High-grade malignant transformation of a radiation-naïve nasopharyngeal angiofibroma

Background Nasopharyngeal angiofibromas are typically considered benign vascular neoplasms, with descriptions of high-grade sarcomatous change found only in lesions with prior radiotherapy. Methods and Results We describe the first reported case of high-grade malignant change in a nasopharyngeal angiofibroma naive to radiation. A 45-year-old man presented with left-sided nasal congestion and fullness and was found to have a left-sided nasopharyngeal mass with intracranial extension on CT scan. A biopsy of the mass revealed nasopharyngeal angiofibroma. The patient opted for MRI surveillance, which revealed interval growth 3 years later. Decompression surgery revealed only angiofibroma, but resection 9 months later demonstrated high-grade sarcoma and concomitant angiofibroma. The patient had residual disease which progressed through chemoradiation, and is now pursuing clinical trial enrollment. Conclusion Malignant transformation of nasopharyngeal angiofibroma is extremely rare. As highlighted by this report, high-grade undifferentiated lesions may arise in tumors without previous radiation.