Cytology of micropapillary mucinous carcinoma: A case report of a clinically and genetically distinct breast carcinoma variant.

Micropapillary mucinous carcinoma (MPMC) is an uncommon histopathological variant of breast cancer accounting for approximately one-fifth of all mucinous breast carcinomas. In contrast to pure mucinous carcinoma, MPMC tends to affect younger women and is associated with decreased progression-free survival, higher nuclear grade, lymphovascular invasion, lymph node metastasis, and positive HER2 status. Typically MPMC histology shows micropapillary architecture with "hobnailing" of cells and reverse polarity. Very few publications document the cytomorphological findings of MPMC. We report a case of MPMC that was suspected in fine needle aspiration cytology (FNAC) and confirmed at histopathology.