LOW-GRADE ADENOSQUAMOUS CARCINOMA OF THE BREAST - A CASE-REPORT WITH CYTOLOGIC FINDINGS AND REVIEW OF THE LITERATURE

The cytological and histopathological features of a case of low-grade adenosquamous carcinoma of the breast in a 47-year-old Japanese female was studied. The fine needle aspiration biopsy specimen of this case revealed proliferating ductal cells and atypical squamous cells in the same cell clusters. The resected left breast mass had a relatively we ll-circumscribed hard mass measuring 1.6 cm at its greatest dimension. Histologic examination demonstrated the coexistence of atypical squam ous and ductal components in the same lesion, with transition between these two components. Desmoplastic stromal reaction was observed. The majority of ductal components had a two-layered composition, and scler osing adenosis-like lesions were also observed at the periphery of the tumor. Based on these cytologic and histological findings, this tumor was diagnosed as low-grade adenosquamous carcinoma of the breast. Thi s is the first report of the cytological findings of low-grade adenosq uamous carcinoma of the breast, and it is important for pathologists t o consider the possibility of low-grade adenosquamous carcinoma when t he cytological findings described above are present in an aspiration c ytology specimen of the breast.