Sinonasal paraganglioma with long-delayed recurrence and metastases: genetic and imaging findings.

Context: Sinonasal paragangliomas have rarely been reported in the literature. They are often aggressive.
Patient: We report an original case of sinonasal paragangliomas with a tumor recurrence diagnosed 13 years after resection of the primary tumor. Somatostatin receptor scintigraphy and [18F]-fluorodeoxyglucose positron emission tomography/computed tomography were the most sensitive functional imaging techniques, and they ruled out distant metastases. Interestingly, [18F]-fluorodihydroxyphenylalanine positron emission tomography/computed tomography was negative, a feature that may be considered a sign of functional dedifferentiation. Screening for germline mutations of the SDHB, SDHC, SDHD, SDHAF2, VHL, MAX, and TMEM127 was negative.
Conclusion: The diagnosis of malignancy remains challenging at initial diagnosis, and patients should be followed during their entire lifetime.