Periocular Fillers–Related Complications: Imaging Features

• The surge in popularity of periocular fillers has heralded an increase in filler-related complications. • Short-term complications are usually mild and require no/minimal intervention. However, rare devastating vascular complications can occur. Long-term complications pose a diagnostic challenge and may require radiologic evaluation [1, 2]. • The chapter presents clinical-radiological manifestations of the commonly encountered periocular filler– related complications including intravascular embolism of the injected material, foreign body granuloma, chronic malar edema, and filler migration. • Acquaintance with the key imaging features of periocular filler–related complications is of paramount importance to avoid misdiagnosis and an unnecessary biopsy [3–5]. • Most commonly used fillers (i.e., collagen, HA, and CaHA) induce a physiologic inflammatory response, especially in the early postinjection period. The consequent mild enhancement/increased uptake on FDG PET–CT/MRI is attributed to vascularization and increased glycolysis in activated inflammatory cells and is not, by itself, indicative of infection. • Cellulitis appears as stranding and enhancement of the subcutaneous tissue adjacent to the injected filler (resembling inflammatory reactions). • Abscess formation appears as a rim-enhancing collection. On DWI abscess shows restricted diffusion whereas infected filler collections do not show restricted diffusion. • Foreign body granuloma may show a variable degree of enhancement on MRI. Definitive diagnosis requires histopathological evaluation.