Cutaneous mass aspirate from a Golden Retriever: “glandular guile”

Abstract

A 3-year-old, neutered male Golden Retriever was presented to the University of Wisconsin-Madison Veterinary Medical Teaching Hospital (VMTH) for evaluation of a cutaneous mass located over the left cranial thorax. The mass was an incidental finding by the owner, and its duration was unknown. The dog had been presented to the VMTH twice in the previous year: once for elective castration and once for a single episode of diarrhea. No cutaneous masses had been found during the previous physical examinations.The mass was 10 3 9 3 5 mm and was firm, non-ulcerated, red, raised, and nonpruritic. Regional lymphadenopathy was absent, and there were no other clinical signs. Fine-needle aspiration of the mass was performed, and the specimen was submitted for cytologic evaluation (Figure 1). Based on the cytologic findings, thoracic radiographs were taken, and excisional biopsy of the mass was performed.(Continued on next page) Figure 1. (A-C) Three areas from a fine-needle aspirate of a cutaneous mass from a dog. Modified Wright's, 360 objective.The sample was highly cellular with large numbers of pleomorphic, individualized, round to polygonal cells having variable N:C ratios (Figure 1). Anisocytosis and anisokaryosis were marked. Cell margins typically were distinct. The cytoplasm was basophilic and finely granular with occasional cells containing a prominent, perinuclear clear zone. A few cells contained small numbers of clear vacuoles, and infrequently, cells had intracytoplasmic secretory vacuoles. Rarely, large cells contained other similar intact cells ( Figure 1C), and rare cells had a moderate amount of amorphous, magenta, glassy material within the cytoplasm. Nuclei had fine chromatin with multiple prominent nucleoli that varied markedly in size and shape. Multinucleated cells were found in moderate numbers, and there was marked variation of nuclear size within the same cell. Mitotic figures, including bizarre forms, were found in small numbers, and rarely, mitotic figures coexisted with intact nuclei within a multinucleated cell. There were a few small cellular aggregates with an acinarlike appearance. Cytoplasmic debris from ruptured cells and clear droplets were present. The background contained small numbers of nondegenerate neutrophils and vacuolated macrophages. The cytologic interpretation was malignant tumor with mild, mixed inflammation. With the exception of occasional acinar-like formations, the features were most typical of a tumor of mesenchymal origin. Differential diagnoses included liposarcoma, atypical amelanotic (balloon cell) melanoma, anaplastic sarcoma, and anaplastic carcinoma.

Cytologic features of clear cell adnexal carcinoma in 3 dogs

“…Lack of cells with definitive sebaceous differentiation and with immunoreactivity for Melan A and PNL‐2 helped exclude sebaceous carcinoma . In addition, all neoplasms reported here were negative for CD79a expression, which has been reported to stain canine sebocytes . Lack of epidermal contiguity helped exclude a diagnosis of clear cell basal carcinoma .…”

“…1,7 In addition, all neoplasms reported here were negative for CD79a expression, which has been reported to stain canine sebocytes. 7,8 Lack of epidermal contiguity helped exclude a diagnosis of clear cell basal carcinoma. 7,9 Negative immunoreactivity for calponin and a-smooth muscle actin, both myoepithelial markers, is consistent with previous reports.…”

Mammary Carcinoma with Sebaceous Differentiation in a Dog

“…In fact, sebaceous carcinomas arising from skin sites are uncommon and seldom show widespread metastasis in the dog. 2,4 The feature that distinguishes this case from a skin appendage tumor is the metaplastic transition of the intraductal papillary carcinoma from a small area of sebaceous differentiation to a large area of invasive sebaceous carcinoma with associated squamous differentiation.…”

CNS and lung metastasis of sebaceous epithelioma in a dog

“…Sebaceous gland tumours can be subclassified according to their histological appearance and clinical behaviour into five main types: nodular sebaceous hyperplasia, sebaceous adenoma, sebaceous ductal adenoma, sebaceous epithelioma and sebaceous adenocarcinoma 1,2,4,7 . Sebaceous hyperplasia was the most commonly diagnosed type (53.5%) in a series of 172 canine sebaceous gland tumours, 5 and is characterized histologically by circumscribed, nodular proliferations in the superficial dermis of mature sebaceous gland lobules around a central duct surrounded by a single layer of basal reserve cells 1 .…”

“…Sebaceous epitheliomas encompass 37.2% of sebaceous tumours and are irregular masses consisting predominantly of relatively uniform basal reserve cells that may have many mitotic figures interspersed with a smaller numbers of intermediate and mature sebaceous cells throughout the mass 5 . Sebaceous adenocarcinomas account for rare cases (1.7%) and are typically poorly circumscribed, irregular, multilobulated masses with irregular proliferations of pleomorphic and atypical polygonal cells with variable degrees of cytoplasmic lipidization and lacking significant numbers of well‐differentiated basal cells 1,2,7 …”