Carcinoma arising from fibroadenoma; presentation and management; a case series

Introduction: Although fibroadenomas is benign lesions, malignancy can occur in extremely rare cases; The aim of the current study is to report a case series of rare combinations of two breast tumors (carcinoma in situ within fibroadenoma). Methods: This is a retrospective case series study. The cases were managed in a single private center. They were evaluated and treated during the four years (January 2018-May 2022). It included all patients who had a fibroadenoma with malignant changes. Data, including the patient’s age, gender, marital status, past medical history, family history, ultrasound findings, mammography, fine needle aspiration (if available), and histopathological examination, were obtained from the center's database system. Results: There were a total of nine cases. The mean age was 41 years, with a range of 31-51 years. Eight (88.9%) of them were housewives, and just one (11.1%) was a teacher. only one (11.1%) of them was a smoker, and one (11.1%) had a family history of breast cancer. Breast mass was the most common presentation in eight (88.9%)) cases. In seven (77.8%) cases, a lumpectomy with wide local excision was performed, and in two (22.2%) cases, a mastectomy with axillary lymph node dissection was conducted. Six (66.7%) of them had ductal carcinoma in situ in fibroadenoma, whereas the other three (33.3%) had lobular carcinoma in situ in fibroadenoma. Conclusion: Although fibroadenomas are the most common benign breast mass, it is rarely associated with malignant transformation.