Path- Lab- Tumors 1

dpearce's version from 2017-03-05 23:18

Squamous cell carcinoma/ nail bed tumors

Question Answer
Where does a SCC occur in the horse?PENIS, Eyelid
Where does a SCC occur in the cat?Tongue, Skin
Where does a SCC occur in the dog?Gingiva, Skin
Where does a SCC occur in the horse/pig?Non-glandular stomach
Where does a SCC occur in the cattle?Rumen, EYE
Cutaneous squamous cell carcinomas occur in who?Common in DOG & CAT
Where are the 3 origins of SCC?Epidermis of skin
Hair follicle
Stratified squamous epi of mucosal surfaces
What is the etiology (cause) of SCCs?SOLAR RADIATION, esp in areas without pigment (in cats, virus)
What should we know about dermoids?ARENT NEOPLASMS (Non-neoplastic, normal, mature tissue in an abnormal site)
Who do nail bed tumors usually occur in?Dogs & cats
What are the 3 nailbed tumors?Subungual keratoacanthomas
Subungual SCCs
Subungual Malignant Melanomas
Subungual keratoacanthomas occur in what parts of the tissue? Is it benign or malignant?Benign. Corneum & lucidum only (top layers. hence keratinized. carrots cant hurt you! = benign)
Subungual squamous cell carcinomas occur in what parts of the tissue? Is it benign or malignant?Malignant. Includes/extends into basal layer. P3 (the bone) lysis can occur ("SCC down to P3")
Subungual malignant melanomas occur in what part of the tissue? What can occur?Melanocytes in basal layer. P3 (bone) lysis can occur
Explain the histological appearance of SCCs (where are the layers, what do you see? why does it look like that?)Islands are observed w/ basal cell layer on outside w/ stratum corneum in center = Keratin pearl (hyaline red). This occurs bc tumor infiltrates tissue- pushes corneum inward


Question Answer
What are PAPILLOMAS?Benign neoplasm of stratified epithelium- multicentric (many different sites at the same time)
Where do papillomas occur in the YOUNG horse?Lips
If you see a sarcoid on a horse, what do you think happened? (Where would you see them?) How would you describe the epidermis?It might be bovine papilloma virus in a horse (penis, lips, & eyes). Hyperkeratotic & acanthotic (thickening of squamous cell layer) epidermis
Where do papillomas occur in the dog?(Young dog usually) ORAL or CUTANEOUS. ETIOLOGY (cause) of each form is SITE SPECIFIC
What kind of papilloma would you see on a YOUNG cattle? How about age-irrelevant?FIBROPAPILLOMA. Young = PENIS OF YOUNG BULL (& vagina of heifers). Otherwise = skin
Where would you find a papilloma on a cat?NO PAPILLOMAS FOR CATS
What is the etiology of papillomas?VIRAL etiology, species-specific viruses
What does the histology of a papilloma look like?Center is CT from dermis outside is squamous cells (with marked hyperkeratosis) bc papilloma grows OUTWARD (why it’s all Horney on the outside)
Pathology of papilloma (gross appearance)Cauliflower-like, single or multiple (...looks like a wart)
On who do you find fibropapillomas?Develop on the penis of young bulls & on vaginal mucosa of heifers. (fibroelastic penis in bulls! so fibro! & bulls! penis!)

FIBROMA/FIBROSARCOMA (from fibrous connective tissue)

Question Answer
What is more common, a fibroma or a fibrosarcoma?Fibrosarcoma → (sadface. remember that there is a feline sarcoma virus & you'll remember which is more common)
Where do fibrosarcomas usually occur on cats? What are the 3 possible causes?Important bc KNOWN etiology! Usually occur on trunk/extremities
(1) Virus induced → feline sarcoma virus!!! FeLV also contributes → Oral cavity
(2) Non-virus induced - inflammation trauma → older cats
(3) Vaccine assoc- from adjuvant - very aggressive
What do you want to know about vaccine-associated fibrosarcoma in cats? (Cause, preventative measures?)From ADJUVANT in vx. Vx at DISTAL TIBIA for easy amputation
What does the histology of a fibrosarcoma look like?Pleomorphic fibroblasts
Where do fibrosarcomas usually occur in dogs? (3 places & possible etiologies)(1) Usually on trunk & extremities. Can be in association with the parasite SPIROCERCA LUPI (I tried to eat a spirocerca lupi, but it was very fibrous)
(2) Oral cavity- periosteum of maxilla & mandible
(3) Bone

Lipoma/Liposarcoma: Adipose cells

Question Answer
Can you/how can you tell lipomas & liposarcomas apart?Clinically indistinguishable- sarcomas are RARE. Histo will differentiate the 2 (sarcoma is anaplastic)
Where do lipomas occur in cats?Skin
Where do lipomas occur in dogs?Skin of trunk & limbs
Where do lipomas occur in horsesTumors adipose cells of mesentery = DEATH through bowel strangulation
What is the gross appearance of a lipoma/liposarcoma?Soft, greasy, encapsulated, white/yellow
What is the microscopic appearance of a lipoma/liposarcoma?Pleomorphic (variable size/shape) cells, sarcoma exhibits anaplasia
How dangerous are lipomas?Benign, not USUALLY a huge HORSES it's a big deal bc they occur on the mesentery & can cause BOWEL STRANGULATION


