[Cerebellopontine angle lipoma with vascular anomaly: a case report]

A case was reported of cerebellopontine angle lipoma with vascular anomaly which was thought to be the remnant of fetal anastomosis of the posterior inferior cerebellar artery (PICA) and of the anterior inferior cerebellar artery (AICA). A 42 year-old man had been suffering from intermittent dizziness for a year. Worsening of dizziness after mild head trauma led him to visit a doctor who pointed out a cerebellopontine angle lesion. On admission to our hospital, neurological examination revealed no deficit. Computerized tomography (CT) scanning showed a low density mass in the right cerebellopontine angle, which was 1.5cm in diameter and showed no enhancement with intravenous contrast material. The attenuation value on CT of this lesion was--101 Hounsfield units. MRI showed a homogeneous mass, which was markedly hyperintense on T1 weighted image and proton image, isointense with chemical shift artifact on T2 weighted image and markedly hypointense on short TI IR (STIR) image. Signal characteristics on MRI were consistent with those of lipoma. Interestingly, MRI demonstrated the cranial nerves and vessels penetrating small lesion. The vertebral angiograms revealed the anastomosis of PICA and AICA with segmentally hypoplastic vertebral artery on the right side and the dilatation of the right distal AICA. Through a right suboccipital approach a yellowish mass in the right cerebellopontine angle was resected partially (about 50%). Only partial resection was possible because of the bleeding from small arteries and the tight adhesion to cranial nerves and brain stem. Histological findings of the surgical specimen were consistent with those of a lipoma. Postoperative neurological examination showed no neurological deficit.(ABSTRACT TRUNCATED AT 250 WORDS)