a rare case of cutaneous leiomyosarcoma in budgerigar (melopsittacus undulatus)

leiomyosarcoma in birds is relatively rare. this tumor as a muscle neoplasm was reported in captive and free ranging birds. smooth muscle cells may develop to the leiomyosracoma, but splenic smooth muscle trabeculae is most common site of the tumor growth. although budgerigars have an incidence of neoplastic diseases but smooth muscle tumors were rarely reported in this species. to the best of our knowledge, present case is the first report of cutaneous leiomyosarcoma in budgerigar. the bird was referred with a history of growing mass in subcutaneous tissue of abdomen. first bird was suspected to the egg impaction, but necropsy confirmed a firm, creamy structure that suspected to the tumor mass. no invasion was observed to the other organs. after excision of the mass, routine histopathologic evaluation and immunohisochemistry investogation were performed for desmin and smooth muscle actin (sma). histopathologic examination revealed spindle-shaped cell with cigar-shaped, round, or oval nuclei with cytologic criteria of malignancy including marked pleomorphism and high mitotic activity. these findings were consistent with immunohistochemistry profile of our case and thus confirmed as cutanous liomyosarcoma.