This chapter addresses the imaging diagnosis of permanent synthetic fillers in the breasts and their migration to axillary lymph nodes. It details the use of magnetic resonance imaging (MRI) as the gold standard for evaluation, with a particular focus on silicone and hyaluronic acid fillers. Special attention is given to the MRI protocol and the interpretation of sequences, including T2 with fat suppression and silicone-only imaging. This chapter also discusses the diagnostic limitations of ultrasound and mammography in these patients and explains how filler-related changes can mask or mimic malignant lesions. Axillary lymph node involvement is described with Doppler ultrasound and its differentiation from neoplastic conditions.