第4脳室底部海綿状血管腫の摘出後，幻覚症とone and a half syndromeが見られた1例

Appearance of Hallucinations and One and a Half Syndrome after Resection of a Cavernous Angioma Located in the Fourth Ventricle Floor

I．はじめに

　今回われわれは，第四脳室底部の海綿状血管腫の術後，一過性に幻視を中心とした幻覚症とone and a half症候群を合併した1例を経験したので報告する．

A patient is described who simultaneously suffered from hallucinations and one-and-a-half syndrome fol-lowing surgical resection of a cavernous angioma lo-cated on the fourth ventricle floor.

A 30-year-old male was admitted having a 10 year history of progressive weakness and hypesthesia of the right extremities. Neurological examination revealed right hemiparesis and hemihypesthesia. A computerized tomography (CT) scan showed a well circumscribed mixed-density area at the left portion of the pontine tegmentum. Magnetic resonance imaging (MRI) incli-cated a mixed intensity core surrounded by hypointense regions on T2-weighted images. A red mulberry-like tumor was found, during surgical procedures, on the mid-and left-portion of the fourth ventricle floor. The tumor was totally resected and the histological diagno-sis was cavernous angioma. Visual hallucinations occur-red several times following surgery, being subsequently described as images of moving worms, a dump truck next to the bed, and a bed falling from the ceiling. The patient soon understood these objects were not real. He simultaneously exhibited left lateral gaze palsy associ-ated with left internuclear ophthalmoplegia i.e., one-and-a-half syndrome. Three months after surgery the visual hallucinations disappeared but the one-and-a-half syndrome was incompletely resolved.

According to the neurological signs and the MRI re-sults, the lesion site was considered to extend from the left lower pons to the midbrain. Previously reported op-erations of cavernous angioma of the fourth ventricle floor are also described.