Breast Pilomatrixoma in a 47-year-old Woman: Pathological and Radiological Diagnosis

Abstract

Background: Pilomatrixoma is a benign adnexal tumor with differentiation towards the matrix of the hair follicle and occurs mostly in the head, neck, and upper extremities of the child. Pilomatrixoma of the breast is considered a very rare tumor. Case presentation: Herein, we present a 47-year-old woman who was referred to the surgery ward for a palpable right breast mass. Imaging studies revealed a well-circumscribed lesion categorized as BIRADs3. Because clinically the lesion was large and had a stony hard consistency so patient underwent surgery and intraoperative consultation was negative and revealed a well-defined lesion composed of basaloid cells, multinucleated giant cells admixed with bone trabeculae, and nests of ghost cells. Immunohistochemical (IHC) studies were done and the cells were positive for AE1/AE3, Beta-catenin, and BCL2 and negative for Mart1 and CD117. Based on H&E and IHC studies, pilomatrixoma of the breast tissue was confirmed. Conclusion: Breast pilomatrixoma is a very rare benign neoplasm that could clinically mimic malignant neoplasm and should be considered in the differential diagnosis of breast masses