Purpose

To present the first reported case of melanotic PEComa with NONO:TFE3 fusion demonstrating simultaneous sinonasal, orbital, and intracranial involvement, and to discuss its clinical significance and multidisciplinary surgical management.

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Methods

A 36-year-old woman presented with a right sinonasal mass extending through the cribriform plate into the anterior cranial fossa and superomedial orbit. Initial management included bifrontal craniotomy for resection of the intracranial component. Following an almost two-year period of lost follow-up, reimaging demonstrated stable but persistent multi-compartment disease with extensive skull base invasion. The case was reviewed at a multidisciplinary tumor board and definitive resection was planned.

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Results

Histopathological and molecular analysis confirmed a melanotic PEComa harboring a NONO:TFE3 fusion, only the second reported melanotic PEComa with this fusion at a sinonasal site, and the first reported case with simultaneous sinonasal, orbital, and intracranial involvement. The patient underwent craniofacial resection via bifrontal craniotomy with radical orbital and skull base tumor resection, reconstruction of the orbit and anterior skull base using a radial forearm free flap, and tracheostomy.

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Conclusion

TFE3-rearranged PEComas are a molecularly distinct subset associated with aggressive behavior, with over half of reported cases demonstrating recurrence, metastatic spread, or disease-related death, as well as limited response to mTOR inhibitors, underscoring the importance of complete surgical resection. Notably, despite nearly two years without intervention, this case demonstrated relative disease stability without evidence of distant spread, possibly reflecting the variable natural history of this rare subtype. This case expands the spectrum of NONO:TFE3-fused melanotic PEComas and highlights the importance of molecular profiling and multidisciplinary planning in craniofacial PEComas.

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Additional Authors

First name	Last name	Base Hospital / Institution
Dr Kelsey A.	Roelofs	University of Alberta
Dr Hadi	Seikaly	University of Alberta
Dr Karolyn Hei Lun	Au	University of Alberta
Dr Frank Karel Hendrik	van Landeghem	University of Alberta

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