Immunocytodiagnosis of carcinocythemia in disseminated breast cancer.

A small number of large, malignant mononuclear cells were found in the blood of a patient with disseminated breast carcinoma. The detection of these scarce cells was facilitated by examining leukocyte concentrates. Cytochemical and immunochemical studies showed that these were epithelial cells, not hemopoietic cells. These findings, when correlated with the clinical features and the cytologic findings in blood and marrow, suggested that the malignant mononuclear cells in the blood were breast carcinoma cells. This study demonstrates the technical feasibility of accurately identifying cells in blood, which may stimulate interest in the study of cancer cells in the circulating blood. The method may also be applied to other cytologic specimens, such as fine needle aspirates, that contain only a few neoplastic cells.