Renal Ewing Sarcoma Mimicking Neuroblastoma: A Multitracer PET/Scintigraphic Imaging Pitfall.
Nivedita Kundu, Dikhra Khan, Sambit Sagar et al.
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Case in brief
A 6-year-old boy presented with a left suprarenal mass initially suspected to be neuroblastoma. An inconclusive biopsy led to further imaging, where I-131 mIBG scintigraphy showed no uptake, Ga-68 DOTANOC PET/CT indicated mild somatostatin receptor expression, and F-18 FDG PET/CT revealed intense hypermetabolism. A repeat biopsy confirmed renal Ewing sarcoma through EWSR1 gene rearrangement.
What made this case unusual
The case illustrates the diagnostic challenge posed by renal Ewing sarcoma, which can mimic neuroblastoma on imaging, particularly with discordant molecular imaging findings.
Diagnostic / clinical pearl
Clinicians should consider renal Ewing sarcoma in pediatric patients with mIBG-negative, FDG-avid lesions, especially when somatostatin receptor expression is low.
Why it matters
This case underscores the importance of multimodality nuclear imaging in accurately diagnosing pediatric renal masses, potentially preventing misdiagnosis and inappropriate management.