Visceral metastases of cutaneous fibrosarcoma in a Tigon - A case report

Abstract

A 20-year-old tigon (Tiger X Lioness) which was rescued from circus and housed at Nahargarh Rescue Centre, Jaipur, Rajasthan, showed a small growth on the ventral aspect of abdomen. The growth kept on increasing in size even after treatment with antibiotics. The case was diagnosed as cutaneous fibrosarcoma based on biopsy. The tumour was removed surgically and subjected to histopathological examination. The tumour mass showed intact epidermis but the dermis was found to be highly vas-cularised with extensive fibroblastic proliferation extending up to deep dermis without penetrating the hypodermis and muscles. The fibroblasts were fusiform to spindle-shaped with hyperchromatic nuclei and were arranged unevenly. Numerous mitotic figures were also observed. The Masson’s trichrome stained (MTS) duplicate skin sections showed proliferating fibroblasts with blue stained collagen. The condition of the animal was further deteriorated in the next two months and it died suddenly due to respiratory distress. On postmortem examination, the carcass was found to be emaciated with pale visible mucous membranes. Multiple whitish nodules were noticed throughout the parenchyma of both lungs. Similarly, a white peanut-sized nodule was present in the right renal cortex. The representative tissue samples were collected in 10 per cent (10 % NBF) neutral buffered formalin and processed conventionally for histopathological examination (HPE). Lungs and kidneys showed multiple neoplastic foci of numerous immature fibroblasts with elongated or oval hyperchromatic nuclei disrupting the parenchyma. The skin section from the primary site and lung tissues were showed intense positivity for proliferating cell nuclear antigen (PCNA) and vimentin in proliferating fibroblasts. This casereport describes cutaneous fibrosarcoma with visceral organs metastases in tigon.