Effectiveness of endoscopic transsphenoidal surgery for gonadotroph adenoma mimicking dementia: A case report.

There are few reports of pituitary adenomas (PA) mimicking dementia. Delay in disease diagnosis and treatment may result in poor clinical outcome. We experienced a rare case where endoscopic transsphenoidal surgery (eTSS) effectively treated a gonadotroph adenoma mimicking dementia and report on literature considerations. We report the case of a 72-year-old man with chief complaints of cognitive decline, bradykinesia, anorexia, dressing apraxia, and vigor decline over several months. He was admitted to our hospital for scrutiny in a disoriented state. Blood tests showed hyponatremia and thyroid hormone depression. Magnetic resonance imaging showed a pituitary tumor, and preoperative endocrine stress tests showed reduced reactivities of growth hormone, adrenocorticotropic hormone/cortisol, and luteinizing hormone/follicle-stimulating hormone. Symptomatic pituitary adenoma was suspected, and eTSS was performed. The permanent pathological diagnosis was of gonadotroph adenoma. Postoperatively, the hyponatremia, cognitive decline, movement retardation, loss of appetite, dressing apraxia, and limb edema markedly improved. The patient was discharged under hydrocortisone 15 mg/day administration without complications. The endocrine stress test performed 2 months postoperatively showed secondary hypoadrenocorticism, while the other endocrine functions had normalized. No recurrence had occurred by 30 months postoperatively; the medication of hydrocortisone was gradually discontinued and the patient at the time was still being followed as an outpatient with modified Rankin Scale score 0. Secondary hypothyroidism and secondary hypoadrenocorticism due to the pituitary tumor primarily caused the condition. It is important to consider PA in the differential diagnosis of dementia, and early diagnosis and treatment can contribute to a patient's good clinical outcome.