Metastasis of a myxoid leiomyosarcoma via the renal and hepatic portal circulation in a sarus crane ( Grus antigone)

A 12-year-old female sarus crane ( Grus antigone) developed a recurrent proliferative lesion in the subcutaneous tissue of the tarsometatarsus, which failed to respond to medical and surgical therapy. The crane was killed and microscopic examination of the tissues taken at necropsy revealed a myxomatous, poorly-differentiated sarcoma with metastasis to the liver and kidney. Immunohistochemical staining for muscle actin, smooth muscle myosin and vimentin were positive, indicating that the primary and metastatic tumours were leiomyosarcomas. Location of the metastatic lesions in only the portal venous system of the liver and veins of the kidney indicated that the route of metastasis was the portal circulation via the ischiatic vein, caudal mesenteric vein and both the renal-portal shunt and hepatic portal vein. This is the first report of metastatic subcutaneous Leiomyosarcoma in an avian species