Cutaneous Pilomatrical Carcinosarcoma in a Dog.

Area of Science:

• Veterinary Pathology
• Dermatopathology
• Oncology

Background:

• Malignant pilomatricomas are uncommon skin neoplasms affecting both humans and animals.
• Pilomatrical carcinosarcoma, a rare subtype, has been previously described only in human medicine.

Observation:

• This article details a case of a nodular, partially alopecic neoplasm on a dog's hock.
• Microscopic examination revealed a tumor with both carcinomatous and sarcomatous components.
• The carcinomatous part showed cystic features and abrupt keratinization, while the sarcomatous part contained spindle cells and osteoid matrix.

Findings:

• Immunohistochemistry confirmed carcinomatous areas were positive for pan-cytokeratin and sarcomatous areas were positive for vimentin.
• E-cadherin expression was confined to the carcinomatous component.
• The tumor's unique morphology closely resembled human pilomatrical carcinosarcoma.

Implications:

• This case expands the known spectrum of pilomatrical carcinosarcoma to include veterinary patients.
• It suggests a shared etiology or pathogenesis for this rare tumor in dogs and humans.
• Further research may elucidate diagnostic and therapeutic strategies for canine pilomatrical carcinosarcoma.