AbstractNowadays silicone is a widespread material for medical devices. In particular, it is commonly used for implants manufacturing, for that patients undergoing breast augmentation or breast reconstruction after mastectomy. However, the use of silicone implants is not free from risks. Ruptures of silicone breast implants are uncommon, in general post-traumatic or iatrogenic, and usually related to implant’s wall weakness of unknown origin but probably due to biochemical reactions that cause wall rupture. As a consequence of a rupture, silicone gel from damaged implants may have a continuity migration to the chest wall, axillae, and upper extremities, resulting in granulomatous inflammation or siliconoma, or a lymphatic migration to axillary lymph nodes. In this regard, silicone thoracic migration is extremely rare, and nowadays a leakage is unlikely to happen with more modern cohesive silicone gel implants. Nevertheless, procedures such as thoracic surgery and thoracotomies may be responsible for accidental breast implant rupture, capsular discontinuity, and eventually intrathoracic silicone migration, especially when dealing with older generations of breast implants. We report a rare case of a 75-year-old woman presenting with pleural silicone effusion, 18 years after a right breast reconstruction for breast cancer, followed by right upper lobe resection for a lung carcinoma. A combination of muscular flap and DTI pre-pectoral breast reconstruction with biological membrane (ADM) has been used for treatment. Literature was reviewed for cases of breast implants free silicone localization in the chest cavity, focusing on previous surgeries, anamnestic relevances, and surgical management.Level of Evidence: Level V, risk/prognostic study.