Fine-needle aspiration cytology evaluation of metaplastic breast carcinoma showing histological diversity

—A case report—

Abstract

Background : Metaplastic breast carcinoma is rare. We present a case of histologically diverse metaplastic breast carcinoma diagnosed by fine-needle aspiration cytology.

Case : A woman in her 70s was incidentally detected to have a mass in the C-portion of her left breast during a medical checkup. Fine-needle aspiration cytology revealed abundant cell clusters, including atypical polygonal cells with epithelial connections and atypical spindle cells. There appeared to be a transition between the polygonal and spindle cells. In addition, we observed atypical cell clusters surrounded by a hyaline-like substance. Based on the results of immunocytochemical analysis of the aspiration specimen, we diagnosed the patient as having metaplastic breast carcinoma. Histopathological examination showed a mixture of squamous cells and spindle cells, and the lesion was diagnosed as a mixed-type metaplastic breast carcinoma.

Conclusion : Immunocytochemical evaluation is useful for the diagnosis of mixed-type metaplastic breast carcinoma.