Diagnosis of lymphomatous leptomeningitis by cerebrospinal fluid lymphocyte cell surface markers.

We present a patient with metastatic lymphomatous leptomeningitis in whom the diagnosis was made on the basis of cerebrospinal fluid lymphocyte surface markers and later confirmed by cerebrospinal fluid cytology. The diagnosis of metastatic leptomeningitis can be elusive, and the differential includes a wide variety of infectious and noninfectious processes. We propose that lymphocyte surface marker studies can be a useful technique in expediting the evaluation of certain patients with lymphoma who have evidence of central nervous sytem involvement.