Cytochemical demonstration of neuromelanin in black pigmented adrenal nodules.

Retrospective review of 363 consecutive autopsy reports in which adrenal examination was noted reveal 8 cases of pigmented adrenal nodules. Black pigmented adrenal nodules have been reported infrequently both as incidental autopsy findings and in association with Cushing's syndrome. The nature of the pigment in these lesions has been assumed to be lipofuscin. Gross and histologic study of seven cases and electron microscopic study of two cases suggest the presence of a neuromelanin component in the pigment, a previously unreported finding in the adrenal cortex. Review of the clinical records of the patients suggested no associations with specific underlying disorders. The prevalence the authors report (2.2%) is less than that of a previous prospective study.