2026 年 13 巻 p. 385-388
Intracranial dermoid cysts are rare congenital lesions of ectodermal origin. Those arising in the Sylvian fissure are particularly rare, and rupture in this location has only infrequently been reported. A 54-year-old woman presented with a persistent headache after minor head trauma. Magnetic resonance imaging demonstrated a well-circumscribed 30-mm lesion in the left Sylvian fissure with heterogeneous hyperintensity on T1-weighted images. Multiple disseminated hyperintense droplets within the basal cisterns suggested cyst rupture. The patient underwent microsurgical resection via a trans-Sylvian approach. Intraoperatively, the cyst wall was partially deficient and adherent to the surrounding vessels. Owing to dense calcification of the wall and firm adhesion to adjacent neurovascular structures, the capsule was left in place, and the cyst contents were evacuated and curetted, followed by thorough irrigation. Histopathological examination confirmed a dermoid cyst. The postoperative course was uneventful, and no recurrence has been observed during 9 months of follow-up. Ruptured dermoid cysts in the Sylvian fissure are exceedingly rare. Recognition of disseminated lipid droplets is crucial for diagnosis, and safe resection with preservation of critical neurovascular structures is essential for favorable outcomes.
