Septochoanal Polyp with Metaplastic Ossification Mimicking Sinonasal Tumor: A Case Report.

Choanal polyps are a form of nasal polyps that grow toward the choana with a single stalk. Septochoanal polyp is a rare entity that originates from the mucosa of the nasal septum with choanal extension. The most common site of its origin is mainly the superior aspect of the posterior portion of the nasal septum. However, metaplastic ossification is a rare event in nasal polyp and to the best of our knowledge, septochoanal polyp with metaplastic ossification has not been reported in the literature. Herein, we report a case of huge septochoanal polyp with metaplastic ossification obstructing both the nasal cavity and nasopharynx, which was successfully removed via transnasal endoscopic approach.