Ocular amelanotic melanoma in goat - A case report

A four-year-old Jamunapari female goat was brought to veterinary dispensary, Radhanpur, Gujarat, India for left occular ulcerated growth. On clinical examination, the entire left eye globe and periocular tissues were effaced and expanded by ulcerated, necro-haemorrhagic growth along with intra-lesional maggots. Enucleation of the eye globe along with periocular tissue was performed and growth was fixed in 10% neutral buffered formalin and submitted for histopathology. Microscopically, unencapsulated, ulcerated, necro-haemorrhagic growth effaced the entire ocular tissue was noticed. In the centre of the mass, neoplastic cells showed biphasic pattern. In one part of the lesion, spindle shaped neoplastic cells arranged in short interlacing bundles, while in other part, polygonal neoplastic cells showed solid sheet like arrangement. In both the patterns, neoplastic cells had variable amount of eosinophilic cytoplasm, indistinct cell borders, large, round to oval or elongated, vesiculated nucleus with prominent nucleoli. Nucleus showed moderate pleomorphism. Mitotic figure were on average five per ten high power fields. On the periphery, widespread ulcers and necrosis, acanthosis, congestion, haemorrhages, few microfibrin thrombi and multiple bacterial colonies were noted. On immunohistochemistry, neoplastic cells showed strong cytoplasmic immunoreactivity with vimentin and PNL2 and non-reactive for cytokeratin, desmin, smooth muscle actin, and von willebrand factor. On the basis of gross, microscopic and immunohistochemical examination, neoplasm was diagnosed as ocular amelanotic malignant melanoma.