Adrenal black adenoma associated with preclinical Cushing's syndrome.

A black adenoma of the adrenal gland was laparoscopically removed from a 60-year-old man who presented with severe hypertension. Although laboratory findings were indicative of preclinical Cushing's syndrome, there were no clinical features characteristic of Cushing's syndrome. Microscopically, the tumor showed a proliferation of polygonal cells containing numerous brown-pigmented granules. Special staining studies revealed these granules to be lipofuscin. Electron microscopy also identified lipofuscin and lysosomes in these cells. The morphological appearance of the tumor and the adjacent atrophic non-tumorous adrenal cortex supports the assumption that the black adenoma caused preclinical Cushing's syndrome.