Atypical central nervous system lymphoma at the cranial base: report of four cases

Primary central nervous system lymphoma is a disease with increasing incidence. Atypical presentations are becoming more frequent. Three patients bearing cavernous sinus lesions presented initially with periorbital pain and diplopia. Tolosa-Hunt syndrome was the initial presumptive diagnosis for two patients, and meningioma was the diagnosis for the third patient. A fourth patient presented with left ear pain, and a mass in the left internal auditory canal was thought to represent an acoustic neuroma. For all four patients, an operative pathological diagnosis was obtained and was compatible with central nervous system lymphoma. All patients were treated with osmotic blood-brain barrier disruption with intra-arterial chemotherapy using a methotrexate-based regimen. All four cases included atypical presentations of lymphoma. These cases again illustrate that a correct diagnosis cannot be obtained based only on imaging and clinical findings.