Non-Infectious, Necrotizing and Granulomatous Aortitis in a Female Gorilla.

A 41-year-old female captive gorilla with progressive weight loss and hydrothorax of unknown origin was euthanized and submitted for necropsy. The ascending aorta showed intimal aortic thickenings, consistent with so called 'tree bark' changes. Microscopic examination revealed a non-infectious, necrotizing and granulomatous aortitis with no evidence of systemic vasculitis or infectious disease elsewhere in the body. While rare, large vessel vasculitides should be considered as a differential diagnosis in gorillas presenting with progressive non-specific signs and vascular intimal changes.