[A case of papillary thyroid carcinoma metastatic to the sphenoid sinus presenting with epistaxis].

Distant metastasis from differentiated thyroid carcinoma is rare and metastasis to the paranasal sinus is extremely rare. We report a case of differentiated papillary thyroid carcinoma (PTC) with metastases to the sphenoid sinus presenting with epistaxis. An 81-year-old undergoing partial lobectomy for differentiated PTC 9 years earlier presented with intermittent epistaxis. Imaging showed a mass filling the sphenoid sinus and extending to the intracranial cavity. Histopathological diagnosis using endoscopic biopsy indicated a metastatic PTC tumor. Compared to the primary site, the metastatic tumor was poorly differentiated thyroid carcinoma. Despite external beam radiation therapy, her general condition worsened and she was moved to a hospice.