Inverted teeth in the nasal cavity are a rare clinical entity. We report herein on a case with resection via the endoscopic endonasal approach. A mass in the left nasal cavity was incidentally found in a 1-year-old boy at the local otolaryngologist, and the infant visited our department, suspected as having a nasal tumor. Anterior rhinoscopy indicated a peduncular lesion with partial calcification 3 mm behind the cutaneomucous transition site of the left nasal cavity. CT imaging indicated a mass with soft tissue density in the left nasal vestibule. We speculated an ectopic tooth or a teratoma including tooth tissue. We subsequently endoscopically removed the tumor via the endonasal approach under general anesthesia. The post-operative finding was an inverted ectopic tooth in the nasal cavity. Early diagnosis and treatment are required to prevent concomitant nasal symptoms.
