Gastrointestinal leiomyosarcoma in an Egyptian fruit bat (Rousettus aegyptiacus)

A 10-year-old female Egyptian fruit bat (Rousettus aegyptiacus) was evaluated for weakness and lethargy. Despite clinical improvement after supportive therapy, the bat was found dead the following day. Gross necropsy identified a mass associated with the duodenal wall and right renal cortex. Microscopically, the duodenal and gastric tunica muscularis and serosa and the right renal cortex were effaced by interlacing bundles of neoplastic spindle cells that were diffusely and strongly positive for vimentin and alpha-smooth muscle actin. The neoplastic cells also had mild to moderate cytoplasmic labeling for laminin and S100 and were negative for c-kit and desmin. On the basis of cell morphology and the immunophenotype, this tumor was diagnosed as a gastrointestinal leiomyosarcoma.