[A case of a hemorrhagic non-functioning pituitary adenoma presenting with abducens nerve palsy].

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.