Cytological diagnosis of malignant melanoma in a dog

Abstract

A 9 years old male Rottweiler dog was presented to the Surgical unit of Madras Veterinary College Teaching Hospital with the history of mass located on its nail bed of the 4th digit of the forelimb. Fine needle aspiration procedure was performed from the mass and the smears were referred to the Centralised Clinical Laboratory, Madras Veterinary College, Chennai for cytological diagnosis. Cytological examination revealed population of pleomorphic cells which were round to elliptical in shape with centrally to eccentrically placed round to ovoid nuclei containing coarsely granular chromatin. The cytoplasm was abundant which were lightly bluish in colour containing numerous brownish to blackish melanin granules of variable sizes. In addition, numerous mitotic figures were also observed. Based on the cytological findings, the lump was diagnosed as malignant melanoma.