Cytologic Findings of Breast Mucinous Carcinoma with Micropapillary Pattern: Report of A Case and Literature Review

Mucinous lesions of the breast represent a broad spectrum of entities, which may pose a diagnostic challenge on fine-needle aspiration cytology. Mucinous carcinomas are so bland cytologically that they may be misdiagnosed as benign lesions, especially in cellpoor samples with ample mucin [1]. Assessment of cytologic details in conjunction with the radiological and clinical findings leads to a more accurate diagnosis. In addition, micropapillary carcinoma of the breast is known for the high risk of lymphatic invasion and metastasis. Wai-Kuen Ng has suggested a new subtype of mucinous carcinoma, morphologically equivalent to a mucinous counterpart of micropapillary carcinoma, in a large review series [2]. A recent study by Ranade et al. [3] has described that pure mucinous breast carcinoma with a micropapillary pattern were more frequently associated with nodal disease [3]. Thus prompt axillary staging is recommended in these patients. Herein we present a case of mucinous carcinoma with micropapillary pattern, demonstrating the cytologic and histologic features that warrant special attention.