Confounding diagnosis of metastatic disease on FDG PET/CT due to cosmetic liquid silicone administration in breasts and gluteal regions with silicone migration to labia majora

Cosmetic liquid silicone injections can result in silicone-induced inflammation, chronic mastitis, migration to distant locations and lymphadenitis which can result in false positive nodal and distant metastases. This study demonstrates a patient with multifocal FDG-avid right breast malignancy with FDG-avid bilateral axillary, mediastinal and abdominopelvic lymph nodes. She also had extensive FDG-avid foci in the bilateral breasts and subcutaneous gluteal regions secondary to cosmetic silicone administration. There was migration of injected silicone via the inguinal ligaments into her bilateral labia majora. In patients with extensive silicone injections, contrast-enhanced MRI, FDG-PET/CT and FES-PET/CT may assist in follow up for malignancy recurrence as the standard mammogram, ultrasound and CT follow-up demonstrates limited detection of interval changes.