Glaucoma associated with a high number of mast cells in the uveal tract of an African lion cub.

An 8-week-old male lion cub (Panthera leo) was referred for evaluation of an enlarged and reddened left eye. Ocular examination revealed a buphthalmic left globe, with corneal edema, superficial neovascularization, moderate episcleral injection, a fixed dilated pupil, and an intraocular pressure of greater than 41.5 mm of Hg as measured by the Schiotz tonometer and a human conversion chart. A diagnosis of glaucoma was made. A silicone prosthesis was implanted after evisceration of the intraocular contents. Histologic examination of the eviscerated uveal tissue revealed numerous congested and dilated vessels of various sizes. Neutrophils were marginated along the vascular endothelium, and the uveal stroma was infiltrated by a few lymphocytes and numbers (3 to 30/hpf) of widely disseminated, well-differentiated mast cells with abundant, well-granulated cytoplasm.