Mucocele-like tumor of the breast associated with ductal carcinoma in situand mucinous carcinoma : A case report

Mucocele-like tumor (MLT) of the breast is a rare neoplasm. Although this l esion was considered benign when first described, the concept of a patholog ic continuum with mucinous carcinoma was evident in subsequent reports. Onl y a few cases of MLT have been reported in Korea. We describe a case of MLT associated with ductal carcinoma in situ and mucinous carcinoma in a 34-yr -old female. Histological examination showed multiple mucus-filled cysts of varying size. Extravasated mucin was present in the surrounding stroma. Th e lining of the cysts in most areas were of flat or cuboidal epithelium and devoid of cellular atypia. The lining epithelium showed proliferative chan ge ranging from atypical ductal hyperplasia to ductal carcinoma in situ, mi cropapillary type. A microscopic focus of mucinous carcinoma within MLT was also noted. None of the lesions exhibited epithelial reactivity for p53 pr otein. The patient is alive and well without evidence of disease 54 months after initial treatment. This case supports the concept that MLT encompasse s a spectrum of pathologic lesions including benign tumor, atypical ductal hyperplasia, ductal carcinoma in situ, and mucinous carcinoma.