Extraordinary Response to Mitotane Monotherapy in Advanced Aggressive Adrenocortical Carcinoma

Adrenocortical carcinoma (ACC) is an aggressive tumor; the 5-year overall survival rate for advanced disease is 14 mg/L, but sometimes partial and complete responses have been reached with lower levels. No single clinical or pathological factor has been extensively validated to predict the response to mitotane monotherapy. We describe the case of a 45-year-old patient with metastatic, rapidly growing, unresectable ACC who had a remarkable response to mitotane monotherapy. After 4 months, a 45% reduction of the primary tumor and regression of lung metastases were observed, despite plasmatic mitotane levels of 5 mg/L. Mitotane may represent an effective therapy in selected cases of advanced ACC and despite plasma levels <14 mg/L.