Vol. 11, Special Issue 11 (2022)

Fibrosarcoma is a rare, highly malignant tumour of mesenchymal cell origin. A Labrador dog aged 11 years was presented with a history of anorexia and depression. On clinical examination a growth was detected at the base of the tail. The growth was surgically removed and submitted for diagnosis to Department of Veterinary Pathology, College of Veterinary Science, Assam Agricultural University, Khanapara. The growth was examined cytologically and histopathologically. Cytological examination revealed individually arranged or aggregates of spindle shaped neoplastic cells with basophilic nuclei. Histopathologically, the tumour mass was composed of spindle shaped fibrous connective tissue cells. Eosinophilic collagen fibers were running in all directions. There was increased nuclear cytoplasmic ratio. Based on cytological and histopathological observation the tumour was diagnosed as fibrosarcoma.