Cytologic presentation of primary leptomeningeal sarcomatosis.

The cytologic findings in the cerebrospinal fluid of a 25-year-old male who presented with a diffuse neurologic disease clinically diagnosed as meningoencephalitis are described. Primary leptomeningeal sarcomatosis was subsequently diagnosed at postmortem examination. The potential value of cerebrospinal fluid cytology as a primary diagnostic tool in this rare and unusual tumor is discussed.