Primary Cylindroma of the Breast with Brisk Mitosis: A Case Report and Review of Literature.

Primary cylindroma of the breast is extremely rare. To the best of our knowledge, there have been only 18 tumors reported. All of them were benign and had no mitosis. However, the rarity of this entity made the correct diagnosis preoperatively very difficult. Here we present a unique cylindroma with focal brisk mitosis and largest diameter of 5cm in an 80-year woman, she was misdiagnosed as adenoid cystic carcinoma in biopsy and then underwent a radical breast resection. We reviewed the related literature and emphasized differential diagnosis. [ABSTRACT FROM AUTHOR]