A cystic trichoepithelioma in a dog - A case report

Abstract

Trichoepithelioma is a benign, well demarcated subcutaneous tumor that originates from hair follicle matrix or inner root sheet. A 4 year-old female Golden Retriever was presented to Department of Veterinary Clinical Complex, Veterinary College, Hassan with a history of growing mass on the left lateral digit of right forelimb. On physical examination, the mass was found to be soft in consistency and radiography revealed soft tissue swelling at 5th digit involving all the 3 phalanges. The mass was surgically excised and representativetissue samples from the mass were collected and processed by routine paraffin embedding technique, sectioned at approximately five micron thickness and stained with routine Haematoxylin and Eosin method. Histo-pathological examination of the mass showed several cysts of variable size with trichogenetic differentiation. Cysts wall were lined by thickened basal lamina cells having palisade arrangement of cells near the periphery along with shadow cells in the cystic lumen. Trichoepithelioma is considered as significant because of its histological similarities to basal cell carcinoma, and although benign, there is a rare risk of malignant transformation. The present communication describes pathological findings in a case of cystic trichoepithelioma involvingthe let lateral digit of right forelimb in a female dog.