September 2016



Signalment (JPC # 1945587):  Age and breed unspecified dog

HISTORY:  Tissue from a fluctuant mass

HISTOPATHOLOGIC DESCRIPTION:  Haired skin:  Expanding the subcutis and elevating the dermis and adnexa is a well-circumscribed, unencapsulated, multi-cystic neoplasm composed of a single layer of polygonal to flattened cells lining multiple cystic structures up to 2mm in diameter, supported by a variably dense fibrous stroma.  Neoplastic cells have indistinct cell borders with moderate amounts of eosinophilic granular cytoplasm which often exhibits apical blebbing. Nuclei are round to oval, with finely stippled chromatin and up to 2 variably distinct nucleoli.  Mitotic figures are not observed. Multifocally within the dermis apocrine glands are ectatic with attenuated epithelium.

MORPHOLOGIC DIAGNOSIS:  Haired skin:  Apocrine gland adenoma, cystic (apocrine cystadenoma), breed unspecified, canine.

SLIDE B: (JPC# 2147438):  Age and breed unspecified, dog

HISTORY: Ulcerated mass from the foot

HISTOPATHOLOGIC DESCRIPTION:  Haired skin:  Effacing the dermis, elevating the overlying, multifocally ulcerated epidermis, and infiltrating the subcutis is an unencapsulated, poorly circumscribed neoplasm composed of polygonal cells arranged in varisized, haphazardly arranged tubules, with disorganized cells piling up to 3-4 layers and occasionally forming small papillary projections, often surrounded by loosely arranged reactive fibroblasts on a dense collagenous stroma (desmoplasia).  Neoplastic cells have indistinct cell borders and moderate amounts of eosinophilic granular cytoplasm with occasional apical blebbing. Nuclei are irregularly round with finely stippled chromatin and generally one indistinct nucleolus. Anisocytosis and anisokaryosis are moderate.  Mitotic figures average one per high power field.  Frequently, tubules are filled with an amorphous eosinophilic material (secretory product), sloughed epithelial cells, necrotic cellular debris and degenerate neutrophils.  Lymphatics throughout the deep dermis, subcutis and underlying musculature contain rafts and tubules of neoplastic cells.  There are scattered perivascular nodular aggregates of lymphocytes, plasma cells and fewer macrophages, and vessels occasionally contain aggregates of neutrophils.  The overlying epidermis is ulcerated with a serocellular crust composed of many viable and degenerate neutrophils and eosinophilic necrotic cellular debris.  The adjacent remaining epidermis is mildly hyperplastic with rete ridges, acanthosis, spongiosis and multifocal orthokeratotic and parakeratotic hyperkeratosis.

MORPHOLOGIC DIAGNOSIS: Haired skin, foot (per contributor):  Apocrine gland adenocarcinoma, breed unspecified, canine.


Apocrine cyst adenoma

Apocrine adenocarcinoma







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