外転神経単独麻痺で発症し腫瘍内出血を伴った非機能性下垂体腺腫の1例

A Case of a Hemorrhagic Non-functioning Pituitary Adenoma Presenting with Abducens Nerve Palsy

Ⅰ．はじめに

　外転神経麻痺を呈する原因として動脈瘤や血管障害，外傷，腫瘍など様々な要因が知られているが，下垂体腺腫による外転神経麻痺の報告は極めて少ない^{5,6,9,17-20,22,25)}．今回われわれは，腫瘍内出血による外転神経麻痺で発症し，経鼻的腫瘍摘出術にて症状の改善をみた非機能性下垂体腺腫の稀な1例を経験したので若干の文献的考察を加え報告する．

A pituitary adenoma presenting with isolated abducens nerve palsy is an extremely rare occurrence. The authors report a rare case of a hemorrhagic non-functioning pituitary adenoma presenting with isolated abducens nerve palsy. The etiology of isolated abducens nerve palsy by a pituitary tumor is discussed.

　A 34-year-old male presented with severe headache,vomiting,right-sided ophthalmic pain,and diplopia. On admission,he had right-sided isolated abducens nerve palsy. Magnetic resonance (MR) images demonstrated a less-enhancing intra-and suprasellar mass lesion with intratumoral hemorrhage and right-sided slight cavernous sinus invasion,that exhibited an iso-high mixed intensity on T1-weighted image and a low-high mixed intensity on T2. Cerebral angiogram revealed no abnormality. The pituitary hormone function was within normal range. The tumor was totally resected via the transnasal route. The histological diagnosis was a typical non-functioning pituitary adenoma with hemorrhage. The abducens nerve palsy was completely resolved 7 months after surgery.

　It was supposed that the isolated abducens nerve palsy was caused by the direct compression of abducens nerve in the cavernous sinus by the extension of a pituitary tumor and hematoma. Pituitary adenoma should be considered in the differential diagnosis of abducens nerve palsy. Early diagnosis and transsphenoidal surgery is recommended to improve the abducens nerve palsy.