Razi Journal of Medical Sciences

    Introduction: Aneurysmal bone cyst(ABC) is a benign lesion with variable and expansile growth that can occur in any part of the skeletal, mainly in long bones and vertebra. ABC in paranasal sinuses is rare with only 7 previous cases having been describes in the ethmoid, sphenoid and frontal sinuses. Case Report: We present a case of ethmoidal sinus ABC in a 15-year-old female presenting nasal obstruction, epistaxis, proptosis and lateral displacement of left orbit. Conclusion: PNS-CT revealed an expansile mass centred over the left ethmoidal sinus extending to left orbit and anterior cranial fossa with destroying the fovea ethmoidalis. MRI revealed the presence of a large cystic expansile mass and presence of multiple fluid levels within. Complete en-bloc excision was performed by using left frontal craniotomy approach, followed by immediate reconstruction of the nasal vault by using a split calvarial bone graft in combination with left ethmoidectomy and partial maxillectomy using left lateral rhinotomy approach.