[A case of Cushing's syndrome caused by an adrenal black adenoma]

A black adenoma of the adrenal cortex was surgically removed from an 18-year-old female who had clinical and laboratory findings characteristic of Cushing's syndrome. The electron microscopic study revealed typical features of steroid-producing cells, including a prominent smooth and rough endoplasmic reticulum, and mitochondria. In addition, many of the adenoma cells contained numerous pigmented granules which were lipofuscin. Three months after the surgery, the hormone levels returned to the normal range. The Japanese literature of functional black adenoma is reviewed.