Isolated Lymph Node Metastasis as Initial Presentation of Collecting Duct Carcinoma on 68Ga-Pentixafor PET/CT

Abstract A 64-year-old man was admitted to the hospital with low back pain. Enhanced CT imaging revealed an isolated retroperitoneal mass. Since primary retroperitoneal lymphoma could not be ruled out, the patient was enrolled in our clinical trial of 68 Ga-pentixafor PET/CT. The mass exhibited intense uptake of 68 Ga-pentixafor and was subsequently confirmed as lymph node metastasis originating from collecting duct carcinoma. Our case demonstrated that 68 Ga-pentixafor may lack specificity in distinguishing primary retroperitoneal lymphomas from other conditions.