Malignant Craniofacial Perivascular Epithelioid Cell Tumor: A Review of Literature With a Rare Presentation.

[BACKGROUND] Perivascular epithelioid cell tumors (PEComas) are rare mesenchymal neoplasms with smooth muscle and melanocytic differentiation, typically occurring in genitourinary or abdominopelvic sites. While multiple anatomic sites have been reported, craniofacial involvement is exceptionally rare.

[METHODS] We report the first documented case of a probable high-grade malignant PEComa of the sinonasal tract with anterior skull base and orbital extension. The patient was a 42-year-old woman with a germline RB1 mutation, prior radiotherapy for bilateral retinoblastoma as an infant, and a history of left-sided sinonasal leiomyosarcoma treated with surgical resection and anthracycline chemotherapy. She represented six years later with new contralateral epistaxis and a friable right-sided nasal mass. Upon endoscopy and imaging, a locally aggressive lesion was confirmed.

[RESULTS] Histopathology showed a highly proliferative tumor with immunohistochemistry positive for HMB45, melan-A, SMA, caldesmon, and TFE3, with absent desmin and MITF. The lesion was most in keeping with a malignant PEComa. The tumor was resected via a combined transcranial, transcaruncular, and endoscopic endonasal approach, achieving clear margins. This case shows unusually rapid progression, likely influenced by prior radiation and germline RB1 gene mutation. Our literature review identified 41 previously reported primary craniofacial PEComas, consisting of 51% sinonasal, 37% orbital, and 10% skull base. Nearly all cases were benign and treated with surgical resection.

[CONCLUSIONS] This report highlights a rare, malignant craniofacial PEComa with extensive invasion into the orbit and skull base, expanding the known clinical and molecular spectrum of these tumors.