Mucinous Cystadenocarcinoma Coexisting with Invasive Ductal Carcinoma of the Breast: A Rare Case Report
ED17-ED19
Correspondence
Sandeep Mani,
63/7, Sri Krishna Nagar, Samichettipalayam, Jothipuram Post, Coimbatore-641047, Tamil Nadu, India.
E-mail: sandysandeep1607@gmail.com
Mucinous Cystadenocarcinoma (MCA) of the breast is a rare variant of primary breast cancer with an unknown aetiology and pathogenesis. It resembles MCA of the ovary and pancreas and accounts for about one to four percent of primary breast cancers. Less than 25 cases of primary breast MCA have been reported in the literature. These tumours belong to the family of mucin-producing carcinomas of the breast, which includes mucinous carcinoma, signet ring cell carcinoma, columnar cell mucinous carcinoma, and MCA. MCA presents as a well-circumscribed, solid, and cystic mass. It contains large cystic spaces filled with mucin and is lined by atypical columnar cells with intracytoplasmic mucin. In addition to routine examination of Haematoxylin and Eosin (H&E)-stained slides, immunohistochemistry is necessary for the accurate diagnosis of primary breast MCA and to differentiate it from pure mucinous carcinoma. These tumours typically do not express hormonal receptors, making them triple-negative. The authors report a case of a 49-year-old woman who presented with a lump in her left breast. Ultrasonography (USG) suggested the possibility of carcinoma or atypical fibroadenoma. Fine Needle Aspiration Cytology (FNAC) indicated features suggestive of carcinoma. A trucut biopsy revealed infiltrating ductal carcinoma with mucinous features. Subsequently, a left-modified radical mastectomy was performed, and the patient was diagnosed with mixed-type carcinoma, comprising an 80-85% MCA component and a 15-20% invasive ductal carcinoma component.