Cavernous venous malformation of the frontal sinus: CT and MRI imaging findings.

Cavernous venous malformations (CVMs) of the paranasal sinuses are rare benign vascular lesions that can mimic aggressive neoplasms. Here, we report a 24-year-old male presenting with progressive nasal obstruction, rhinorrhea, and visual impairment. Preoperative CT demonstrated an expansile, soft-tissue mass within the left frontal sinus, characterized by a delicate osseous shell, internal radial bony ridges, and a pedunculated attachment to the anterior sinus wall. Dynamic contrast-enhanced MRI revealed progressive centripetal enhancement with a characteristic "slow-filling" pattern. The lesion was successfully excised via an endoscopic approach. Histopathological analysis confirmed the diagnosis of CVM, demonstrating multiple irregular vascular spaces lined by flattened endothelial cells within the mucosal stroma. Postoperative outcomes were favorable without recurrence. CVM should be included in the differential diagnosis of unilateral frontal sinus masses when bony remodeling, internal radial ridges, and progressive centripetal enhancement are present. Combining CT and MRI findings is indispensable for distinguishing CVM from other sinonasal lesions and guiding minimally invasive endoscopic resection.