Question Answer
Which cells do histiocytomas arise from?From histiocytes (macrophages) (Langerhans cells) in SKIN
What is unusual about a histiocytoma?Fast growing but benign
Who are histiocytomas common in?DOGS (all the pictures were dogs. also That Dawg sure liked Histo!)
What is the gross appearance of a histiocytoma?Solitary, dome shaped, bright red, grow rapidly,”BUTTON” tumor bc depressed in center from necrosis (histio pushed his buttons--- NOT THE WED WON)
What is the microscopic appearance of a histiocytoma?(Macrophages) Round to polygonal cells, arranged in cords or solid sheets (histo is a class that had many shaped cells, round or polygonal, & you could learn with cords, aka comps, or sheets, aka paper)

Clonally transmissible tumors → the only known naturally occurring clonally transmissible cancers

Question Answer
Classic example in an exotic species of this?Tasmanian devil facial tumor
Transmissible Venereal Tumor (TVT) occurs in who? Where?Dogs → penis/prepuce, vulva/vagina
What is the origin of TVT?Not well known...possible macrophages (Mac watching TV)
What does the histology of TVT look like?Large nucleus- cytoplasm is like thin ring w/ vacuoles, boundary of cell NOT clear
How does TVT spread? What kind of invasiveness is it?Locally invasive, spreads during mating via graft
Where is there a high incidence of TVT?Temperate areas & monger dogs
How is TVT spread?Transmitted to new location in the body (often during mating), where it grows as graft.
How invasive is it?Locally invasive, Metastasis reported in about 3% cases.

Melanocytoma & Melanoma

Question Answer
Melanocytoma/melanoma → which is malig & which is benign?Cytoma = Benign. Oma = MALIG ← UNUSUAL SUFFIX!!
Where are the 2 places that melanocytomas/melanomas occur in the DOG (which is benign/malig)(1) SKIN → melanocyte → benign
(2) Muco-cutaneous junction → MALIGNANT → melanoma
Which type of horses get melanocytomas/melanomas (which one)? Where?GREY Horses → Peri-anal & perineum at base of tail (metastasize to pelvic & peri-rectal lymph nodes) = MALIGNANT- melanoma
Aside from dogs & horses, what other animal gets melanocytomas/melanomas (which one)? Where?MINIATURE PIGS

Mast cell tumor (MCT)/ mast cell sarcoma/mastocytoma

Question Answer
Where do MCTs occur in DOGS? Size? Clinical signs? Histo?SKIN most common site, can be small to large
Histo: Mast cells & eosinophils USUALLY present
Clinical signs caused by histamine:
GI ulcers
Where to MCTs occur in CATS? (2) Clinical signs for each?(1) Cutaneous- Clinical signs: edema of limbs, pruritic papillocrustus all over body, lymphadenopathy (huge LNs)
(2) Visceral → SPLEEN (most common abnormality of feline spleen). Clinical signs: small ulcers in stomach & duodenum- hyperhistaminemia (MASTS JABBING THROUGH A CATS SKIN & INTO ITS SPLEEN)
How can you tell a MCT from another round cell tumor?Their blue purple granules stained with Wright or Giemsa stain, OR if poorly granulated, special stain Toluene blue

Lymphosarcoma/ Lymphoma= MOST common neoplasm in animals!!!!!!!!!!!!!!!!!!!!!!!

Question Answer
What are the different types of lymphosarcomas/lymphomas CATS get? What is the etiology?Etiology = FeLV & FIV → hemopoietic tumors (90% of hemopoietic tumors in cats are lymphosarcomas)
MOST COMMON type is alimentary, there is also a mediastinal (NOT hypercalcemia, unlike dog), multicentric, & extranodal form. (If you're a cat, a LN full of retroviruses is yummy!)
What are the different types of lymphosarcomas/lymphomas DOGS get? What is the etiology?Etiology = NO VIRAL ETIOLOGY
MOST COMMON type is MULTICENTRIC(mult LNs)*HYPERCALCEMIA*. There is also alimentary, mediastinal*HYPERCALCEMIA, cutaneous, extranodal (dogs love calcium so much they put it in their MULTIPLE LNs apparently, also sometimes their heart <3 bc they love it)
What are the different types of lymphosarcomas/lymphomas CALVES/CATTLE(differentiate the age on these) get? What is the etiology?Types = CALF (young), THYMIC (young), SKIN (young), ( ← these 3 not contagious, deemed "sporadic") & Enzootic leukosis → BLV. Mature cattle- can occur anywhere in body (cattle LNs are scrutinized all the time, & age matters! 3 baby LNs & then a virus if you're an old cattle)

