Cytology of Neoplasia

What are the morphological characteristics of epithelial neoplasia?

cohesively clustered and polygonal cells with distinct cell junctions

What are the morphological characteristics of mesenchymal neoplasia?

individualized arrangement of spindle shaped cells

What are the morphological characteristics of neuroendocrine-appearing neoplasia?

clustered, free nuclei polygonal in shape with indistinct borders

What are the criteria of malignancy?

variation in nuclear morphology

What can enumerate mitotic figures based on tissue architecture?

histopathology not cytopathology

What are examples of variability of nuclear morphology?

anisokaryosis, open chromatin, nucleolar variability, mitotic figures, multinucleated

Are significant nuclear variations only observed neoplastic mesenchymal and epithelial cells?

no caution can be seen in inflammation or recent trauma (reactive fibroplasia)

What are the clinical signs of plasmacytoma?

firm, raised dermal lesion around digits, ears, and mouth that is usually benign

What are the cytologic features of plasmacytoma?

eccentric nuclei, anisokaryosis and multinucleation, paranuclear clearing (golgi), basophilic cytoplasm

What are the clinical signs of mast cell neoplasm?

“the great pretender” can have variable gross appearances

What are the cytologic features of mast cell neoplasm?

abundant fine purple granules that often obscure nucleus of round cells, eosinophils and reactive fibroblast may be observed secondarily ± collagen fibrils

Why is it usually necessary to send off possible mast cell neoplasms?

approximately 10% of MCT granules do not stain with Diff-Quik may confuse with histiocytoma

What are the clinical signs of histiocytoma?

button-like nodules that are smooth, raised, alopecic and commonly ulcerated in dogs less than 3 years old

What are the cytologic features of histiocytoma?

basophilic background with moderate to large amounts of light basophilic, blebbed cytoplasm in “fried egg” round cells sometimes with peripheral clearing ± small lymphocytes

What are the clinical signs of transmissible venereal tumor (TVT)?

external genitalia most commonly affected but can be found around nose, oral cavity, and eyes; most cases in tropical regions

What are the cytologic features of transmissible venereal tumor (TVT)?

punctate cytoplasmic vacuoles in round cells with coarse chromatin in nuclei

What are the cytologic features of follicular neoplasm? (Epithelial neoplasm)

aggregates of anucleated keratinized squamous epithelial cells (keratinocytes) ± inflammation seen as neutrophilic to pyogranulomatous ± necrosis seen as cholesterol crystals

What are the cytologic features of basaloid epithelial neoplasm?

small uniform epithelial cells with high nucleus to cytoplasm (N:C) ratios arranged in “grape-like” clusters

What are the common examples of basaloid epithelial neoplasm?

trichoblastoma (dogs) and apocrine neoplasm (cats)

What are the cytologic features of sebaceous adenoma? (Epithelial neoplasm)

densely clustered cells with small dense nucleus and abundant discrete cytoplasmic vacuolation, may see sebum which appears as amorphous, waxy non-staining material

What are the cytologic features of parianal adenoma? (Epithelial neoplasm)

clusters of cells with amphophilic (lavender) granular cytoplasm with single nucleus with coarse chromatin and 1-2 nucleoli; cells resemble hepatocytes

What are the cytologic features of neuroendcrine-appearing neoplsms?

special type of epithelial neoplasm seen as cell clusters with indistinct cellular junctions and free nuclei in row, gray-blue cytoplasm that may be vacuolated but minimal nuclear atypia (however still act aggressive)

What are palisades?

lined up free nuclei

What are rosettes?

free nuclei arranged in circular pattern

What is an examples of neuroendcrine-appearing neoplsms?

aprocine gland anal sac adenocarcinoma (AGASACA)

What are the cytologic features of squamous cell carcinomas?

tadpole shaped cells with keratinized cytoplasm and nuclear retention (asynchronous maturation) with perinuclear vacuolation, neutrophilic inflammation usually present

What are the cytologic features of transitional (urothelial) cell carcinoma?

clusters of atypical epithelial cells with magenta cytoplasmic inclusion that peripheralizes the nucleus (Melamed-Wolinska body)

What is the most common bladder tumor?

transitional (urothelial) cell carcinoma; seen more often in dogs (trigone or prostatic urethra) than cats

What are the cytologic features of lipoma?

clusters of adipocytes that have a single large vacuole that peripherally displaces a nucleus

What are the cytologic features of soft tissue sarcoma?

highly cellular spindle cells that have elongated tails with wispy borders (veiling); crown cells

What are the most common soft tissue sarcomas?

perivascular wall tumor and peripheral nerve sheath tumor

What are the cytologic features of osteosarcoma?

abundant pink matrix, round to spindle shaped with eccentric nuclei and basophilic cytoplasm with a golgi clearing and visible osteoclasts

What is the most common osteosarcoma?

primary bone tumor in dogs

What are the cytologic features of melanocytoma?

abundant granulated cytoplasm with variably shaped cells; usually cutaneous and benign behavior

What are the cytologic features of melanoma?

abundant pigmented with round, spindle, polygonal cells clustered and individualized, atypical nuclear features; malignant behavior

What are the clinical signs of melanoma?

mass on oral cavity or digits