Osteoblastoma of the maxillary sinus in a child presenting with exophthalmos

Benign osteoblastoma is a rare fibrous bone tumour observed in children. Very few cases involving the paranasal sinuses have been reported.

A 10-year-old child presented with a 1-month history of right exophthalmos. Clinical and radiological assessment demonstrated a heterogeneous tumour with bone components occupying all of the maxillary sinus. Initial histology was in favour of fibrous dysplasia. Surgery was performed via a combined approach. After review of the histology slides, the final diagnosis was that of osteoblastoma. In view of the procedure performed and after consultation, no complementary treatment was proposed. A recurrence was observed 8months later. Right maxillectomy associated with total ethmoidectomy via a combined approach was performed to ensure complete resection of the tumour. A favourable course without recurrence was observed with a follow-up of 5 years.

Osteoblastoma of the maxillary sinus is rare. CT assessment must be as precise as possible to avoid confusion with another tumour. The diagnosis can only be confirmed by histological examination. This case report is completed by a review of the literature with description of the main differential diagnoses.