Sphenoid Sinus Mucocele Caused by a Completely Thrombosed Intracavernous Carotid Artery Aneurysm: An Unusual Association

Background Mucocele is an inflammatory disease caused by the retention of mucoid secretions within a paranasal sinus. Although rare, the presence of a vascular lesion inside the sphenoid sinus could determine ostium obstruction, thus causing mucocele development. Clinical Presentation An 84-year-old woman was referred to our institution due to a lesion abutting into the sphenoid sinus; she was complaining of constrictive frontal headache, progressive worsening of visual acuity in the left eye; later, sudden homolateral ptosis and diplopia occurred. The radiologic evidence was consistent with the diagnosis of thrombosed aneurysm of the right intracavernous carotid artery, surrounded by sphenoidal mucocele. The patient underwent an endoscopic endonasal transsphenoidal approach exclusively for sphenoid mucocele drainage. Conclusion Although rare, the presence of a vascular lesion inside the sphenoid sinus has to be considered among the possible diagnostic hypotheses of masses abutting in this cavity; the association with mucocele is even more rare and, to date, has not been described.