Respiratory epithelial adenomatoid hamartoma: A rare differential diagnosis of sinonasal mass.

Sino-nasal respiratory epithelial adenomatoid hamartomas (REAHs) are rare entity. They are benign tumors with excellent results after complete excision. We report a case of a 57-year-old male with a history of endoscopic surgery for right nasal polyps 20 years ago. The patient presented nasal obstruction that persisted for 10 years without anosmia nor epistaxis. Nasal endoscopy found a tissular mass filling the right nasal cavity extending to the nasopharynx. CT scan and MRI demonstrated soft tissue opacification of the right maxillary sinus and the homolateral anterior ethmoid cells with extension to the nasal cavity. The suspected diagnosis on imaging was an Inverted papilloma with a wide implantation base on the posterior part of the nasal septum. No endocranial or orbital extension was noted. The patient underwent endoscopic sinus surgery with complete extirpation of the tumor and a right ethmoidectomy. Histopathological assessment showed features consistent with REAH. No recurrence was noted at 1 year follow-up.