A Periadrenal Gland Ewing Sarcoma With Extensive Posttreatment Ganglioneuroblastoma-Like Morphology in an Adult Patient.
Xi Wang, William Laskin, Hao Wu
✦ AI-curated · Sources linked
Case in brief
A 33-year-old man presented with a retroperitoneal periadrenal mass, exhibiting features of Ewing sarcoma. Initial biopsy revealed small round cells with Homer-Wright rosettes and positive CD99 expression. Following neoadjuvant chemotherapy, resection showed a biphasic tumor with ganglioneuroblastoma-like morphology alongside a minor round cell sarcoma component. EWSR1 rearrangement was confirmed in both biopsy and resection specimens.
What made this case unusual
The case highlights posttreatment cytodifferentiation resembling ganglioneuroblastoma in an adult with Ewing sarcoma, a phenomenon rarely documented in this demographic.
Diagnostic / clinical pearl
Clinicians should be aware that Ewing sarcoma can undergo cytodifferentiation post-chemotherapy, potentially mimicking neuroblastoma, which may complicate diagnosis.
Why it matters
Understanding this morphological change is crucial for accurate diagnosis and management, particularly in adult patients where such presentations are uncommon.