Thymolipoma in a cat.

Thymolipomas are rare benign thymic neoplasms recognised in humans, composed of mature adipose tissue and thymic tissue. An 8-year-old male domestic shorthair cat presented with anorexia, lethargy and vomiting secondary to the development of a thoracic effusion and an anterior mediastinal tumoral mass with fatty appearance. Histologically, the mass consisted of adipose tissue containing numerous cords and nests of cortical and medullary thymic tissue. No signs of thymic epithelial or lymphoid neoplastic proliferation were detected. The findings in this case are remarkably similar to the macroscopic and histological features of thymolipoma in humans.