Sinonasal inverted papilloma (IP) is a locally aggressive tumor found in the schneiderian membrane, lining the nasal cavity and paranasal sinuses.Patient concerns:
We report a case of a 63-year-old woman with undifferentiated carcinoma (UC) arising in an IP in the left maxillary sinus.Diagnoses:
The preoperative diagnosis was IP of the maxillary sinus.Interventions:
We performed endoscopic medial maxillectomy to remove the remnant mass in the left maxillary sinus.Outcomes:
Histological examination of the specimen revealed typical area of IP and sinonasal UC.Lessons:
Clinicians should consider sinonasal UC in the differential diagnosis of malignancy arising in the sinonasal IP.