Basosquamous cell carcionoma: An usual high risk varient of basal cell carcinoma at perianal region of a cow

Basosquamous cell carcinoma, a squamous differentiated basal cell carcinoma in perianal region of a cow was reported. Basosquamous cell carcinoma is a rare malignant cutaneous tumour featuring both basal cell carcinoma and squamous cell carcinoma. A Holstein Friesian crossbred cow with a growth below the anus was reported. On physical examination, the growth was found in between anus and vulva. Grossly, the mass was irregular, firm, ulcerated, reddish grey in colour. Histologically, the mass had basaloid and squamoid compartments. Basaloid cells were pleomorphic extending deep in to the dermis forming cords and or nests. Centre of the nests show squamous differentiation and often with keratinocytes forming whorls. Transition zone was apparent. Based on the histopathomorphology, the tumour was diagnosed as basosquamous cell carcinoma. This report records a very rare incidence of perianal basosquamous cell carcinoma in a Holstein Friesian crossbred cow.