Thyroid carcinoma and secondary malignancy of the sinonasal tract.

The sinonasal tract in general and the maxillary antrum in particular are uncommon sites for primary or metastatic tumors. Recently a woman had severe left posterior epistaxis. Hemorrhagic thyroid tissue was in the left maxillary sinus. The patient also had roentgenographic and scintigraphic evidence suggestive of thyroid tissue in her lungs and spine. Sixteen years previously she had undergone a partial lobectomy for a thyroid tumor. Reports of metastatic thyroid carcinoma in the maxillary, ethmoid, or sphenoid sinuses apparently have not appeared previously in the literature. Thyroid carcinoma's ability to metastasize to a paranasal sinus is documented now, and the list of tumors of the sinonasal tract are to be included in the differential diagnosis of epistaxis increases.