A case of metastases to the paranasal sinus from rectal mucinous adenocarcinoma.

Metastases of malignancies to the sinonasal tract are rare. We report a case of metastases to the paranasal sinus from rectal adenocarcinoma. A 72-year-old woman, who had a history of therapy with rectal adenocarcinoma, came to our hospital for visual loss in her right eye. Computed tomography revealed soft tissue in the right paranasal sinus. She underwent endoscopic sinus surgery immediately and an easily bleeding tumor was found in the paranasal sinus. Magnetic resonance imaging showed a mass involving the posterior ethmoid, the sphenoid sinus, and the orbit. From the surgical specimen, we found that the tumor was a metastasis of a previously managed rectal mucinous adenocarcinoma. Metastatic carcinomas of the sinonasal tract have a high risk of heavy hemorrhage during endoscopic sinus surgery. When a patient with visual loss has a history of malignancy, a possible metastatic tumor should be considered before surgery.