Abstract
Background : We report cytological and histological findings on breast cancer with cartilaginous and osseous metaplasia, focusing on cells from “transitional” tumor tissue.
Case : A 74-year-old-woman seen for a left-breast mass was confirm in mammography, ultrasonography and computed tomography (CT) to have a round tumor 4 cm in diameter below the left areola. Fine-needle aspiration cytology yielded a diagnosis of carcinoma necessitating surgical resection.
Cytological specimens showed many isolated variable-shaped malignant cells and a few cell clusters showing mild accumulation with loose cell connections positive for vimentin but negative for keratin in immunostaining. Histologically, adenocarcinomatous, cartilaginous, and osseous components occurred together with “transitional” tissue between components. Transitional tissue showed the same immunostaining reaction as cell clusters in cytological smears.
Conclusions : Cell clusters in cytological aspiration biopsy smears of the breast may be apt to be diagnosed as carcinoma. In this case, however, they were derived from transitional tissue. Cells in clusters not showing both severe accumulation and tight connections accompanied by many isolated malignant cells in breast smears must be considered as possible breast cancer with cartilaginous and osseous metaplasia.
