The diagnostic challenge of tumors manifested initially by the shedding of cells into cerebrospinal fluid.

Patients in whom the first indication of a neoplasm is the shedding of its cells into cerebrospinal fluid (CSF) present a challenging problem in differential diagnosis. The purposes of this study were to review the frequency and differential cytopathologic diagnosis of this event and to compare the distribution of neoplasms in these presentations with the overall distribution of CSF malignancy. From 1971 to 1980, 12,026 CSF specimens were examined at Duke University Medical Center, and malignant cells were seen in 318 specimens from 232 patients. No follow-up was available for seven patients, and review of hospital records disclosed five cases of false-positive diagnoses. In 25 of the remaining 220 patients, cytologic examination of CSF provided the first documentation of a neoplasm. The distribution of the 25 initial CSF presentations was as follows: 2 of 108 leukemia/lymphoma patients, 8 of 44 lung carcinoma patients, 1 of 12 melanoma patients, 0 of 18 breast carcinoma patients, 0 of 14 patients with miscellaneous primaries, 2 of 3 patients with adenocarcinoma of the stomach, 5 of 7 patients with unknown primary tumors and 7 of 14 patients with primary brain tumors.