Plasma cell tumor- B cell tumor

Question Answer
Cutaneous plasmacytoma → occurs in who? How often? How invasive?(Usually old) Dogs → non-invasive
(Bitches get B on the skin...but it wont do much there)
Extramedullary plasmacytoma → occurs in who? Where? How invasive?Old dogs
Rectal mucosa, assoc w/ amyloid, metastatic (old bitches get the B in the BUTT...not in the bone, so extramedullary)
Multiple Myeloma → occurs in who? Where? How common?RARE, but MOST SPECIES are affected. Assoc w/ neoplasm in BONE MARROW
How can you diagnose multiple myeloma?Bone lysis, & More than 30% plasma cells in BM
What are the clinical signs of multiple myeloma?Lameness
Renal dz


Question Answer
Which cells are affected in a hemangiosarcoma? Is it benign or malignant?Endothelial cells lining bvs, highly malignant
How common is hemangiosarcoma in dogs? Where does it usually occur? What are the clinical signs?Common in dogs, usually in the SPLEEN! Clinical signs are sudden collapse bc rupture of tumor (lots of blood vessels in the dog spleen...lots of chances to die. also note that hemangiosarcoma in dog spleen, but in cat spleen it's MCTs)
How common is hemangiosarcoma in cats? Where does it usually occur?Less common, in skin (cats won this round over dogs → a bunch of BVs in your skin is no big deal.)
What happens if there is a hemangiosarcoma in the bone?It is VERY destructive, which is why one of the clinical signs can be LAMENESS (blood exploding out of the bone & shattering it)

Mammary gland tumor

Question Answer
Mammary gland tumor in bitches → how common? Where is it usually located? Is it benign or malignant?MOST COMMON TUMOR OF BITCHES. caudal 2 glands most affected. 50% benign, 50% malignant
How can you help prevent a mammary gland tumor in a bitch/queen?Ovariectomy - decreased risk if spayed before 1st & 2nd heats
Mammary gland tumor in queens → where is it usually located? Is it benign or malignant?CRANIAL 2 glands affected. >90% malignant


Question Answer
Arise from what cells?Epithelial cells (glands live in epithelium)
In adenoma/adenosarcoma which areas of the body are affected?GI tract
Genital tract
Gall bladder
Mammary gland
Nasal passages
Eye lids & other tissues with epithelium (epithelium is where glands live)
Which animals are affected by adenomas/adenocarcinomas?All species
Morphology of the tumorTumor may be papillary, tubular, acinar & mucinous. Sometimes more than one is in one single neoplasm.
Adenocarcinoma/adenoma of uterus → occurs in who?Rabbits & CATTLE!!
IN CATTLE what kind of adenoma/adenosarcoma?Adenocarcinoma of uterus is 2nd most common occurring neoplasm after lymphoma
What should you know about rabbits & adenoma/adenosarcomas?Adenocarcinoma OF UTERUS constitutes the single most common neoplasm in this species.

Anal gland adenocarcinoma

Question Answer
Anal gland adenocarcinomas arise from what structure of the body?Arise from apocrine sweat/sebaceous glands
Anal gland adenocarcinomas occur in what animal?Dogs
Clinical signs of an anal gland adenocarcinoma?*Hypercalcemia* bc tumor secretes parathormone-like substance


Question Answer
Hepatiods/perianal gland tumors arise from what body structure?Modified sebaceous glands (hence greasy appearance)
Are perianal gland tumors benign or malignant? What animal do they occur in?>90% benign, dogs (it's bad enough it's orange & greasy, might as well cut them a break & let it be benign)
Gross appearance of perianal gland tumors?Orange-tinged & greasy (around the dogs butt was a greasy orange lump...ew)
Microscopic appearance of perianal gland tumors?Polyhedral (3D shape with flat faces) cells resemble liver

Sertoli cell tumor

Question Answer
Where does a sertoli cell tumor occur? Is it benign or malignant? Which animal is it most common in?In testes- mostly benign- in DOGS (bad enough their balls have cancer-- at least let it be benign)
What is the condition/clinical signs of a sertoli cell tumor?Hyperestrogenism → feminization & BM depression! Clinical signs: gynecomastia, hyperpigmentation, alopecia, sexual attraction to other male dogs

Granulosa cell tumor

Question Answer
Where do granulosa cell tumors occur?In Ovaries (ovaries full of grains)
In which animals are granulosa cell tumors mostly benign? What are the side effects?Cows & mares, causes masculinization (horses & cattle are MANLY ANIMALSSS as compared to dogs & cats, even the female mares & cows. but they WILL NOT DIE bc of their MANLY DETERMINATION)
In which animals are granulosa cell tumors mostly malignant? (Metastasis will occur)Queens & bitches (dogs & cats just have all sorts of problems with their naughty bits---& it's malignant)