Ossifying fibroma (OF) is a rare benign fibro-osseous tumor, mainly located in the head and neck region. Most often, it affects the mandible but rare involvement of paranasal sinuses has been reported, associated with more locally aggressive behavior.

We report the case of an 8-year-old boy with OF of the middle turbinate, revealed by ethmoiditis. Total resection was performed on an endoscopic approach. The patient was free of clinical or radiological recurrence at 3 years’ follow-up. This was the youngest patient with OF of the middle turbinate so far reported in the international literature.

Presumptive diagnosis is established by clinical examination and CT scan (location, oval-shaped mass, heterogeneous tumor with a thin bony rim). Definitive diagnosis is founded on histological examination (psammomatous bodies, osteoblastic rim, trabecular bone). Treatment in paranasal sinus OF is surgical, preferentially on an endoscopic approach. Resection should be as complete as possible to minimize risk of recurrence, especially in sinonasal locations, known to be more aggressive. Ethmoiditis in an unusual age-range should suggest tumoral etiology.