What the study found
The report describes a 13-year-old girl with a destructive right maxillary sinus mass that was ultimately confirmed as mesenchymal chondrosarcoma through detection of a HEY1::NCOA2 gene fusion. The authors present this as a rare pediatric case of maxillary mesenchymal chondrosarcoma with this fusion and sirolimus-based maintenance therapy.
Why the authors say this matters
The authors conclude that molecular diagnostics, especially RNA sequencing, are important for identifying mesenchymal chondrosarcoma and separating it from other high-grade pediatric sarcomas with similar appearance. They also suggest that finding the HEY1::NCOA2 fusion may support biologically targeted therapy.
What the researchers tested
This is a case report and literature review. The team evaluated imaging, histopathology, immunohistochemistry, comprehensive molecular analysis, and follow-up 18F-FDG PET/CT, and then used multimodal treatment including chemotherapy, radiotherapy, surgery, and maintenance sirolimus.
What worked and what didn't
Histopathology initially interpreted the tumor as fibrosarcoma, with diffuse vimentin positivity, a Ki-67 proliferation index of 35%–40%, and CD34 negativity. Molecular analysis confirmed a pathogenic HEY1::NCOA2 fusion and excluded ETV6::NTRK3 fusion; after VAC chemotherapy, radiotherapy, and debulking surgery, follow-up PET/CT showed a partial metabolic response, and sirolimus maintenance was started because disease persisted.
What to keep in mind
This is a single case report, so the findings are limited to one patient. The abstract does not provide longer-term outcomes, and it does not describe broader effectiveness of sirolimus-based maintenance therapy beyond this case.
Key points
- A 13-year-old girl had a destructive mass in the right maxillary sinus.
- The tumor was initially read as fibrosarcoma on histopathology.
- Comprehensive molecular analysis confirmed a HEY1::NCOA2 gene fusion and excluded ETV6::NTRK3 fusion.
- Treatment included VAC chemotherapy, radiotherapy, debulking surgery, and sirolimus maintenance.
- Follow-up 18F-FDG PET/CT showed a partial metabolic response.
Disclosure
- Research title:
- Pediatric maxillary mesenchymal chondrosarcoma was confirmed by HEY1::NCOA2 fusion
- Authors:
- Şule Çalışkan Kamış, Begül Yağcı, Ayşe Selcan Koç, Güliz Durak, Ali Yitik
- Publication date:
- 2026-03-05
- OpenAlex record:
- View
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