Bronchioloalveolar carcinoma presenting with meningeal carcinomatosis. Cytologic diagnosis in cerebrospinal fluid.

The cytologic findings in a 35-year-old patient with bronchioloalveolar carcinoma who initially presented with central nervous system involvement are reported. Following the cytologic diagnosis of carcinomatous meningitis (metastatic adenocarcinoma), an open lung biopsy was performed, which confirmed the presence of a primary pulmonary neoplasm (bronchioloalveolar carcinoma). This case illustrates the importance of the cytologic diagnosis of a clinically unsuspected primary neoplasm. Further, together with three earlier reported cases, it indicates that, in young patients, tumor cells shedding into the cerebrospinal fluid can be the first indication of bronchioloalveolar carcinoma.