Primary leptomeningeal B-cell lymphoma in a 8-year-old child. A case of primary leptomeningeal B-cell lymphoma in an 8-year-old, previously healthy child is described. The child was found to have hypogammaglobulinemia, and the Epstein-Barr virus genome was identified in cultured tumor cells despite blood serology being negative for the virus. The patient was treated with cyclophosphamide, doxorubicin, vincristine, and dexamethasone, plus intrathecal methotrexate, and initially improved. Before the initiation of craniospinal radiation, the patient developed progressive disease, deteriorated, and died 9 months after the onset of symptoms. 