Imaging of Paranasal Sinus Mucoceles

Introduction: Mucoceles are cystic masses developing after obstruction of the sinus ostium. The symptoms are not specific. Computed Tomography scan (CT scan) and Magnetic Resonance Imaging (MRI) confirm the diagnosis. Objectives: We herein review the radiologic characteristics of mucoceles in CT scan and MRI. Materials and Methods: We report a retrospective study of 43 patients diagnosed with paranasal sinuses mucoceles. CT scans were performed for all patients, but MRI was carried out only in selected cases. Results: Our study was constituted of 27 males and 16 females with a mean age of 47 years. The CT scan appearence of mucoceles were in all cases as a well circumscribed expansile sinus mass with an effect on the neighbor bone structure. This mass was hypodense in 26 cases, isodense in 14 cases and hyperdense in 3 patients. The paranasal sinuses most frequently affected in our series were the fronto-ethmoidal sinuses. The most affected bone eroded was the lamina papiracea. Intracranial extension was seen in four cases. CT scan allowed to predict the cause of mucoceles in some cases and to provide information about anatomic variants. MRI was realized for 15 patients in addition to the CT scan. It allowed to study the extension of mucoceles to the neighboring organs especially orbital and endocranial ones. Conclusion: The presentations of mucoceles on imaging are quite variable. CT scan provides precious information about the location, bone erosion and extension of the mucoceles. MRI is indicated in some cases especially in cases of orbital or cranial extension.