An one year old, female, Labrador dog was presented with a history of a big mass in right hindlimb. The mass was hard on clinical examination. Fine needle aspiration cytology (FNAC) revealed pleomorphic fibrocytes with prominent nucleoli. The mass was then surgically excised. Histopathology section showed fibrocytes arranged in varying patterns with numerous mitotic figures. Immunohistochemical study showed positive expression for vimentin and no expression for cytokeratin. Based on above findings the mass was confirmed as fibrosarcoma. | Histopathological and immunohistochemical diagnosis of canine fibrosarcoma
