18F-fluorodeoxyglucose-positron emission tomography in the characterization of suspected rhabdoid renal tumor recurrence: A case report

Rhabdoid tumor is a rare, aggressive, and undifferentiated cancer, that can be localized in the central nervous system, in the thorax or in the kidney. 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) is a noninvasive technique in cancer patients' management. Its role in the diagnosis and staging of rhabdoid renal tumor is not known at all. We report the case of a child with suspected recurrence of rhabdoid renal tumor studied with FDG-PET/computed tomography. A 4-year-old male previously treated for a rhabdoid tumor of the left kidney, underwent PET scan to differentiate local recurrence from postsurgical fibrosis. FDG-PET study showed the presence of intense, multiple, and inhomogeneous tracer uptakes in the left renal fossa (ie, the site of suspected computed tomography recurrence), with the involvement of the adjacent abdominal wall. Further pathologic uptakes were evidenced in the para-aortic, celiac, mesenteric areas, and at the hepatic hilum. Therefore, PET scan allowed a complete disease staging, evidencing unexpected local and distant disease extension. Thus, FDG-PET study could be considered in the evaluation of patients with renal rhabdoid tumor, at least when disease recurrence is suspected.