Primary Neurolymphomatosis in the Cavernous Sinus and the Brainstem

Primary neurolymphomatosis is a rare condition that refers to lymphomas primarily presenting in cranial or peripheral nerves. Similar to primary central nervous system lymphoma (PCNSL), almost all cases of neurolymphomatosis are histologically classified as high-grade diffuse B cell lymphoma. Primary involvement of cranial nerves is extremely rare and manifests with signs and symptoms of mass effect. We present the case of a 67-year-old right-handed male who presented to hospital with progressive horizontal diplopia and left facial numbness in the V1 and V2 distributions. The patient subsequently developed ataxia, dizziness and nausea. An open biopsy was performed which confirmed the diagnosis of diffuse B cell lymphoma. The patient experienced rapid clinical improvement after the administration of chemotherapy and radiotherapy. We also review previous reports of primary neurolymphomatosis in the cavernous sinus. However, to our knowledge, this is the first case with concurrent involvement of the cerebellopontine angle.