A large intrauterine mass was detected in a 49-year-old woman who presented with irregular vaginal bleeding and intermittent fever. 18 F-FDG PET/CT revealed a massive intrauterine tumor with heterogeneous and elevated 18 F-FDG uptake. Histopathological analysis of the hysterectomy specimen confirmed the diagnosis of an inflammatory myofibroblastic tumor of the uterus.