Primary leptomeningeal CD30 positive diffuse large B cell lymphoma disguise as meningioma in a young adult.

Primary leptomeningeal lymphoma (PLML) without brain parenchymal involvement or systemic disease is very rare, comprising of approximately 7% of all primary central nervous system lymphomas (PCNSL). PLML is a diagnosis of exclusion which should be confirmed on biopsy after ruling out metastasis from systemic lymphomas and dissemination from PCNSL. PLMLs usually present in the elderly with a short duration of illness. Herein, we describe a case of CD30 positive diffuse large B-cell PLML in a young 21-years-old male with review of literature.