Dorsal brain stem lipomas: case report.

Intracranial lipomas are uncommon and rarely symptomatic lesions accounting for 0.06 to 0.46% of intracranial lesions. The management of symptomatic dorsal brain stem lipomas was once limited to cerebrospinal fluid diversion, but with recent advances in microsurgery, they now may be directly treated. We report three patients with dorsal brain stem lipomas, two of which involved the quadrigeminal cistern and one of which was in the cisterna magna region. Antenatal documentation by ultrasound examination in one patient represents the first reported in utero diagnosis of quadrigeminal cistern lipoma. Computed tomographic and magnetic resonance imaging scans were diagnostic. The surgical experience in two symptomatic patients is discussed. Microsurgical decompression was performed in each without neurological deficit, and clinical symptoms postoperatively subsided. No patient required a permanent cerebrospinal fluid shunt. The management of symptomatic dorsal brain stem lipomas is discussed, and an algorithm is proposed.