Isolated Lymphomatoid Granulomatosis of the Central Nervous System Mimicking Trigeminal Neuropathy, Bell's Palsy, and Glioblastoma in an Epstein-Barr-Negative Immunocompetent Host: A Case Report.

Lymphomatoid granulomatosis is an Epstein-Barr virus-associated lymphoproliferative B-cell neoplasm that typically involves multiple organ systems. This disease is exceedingly rare when confined to the central nervous system (CNS), usually presenting as a mass lesion or diffuse disease, with no existing standard of care. We present the case of a 67-year-old patient who had a unique and insidious course of isolated CNS lymphomatoid granulomatosis. The disease first presented with cranial neuropathies involving the trigeminal and facial nerves that were responsive to steroids both clinically and radiographically. Two years later, the disease manifested as a parietal mass mimicking high-grade glioma that caused homonymous hemianopsia. The patient underwent craniotomy for resection and was treated with rituximab after surgery. The patient has achieved progression-free survival more than three years after the surgery. Surgical debulking and post-procedural rituximab resulted in favorable survival in a case of isolated CNS lymphomatoid granulomatosis. An intracranial mass preceded by steroid-responsive cranial neuropathies should raise suspicion for lymphoproliferative disorder.