We report a rare case of nonapoplectic pituitary adenoma that did not invade the cavernous
sinus and was associated with isolated oculomotor nerve palsy. A 61-year-old male
was admitted to our hospital due to diplopia that had gradually worsened from 6 months
to presentation. He was diagnosed with right oculomotor nerve palsy, and brain magnetic
resonance imaging (MRI) showed a mass lesion within the sella. The tumor was homogeneously
enhanced on contrast-enhanced MRI. However, no findings suggestive of pituitary apoplexy
were found. Brain computed tomography revealed the tumor to have eroded the right
side of the posterior clinoid process by gradual expansion. Endoscopic transsphenoidal
surgery was used for complete resection of the tumor. Intraoperative findings showed
that the tumor did not invade the cavernous sinus. The histological diagnosis was
pituitary adenoma, and symptom improvement was observed from the early postoperative
stage onward. Surgical treatment is essential because oculomotor nerve palsy caused
by the enlargement of pituitary adenoma is not expected to resolve if treated conservatively,
unlike that caused by pituitary apoplexy.
Key-words:
Isolated oculomotor nerve palsy - microendoscopic transsphenoidal surgery - nonapoplexy
pituitary adenoma
