Preexisting adrenal masses in patients with adrenocortical carcinoma: clinical and radiological factors contributing to delayed diagnosis.

Adrenocortical carcinoma (ACC) is a rare endocrine malignancy that is usually large (>5 cm) at time of diagnosis. Delayed diagnosis significantly worsens survival. We describe adrenal gland morphology prior to ACC diagnosis and discern potential causes of delayed diagnosis. ACC patients seen at The University of Texas MD Anderson Cancer Center between 1998 and 2014 who had cross-sectional body imaging ≥3 months prior to their diagnosis. We conducted a detailed review of clinical and radiological features in these patients prior to ACC diagnosis. Of 439 patients with ACC, 25 had imaging preceding ACC diagnosis (5 with normal adrenal glands and 20 with preexisting masses). On the first available images, the median mass size was 2.8 cm (range 0-9) with median precontrast density of 36 Hounsfield units (range 17-43) and became 9 cm (range 1-18) at the time of ACC diagnosis. The median interval between first available image and ACC diagnosis was 20 months (range 3-89). In the 5 patients whose initial images showed normal adrenal glands, the time between the last normal scan and ACC diagnosis ranged from 5 to 36 months. The most common reason for delayed ACC diagnosis was the presumed benign status of the preexisting mass (n = 13, 65 %). Radiologically suspicious adrenal masses can precede ACC diagnosis and have variable growth patterns. ACC can also develop de novo within a few months in a radiologically documented normal adrenal gland. The presumed benignancy of preexisting masses based on size is the main reason for delayed ACC diagnosis.