Characteristic cytological features of metastatic breast cancer to the lungs

Abstract

The authors studied the cytologic characteristics of pulmonary metastasis from breast cancer using 42 resected cases. Two types of typical cell features have been documented, for the first time, herein;small cell type (SCT) and large cell type (LCT). SCT showed small cancer cells, with overlapping and a high nuclear-cytoplasmic ratio (N/C ratio), forming papillary or spherical clusters. The cells contained hyperchromatic nuclei showing fine granularity and were somewhat less than twice the size of neutrophilic leukocytes. These findings were observed mainly in papillotubular and solid-tubular breast carcinomas. In LCT cases, large atypical cells with high N/C ratios sometimes appeared in irregular-shaped or gland-forming clusters with loose cell-to-cell connections. These cells were approximately double, or more, the size of neutrophilic leukocytes, They contained coarse and hyperchromatic nuclei, occasionally showing a papillary process. These findings were observed mainly in solid-tubular and scirrhous breast carcinomas. According to these cytologic characteristics, especially those of cell clusters and nuclei, the diagnosis of pulmonary metastasis from breast cancer is possible based on cytology.