The cytopathology of cerebrospinal fluid. II. Metastatic cancer, meningeal carcinomatosis and primary central nervous system neoplasms.

The evaluation of cerebrospinal fluid (CSF) requires adaption of basic cytopathologic principles to the specific neoplasms that involve the central nervous system (CNS). In this review, general criteria for detecting malignant cells in CSF are presented. The incidence and cytologic characteristics of specific metastatic tumors that involve CSF are reviewed, and the incidence, pathogenesis and natural history of meningeal carcinomatosis are discussed. The role of cytopathology in the detection and management of primary CNS tumors is presented. Emphasis is placed on the cytologic characteristics of individual types of primary brain tumors and the application of fine needle aspiration biopsy to intracranial lesions.