A patient with Alzheimer's disease complicated by elderly-onset Cushing's syndrome who had undergone surgical treatment for adrenocorticotropic hormone-independent macronodular adrenal hyperplasia.

Cushing's syndrome (CS) is a rare disorder, especially in older people. Loss of brain volume and neurocognitive impairment of varying degrees has been demonstrated in patients with CS. However, there is a large difference between the median age of presentation of CS and that of Alzheimer's disease. We herein report a case of a patient with Alzheimer's disease complicated by elderly-onset CS who had undergone surgical treatment for adrenal hyperplasia. Surgical correction of hypercortisolism seems to have slowed the progression of brain volume loss and cognitive dysfunction and improved psychiatric symptoms such as visual hallucination, restlessness, and psychomotor excitement. These improvements have remarkably reduced the burden on the patient's caregivers. The present case suggests that subclinical CS may be present, particularly in rapidly progressive dementia, and that surgical treatment of CS for neuropsychiatric symptoms is useful.