Abstract
It is not rare to encounter a difficulty in diagnosing mucinous carcinoma of the breast for its clinical resemblance to benign diseases. Among 459 cases of breast carcinoma, resected at First Department of Surgery, Yokohama City University Hospital, over the past 14 years between 1975 and 1988, 17 patients (3.7%) were diagnosed as mucinous carcinoma. Excluding two cases of double cancer, 15 cases were studied referring to clinical characteristics and compared with a group of 323 patients with infiltrating duct carcinoma. Preoperative diagnosis of malignancy in mucinous carcinomas by physical examination (inspection and palpation), echography and mammography could be made only in 35.7%, 15.4% and 30.8% of the cases respectively. It was more difficult in tumors smaller than 2 cm in diameter. A combination of these three diagnostic modalities did not increase the rate of correct diagnosis to be more than 50%. However, fine needle aspiration biopsy was found to be very effective in all cases. Compared with infiltrating duct carcinomas, mucinous carcinomas were smaller in size, and had less frequent lymph node metastasis, consequently better prognosis. One exception was the mixed type of mucinous carcinoma, whose prognosis was worse than that of the pure type demanding a careful follow-up.
