Intracranial meningioma with ophthalmoplegia in a rhesus macaque (Macaca mulatta).

Meningioma is a tumor that develops in the meninges, including the dura mater, arachnoid mater, and pia mater, all of which surround the brain and spinal cord. In humans, meningioma is the most frequently encountered primary intracranial neoplasia and accounts for approximately 35% of all reported primary brain tumors in the United States.5,7 Clinical manifestations are dependent on the size and location of the tumor.3,23 To our knowledge, only 3 cases of naturally occurring meningioma in nonhuman primates have been reported; these cases affected 2 baboons and 1 collared brown lemur.17,19,21 The meningiomas of 2 of these previous cases were described only briefly as part of a disease survey of neoplasia in 100 free-ranging baboons and a captive prosimian population.17,21 The third report focused on the pathologic features of the meningioma described with no mention of the clinical signs in the baboon, although its location was similar to that of the case we describe here.19 In the current case report, we describe the clinical manifestations, postmortem examination, and diagnosis of an intracranial meningioma in a rhesus macaque (Macaca mulatta).