L3: Epithelial And Neuroendocrine Flashcards
Chars. Of epithelial neoplasms
- readily exfoliate
- cohesive clusters and sheets
- have distinct cytoplasmic borders w/ membranes adherent to each other displaying tight cell junctions (desmosomes)
- round, oval, or polygonal cells
- acinar (glandular) formation
- usually met via LYMPHATICS if malignant
Criteria of malignancy for epithelial neoplasms
- nuclear features can be a reliable indicator usually
- histopath may be required for dx in mammary and hepatocellular tumors
Hepatocellular carcinoma
- a type of epithelial tumor
- required histopath for accurate dx
- cells look normal on cyto, but malignant on histopath
- most commonly in left lateral liver lobe
Epithelial neoplasia nomenclature
Benign: oma, adendoma (glandular); ie. Sebaceous epithelioma
Malignant: carcinoma or adenocarcinoma (glandular); ie. Squamous cell carcinoma
Most common tumor in the dog
Adnexal tumors (arise from the hair follicles)
-most common single type of tumor = mast cell tumor
Cutaneous adnexal neoplasms chars.
- type of epithelial neoplasm
- used to be called basal cell tumor
- most common cutaneous tumor of the dog and cat**
- Site predilection: head and neck
- most are benign
- tightly adherent clumps of deeply basophilic epithelium
- high N:C ratio
- melanin pigment may be present (black, rod-shaped granules)
- occasional nucleoli may be seen
- can have sebaceous or follicular differentiation
Chars. Of Apocrine gland tumors
- type of epithelial tumor
- arise from sweat glands
- cuboidal to polygonal cells
- cells may contain pigment
- mostly benign (70%)
- exfoliate in sheets and clumps
Types of apocrine gland tumors
Apocrine adenoma Apocrine carcinoma Ceruminous gland adenoma -common in cocker spaniels and shih tzu Ceruminous gland carcinoma -common in cocker spaniels and cats -almost always malignant in cats -50/50 malignant in dogs
Chars. Of sebaceous gland tumors
- type of epithelial tumor
- arise from sebaceous glands
- polygonal cells with finely vacuolated cytoplasm
- typically have low N:C ratio
- grossly looks warty and pedunculated
- types: sebaceous adenoma, sebaceous epithelioma, sebaceous carcinoma
Two types of perianal neoplasms
1) circumanal gland (hepatoid)
- epithelial
2) Anal sac apocrine gland
- neuroendocrine
Chars. Of circumanal gland neoplasms
-aka “perianal gland adenoma” or “hepatoid tumor”
-looks similar to hepatocytes
cytologically
-arise from modified sebaceous glands in dogs (ie. Perianal, thigh, tail, dorsum)
-most are benign
-most common in older intact male dogs
-surgical excision typically curative
-recurrence possible (androgen driven), so should neuter!
Cytological appearance of circumanal gland neoplasms
- clusters of large, polyhedral hepatoid appearing cells w/ pink hued abundant basophilic cytoplasm
- round to oval nucleus with clumped chromatin and 1 or 2 prominent nucleoli
- smaller “reserve cells” may also be present with higher N:C ratio along the periphery
Distinction b/w circumanal gland adenoma and adenocarcinoma
- may require histopath
- most tumors in intact males benign
- some tumors in females and neutered males may be malignant and can met to regional LN
Chars. Of anal sac apocrine gland adenocarcinoma
- malignant apocrine gland (epithelial) tumor
- common in older dogs
- mets to sublumbar LN
- can cause hypercalcemia
- tumors may be very small but can met at any size
- clumps or sheets of epithelium with indistinct cell borders
- cells appear lysed or “neuroendocrine”
- high N:C ratio with fairly uniform nuclei
- indistinct nucleoli
Test for hypercalcemia of malignancy
Increased parathyroid hormone related protein (should normally be 0)
Chars. Of mammary neoplasms
- can be non-neoplastic (ie. Hyperplastic nodule) or neoplastic (ie. Adenoma or adenocarcinoma)
- tissue architecture necessary to differentiate
Incidence of mammary tumors
Cats: 3rd most common neoplasm
Dogs: 2nd most common
- Rare in horses, cattle
- can occur in males
- usually malignant in mice but benign in rats
Biologic behavior of mammary tumors in cats
- 85-93% malignant
- increased risk in Siamese cats and DSH
Biologic behavior of mammary tumors in dogs
- 41-53% malignant
- familial in Beagles
- increased incidence of malignancy in poodles, dashshunds, spaniels
Most common sites of distant metastasis of mammary tumors
- Inguinal, sublumbar, sternal, axillary, prescap LN
- LU, LIV
- rarely bone
Which LN drains the head and rostral oral cavity?
Submandibular
Which LN drains the caudal head (pharynx, part of pinna), most of thoracic limb, and part of thoracic wall:
Prescapular LN
Which LN drains the thoracic wall, deep structures of the thoracic limb and neck, and thoracic and cranial abdominal mammary glands?
Axillary
Superficial inguinal lymph node drains what areas?
- Caudal abdominal and inguinal mammary glands
- ventral half of the abdominal wall
- penis
- prepuce and scrotal skin
- tail
- ventral pelvis
- medial side of the thigh and stifle
Popliteal LN drains what area?
All parts distal to the node
Birds and reptiles don’t have LN
:)
Chars. Of squamous cell carcinoma
- most common malignant epithelial tumor of the oral cavity
- common sites in SA: palate, lip, cheek, gingiva, tongue, tonsil, ears, nose, digits
- common sites in LA: eyes, penile/vulvar
- appears like an epithelial neoplasm with some squamous differentiation
- aggressive and invasive, esp. In cat
- tumors at base of tongue, tonsil, and digits readily met to regional LN
Cytologic appearance of SCC
- angular cytoplasmic borders
- dysplasia w/ inappropriate keratinization (appears blue): asynchrony of maturation
- small, perinuclear vacuoles
- some mature squamous cells
- often inflamed
- keratohyalin granules (a mature change) - look light pink/purple
Which is better, FNA or imprint
FNA
Categories of Neoplasia
Epithelial
Neuroendocrine
Mesenchymal
Round cell
