An extensive intrathoracic mass in an Andean bear Tremarctos ornatus proved
to be a thymoma, a tumour of the thymus. In addition a second tumour, a le
iomyoma (smooth muscle neoplasm) of the stomach, was diagnosed. The occurre
nce of two tumours in a threatened species is unusual and may be relevant t
o the conservation and management of the Andean bear.