Metastatic breast carcinoma in cerebrospinal fluid. A cytomorphometric study.

: A study was undertaken to quantitate the cellular characteristics of metastatic breast carcinoma in cerebrospinal fluid (CSF). Millipore filters of CSF from 15 patients with metastatic breast carcinoma were reviewed; 50 cells per case were evaluated when available. All cells in all cases shed singly or in loose clusters; tight balls or morulae were absent. All cells had regular, round-to-oval nuclei with finely granular chromatin. The majority of cells in all cases had single or multiple round nucleoli, granular cytoplasm with distinct borders and a mean nuclear-cytoplasmic ratio of close to 0.70. Cellular background, number of tumor cells per case, number and placement of nuclei and nuclear and cytoplasmic diameter varied both within and among the cases. There was significant variation in nuclear and cytoplasmic diameters both within and among the cases of infiltrating ductal carcinoma. Thus, the uniform appearance of the cells was due to consistent cytologic features, not to similarity in cell size. The cytologic profile of metastatic breast carcinoma is sufficiently characteristic to distinguish this tumor from other benign and malignant lesions that shed in the CSF.