October 2016

I-N20 (NP)


Signalment (JPC#1718684):  Age and breed unspecified dog.

HISTORY:  Dog presented with a reddened plaque-like growth involving the skin of the scrotum.

HISTOPATHOLOGIC DESCRIPTION:  Haired skin, scrotum:  Expanding the dermis is an unencapsulated, well-demarcated, 4 x 8 mm mass composed of densely packed, randomly arranged streams and bundles of plump spindle cells that form well-differentiated, variably sized, blood filled, vascular channels lined by endothelium and surrounded by smooth muscle and collagen bundles.  The spindle cells have variably distinct borders, moderate amounts of finely fibrillar, pale eosinophilic cytoplasm, elongate nuclei with finely stippled chromatin, and a single magenta nucleolus.  Mitotic figures are not observed.  Blood vessels within the mass are lined by endothelium with rounded nuclei, and larger centrally oriented vessels are often filled with erythrocytes, abundant fibrin, and aggregates of neutrophils.  Multifocally, there are predominately perivascular aggregates of degenerative neutrophils.  The epidermis is mildly hyperplastic, pigmented, and contains moderate amounts of orthokeratotic hyperkeratosis with a loss of adjacent adnexal structures.  Occasionally lymphatics of the superficial dermis are ectatic and collagen bundles are separated by clear space (edema).

MORPHOLOGIC DIAGNOSIS:  Haired skin, scrotum (per contributor):  Vascular hamartoma, breed unspecified, canine.










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