[Intrapituitary adenoma metastasis from lung cancer with progressive cranial nerve palsies: a case report and literature review].

We report a rare case of metastasis to a preexisting pituitary adenoma. An 80-year-old man with a history of pituitary adenoma and lung cancer presented with recent onset of bilateral visual impairment, oculomotor nerve palsies, and severe headache. A CT scan revealed a pituitary tumor expanding into the suprasellar region and infiltrating the bilateral cavernous sinuses. We performed transsphenoidal surgery and diagnosed the tumor as lung cancer metastasis to the pituitary adenoma. After the surgery, visual impairment and severe headache were resolved, and the patient underwent radiation therapy for the residual tumor. To the best of our knowledge, 20 cases of metastases to pituitary adenomas have been reported in the literature. Clinical features of metastasis to a pituitary adenoma are different from those of metastasis to normal pituitary gland. In the case of a pituitary lesion with acute aggravation, one should be aware of the possibility of metastasis to preexisting pituitary adenomas.