An Unusual Cause of Superior Vena Cava Compression: Delayed Mediastinal Migration of Hyaluronic Acid Breast Fillers.

Injectable breast fillers are increasingly used as minimally invasive alternatives to implants. Delayed complications such as migration and lymphadenopathy are increasingly reported. Mediastinal lymphadenopathy due to hyaluronic acid (HA) filler migration is rare. A woman in her 50s presented with progressive facial puffiness and chest wall venous distension. Six months earlier, an evaluation at another center had revealed mediastinal lymphadenopathy causing superior vena cava (SVC) compression. Video-assisted thoracoscopic (VATS) biopsy revealed chronic inflammatory infiltrates. Further targeted history revealed prior bilateral breast augmentation using HA fillers. Repeat computed tomography demonstrated interval enlargement of the mediastinal lymphadenopathy with worsening SVC compression, together with radiological features suggestive of migration of filler material into the mediastinal nodes. Endobronchial ultrasound-guided transbronchial needle aspiration yielded polymorphous lymphocytes. Magnetic resonance imaging of the breast demonstrated multiple bilateral lesions with irregular capsules. Following corticosteroid therapy, the patient experienced marked improvement in clinical symptoms, with a reduction in the mediastinal lesion on follow-up imaging.