Undifferentiated Pleomorphic Sarcoma Mimicking Breast Implant-Associated Anaplastic Large Cell Lymphoma.

Breast implant augmentation is a low-risk procedure with few life-threatening complications, most commonly rupture or leakage and contraction of the capsule. Breast implant-associated (BIA) malignancies are rare. Anaplastic large cell lymphoma (ALCL) is the most well-known neoplastic condition associated with breast augmentation. Carcinomas arising in association with implants have been reported but are rarer than ALCL. BIA-mesenchymal tumors are extremely rare and most are locally aggressive fibromatosis. To date, only seven cases of BIA sarcomas have been reported. Herein, we describe a case of silicone BIA-undifferentiated pleomorphic sarcoma (UPS) that was initially mistaken for ALCL because of a significant clinical and radiological overlap in presentation and imaging. Here, we present the morphological and molecular features of this rare neoplasm. We reviewed the existing literature related to BIA sarcomas to highlight the importance of considering this diagnosis in cases of recurrent ALCL-negative BIA effusions.