Late recurrence of operated adrenocortical carcinoma: atrial natriuretic factor before and after treatment with mitotane.

A 62-year-old man arrived at our hospital with recurrence of Cushing's syndrome 14 years after successful surgery for adrenocortical carcinoma. Investigations demonstrated recurrence of a large tumor above the right adrenal area; it was found to be inoperable. The patient was treated initially with a new glucocorticoid antagonist, RU 486, and later with the adrenolytic agent mitotane (o,p'DDD). The latter achieved hypoadrenocorticism and a substantial reduction of tumor size. During the initial period, worsening hyperadrenocorticism resulted in a rise of atrial natriuretic factor and an inhibition of renin activity, consistent with an increase of cortisol and plasma volume. Changes in opposite direction were observed after treatment with mitotane.