Multicompartmental Paranasal Sinus Osteoma Complicated by Frontal Bone Hyperostosis, Intracranial Mucocele, and Inflammatory Pseudotumor

Abstract

Parasinusal osteoma complicated by intracranial and orbit extension, cranial vault hyperostosis, intracranial mucocele and inflammatory pseudotumor is exceptional. A 68-year-old man complaining a long history of progressive proptosis and recurrent episodes of keratoconjunctivitis of the left eye, with restriction in upward gaze, was observed. Contrast-enhanced magnetic resonance imaging revealed a frontal sinus lesion extending to the left anterior fossa and orbit, featuring intracranial cystic component and heterogeneous contrast-enhancement. Head computed tomography confirmed the double calcific-cystic nature of the lesion. A left supraorbital-pterional approach allowed the complete resection of mucocele and drilling of intracranial and orbital osteoma, including the intra-sinusal component. The frontal sinus was cranialized and a flap of pericranium, reinforced by Gelfoam sponge, was reflected on the anterior cranial base/orbital roof. The postoperative course was uneventful; MRI depicted resolution of the proptosis. The histologic examination was in favor of parasinusal osteoma associated to intracranial mucocele, frontal bone hyperostosis and inflammatory pseudotumor.