoma going to test positive for?
FeLV (FeSV is a mutant of FeLV)
What is the most common hair follicle tumor in dogs?
Trichoblastoma
What HF neoplasms express cytokeratin 15?
trichoblastomas
trichoepitheliomas
tricholemmomas
Expression of cytokeratin 15 in HF neoplasms suggests they originated where?
From follicular stem cells
What markers can be used to differentiate basal cell carcinomas from trichoblastomas?
SOX9
LGR5
LGR6
(all are higher in trichoblastomas)
What marker is variably expressed in all HF tumors?
SOX9 (strongest in trichoblastomas)
What dog breed is particularly predisposed to develop IKAs?
Norwegian Elkhounds
A HF tumor from a dog reveals a cyst wall consisting of squamous, stratified epithelium with keratohyalin granules. What part of the HF did the tumor originate from?
Infundibulum (KH granules)
From what part of the HF do tricholemommas originate?
Isthmus
What are the two types of tricholemmoma?
Isthmic type
Inferior/bulb type
From what part of the HF do trichoblastomas originate?
Hair germ
True or false: Trichoblastomas are frequently pigmented
True
What is the typical body region distribution for trichoblastomas in dogs and cats?
Dogs: Head and neck
Cats: Head and cranial trunk
What are the 5 subtypes of trichoblastomas?
1) Ribbon/medusoid (most common in dogs)
2) Trabecular (most common in cats)
3) Spindle
4) Trichoblastoma with ORS differentiation
5) Granular cell
From what part of the HF are pilomatricomas derived?
Inferior portion (matrix of hair bulb)
What HF tumors arise from all 3 portions of the HF?
Trichoepitheliomas
Trichofolliculomas
What breeds are predisposed to dermoid cysts?
Rhodesian Ridgebacks
Boxers
What dog breeds are predisposed to follicular cysts?
Boxers
Shih Tzus
Mini Schnauzers
Basset Hounds
Old English Sheepdogs
From what part of the HF are matrical cysts derived?
Inferior portion
Ghost cells are consistent with HF tumors arising from what part of the follicle?
Inferior portion
True or false: Oral lesions are common in cats with CETL
False
True or false: CELT in cats often involves infiltration of adnexal glands
False (UNLIKE dogs)
What dog breeds are predisposed to nodular sebaceous hyperplasia?
Poodles
Cocker Spaniels
Manchester Terriers
Wheaten Terriers
What is the inheritance pattern for pituitary dwarfism?
Autosomal recessive
What viral disease has been associated with SCC in horses?
Equine papillomavirus-2
What horse breed is predisposed to getting SCC on eyelid and sclera?
Paint