High (18)F-FDG uptake by the remaining adrenal gland four months after surgery and initiation of mitotane treatment in two patients with adrenocortical carcinoma.

Two men, one 42 and the other 35 years old were both subjected to adrenalectomy for adrenocortical carcinoma (ACC). Adjuvant treatment with mitotane [o,p΄-dichloro-diphenyl-dichloroethane, (o,p΄-DDD)], was initiated following surgery. Mitotane is the only agent available at present for treatment in ACC because of a late-onset specific adrenocortical cell toxicity. Both patients underwent a (18)F-FDG-PET/CT scan, which revealed 4 months after starting treatment with mitotane significantly high (18)F-FDG uptake in the contralateral adrenal gland. Both patients underwent magnetic resonance imaging, while one had a laparotomy, because of an abcess at the site of previous adrenalectomy. No metastasis or size increase of the remaining adrenal glands were found suggesting that their hypermetabolic state could be attributed to mitotane treatment. Beside its cytotoxic delayed-effect, mitotane has an early -onset effect on steroid metabolism. In conclusion, an abnormal high (18)F-FDG uptake was observed in the contralateral adrenal gland in both our adrenalectomized ACC patients, 4 months after starting mitotane treatment, probably related to mitotane's effect on steroid metabolism, not yet fully understood.