Leptomeningeal gliomatosis as the initial presentation of gliomatosis cerebri.

Leptomeningeal gliomatosis is a known, yet uncommon, complication of malignant gliomas. In rare instances it can present with non-specific symptoms prior to the development of detectable intraparenchymal lesions, posing a diagnostic challenge. Gliomatosis cerebri is also a rare disease, characterized by extensive diffuse infiltration of neoplastic glial cells. For both entities, limited data exist to guide treatment and prognosis is poor. We describe the case of a patient who presented with symptoms of increased intracranial pressure and diffuse leptomeningeal enhancement in the brain and spinal cord on MRI. After a period of surveillance, intraparenchymal lesions developed in association with widespread diffuse infiltration. The diagnosis of gliomatosis cerebri with diffuse leptomeningeal gliomatosis was established in hindsight. Initial treatment consisted of six cycles of temozolomide chemotherapy. Following radiological progression, the patient received craniospinal radiotherapy. Four months later the patient's symptoms had resolved and MRI demonstrated near complete response of leptomeningeal enhancement and intraparenchymal lesions. Six months after radiotherapy, the patient remains clinically well without radiographic recurrence.