Abstract: Malignant tenosynovial giant cell tumor (MTGCT) is clinically rare and predominantly metastasizes to lymph nodes and lungs, with renal metastasis occurring less frequently. The authors report a case of MTGCT involving the right ilium with right kidney metastasis detected by ¹⁸F-fluorodeoxyglucose (FDG) PET/CT in an elderly female patient. The characteristics of this disease are analyzed from the aspects of clinical manifestations, pathology, imaging diagnosis and differential diagnosis, staging, and follow-up monitoring, respectively, aiming to improve the clinicians' ability to diagnose and treat this disease.