Silicone Implant Incompatibility Syndrome: Mimicking Metastases on Fluoro-Deoxy-Glucose Positron Emission Tomography-Computed Tomography in a Treated Case of Carcinoma Breast.

Silicone implant incompatibility syndrome (SIIS) has been identified as a cause of systemic symptoms such as lymphadenopathy, myalgia, and dyspnea in patients with silicone implants. We present a case of 76-year-old female patient, treated for carcinoma left breast with mastectomy and silicone breast implant, chemotherapy, and radiotherapy 42 years ago. There was a history of implant rupture and removal 2 years ago. The patient presented with right axillary swelling and dyspnea. 18-fluorine fluoro-deoxy-glucose positron emission tomography/computed tomography (F-18 FDG PET-CT) showed mildly FDG-avid left anterior chest wall and right rectus abdominis deposits, multiple lymph nodes, and low-grade FDG-avid pneumonitis changes in both lungs. Biopsy from the chest wall and rectus abdominis deposit was negative for malignancy and revealed foamy histiocytes and foreign-body giant cell reaction, indicative of SIIS. SIIS is a mimic for metastases and should be considered as a differential diagnosis in FDG PET-CT interpretation in patients with silicone breast implant.