F-18 fluorodeoxyglucose positron emission tomography “super scan” in a patient of metastatic primitive neuroectodermal tumor of the kidney

We report F-18 fluorodeoxyglucose (FDG) “positron emission tomography (PET) super scan” akin to “super scan” of conventional skeletal scintigraphy, in a rare case of primitive neuroectodermal tumor (PNET) of the kidney. A twelve year old male patient of metastatic PNET of the kidney was subjected to a “true” whole body F-18 FDG PET scan including lower limbs and skull region as per the institution protocol. The images revealed extensive hypermetabolic areas corresponding to the computed tomography described renal, hepatic, and pancreatic lesions along with intense and non-uniform uptake in the marrows of axial and appendicular skeletal system. Interestingly, low background tracer concentration was observed along with very low F-18 FDG uptake in the brain, skeletal muscles of limb, mediastinum, and bowel. In view of these findings, the scan can be interpreted as “PET super scan” due to its resemblance with the super scan of skeletal scintigraphy. A repeat F-18 FDG PET scan after chemotherapy revealed marked treatment response with disappearance of “super scan”-like pattern, reduction in number, size, metabolic activity of the lesions, and stimulated marrow sans the previously diseased portion. Though uncommon, the reporting physician should be aware of “PET super scan” and its implications as described in this case.