A Giant Mammary Hamartoma in a Young Breast Cancer Patient

Background Hamartomas of the breast are rare benign tumors. Pre- and also postoperative differentiation from other benign or even malignant tumors is challenging. Case Presentation A 36-year-old female presented with a giant tumor of the left breast. The patient had suffered from an early breast cancer of the contralateral right breast the year before, which was treated with breast-conserving therapy, radiation, and endocrine therapy ever since. The hamartoma was classified as BI-RADS 2 in mammography and BI-RADS 4 in ultrasound. On clinical examination, a tumor of nearly 15 cm in size led to an abstruse deformity of the breast and the nipple-areola complex. We found an indolent, grand bulging tumor with an elastic texture directly beneath the skin. A biopsy that had been performed before was compatible with the suspected hamartoma. Because of the remaining diagnostic uncertainties after contralateral breast cancer and the progressive malformation of the left breast, a tumor extirpation utilizing a reduction mammaplasty was performed without complications. Subsequent genetic analyses excluded a loss of PTEN in this patient. Conclusion We presented the rare case of a 36-year-old woman with a history of breast cancer and a 700-g breast hamartoma. The preoperative and even the postoperative specification of a hamartoma remains challenging, and associations with genetic alterations should be considered.