Pseudotumor associated with CNS lymphoma.

A 42-year-old immune-competent woman with orbital pseudotumor and presumed intracranial extension into the temporal lobe responded well clinically and radiologically to high-doses of corticosteroids. Five months later, she developed worsening headaches and recurrence of the temporal lobe lesion. Biopsy revealed a central nervous system (CNS) lymphoma with severe reactive gliosis abutting an area of subarachnoid lymphocytic infiltrate.