Radiographic Characteristics of Adrenal Masses Preceding the Diagnosis of Adrenocortical Cancer.

Incidentally discovered adrenal masses are common and the clinical evaluation and surveillance aims to diagnose hormone excess and malignancy. Adrenocortical cancer (ACC) is a very rare malignancy. This study aims to define the imaging characteristics of adrenal tumors preceding the diagnosis of ACC. Patients with prior (>5 months) adrenal tumors (<6 cm) subsequently diagnosed with ACC were identified in a large registry at a tertiary referral center. Retrospective chart and image review for patient characteristics and initial, interval, and diagnostic imaging characteristics (size, homogeneity, borders, density, growth rate, etc.) was conducted. Twenty patients with a diagnosis of ACC and a prior adrenal tumor were identified among 422 patients with ACC. Of these, 17 patients were initially imaged with CT and 3 with MR. Only 2 of the 20 patients had initial imaging characteristics suggestive of a benign lesion. Of initial tumors, 25% were <2 cm in size. Surveillance led to the diagnosis of ACC within 24 months in 50% of patients. The growth pattern was variable with some lesions showing long-term stability (up to 8 years) in size. In conclusion, antecedent lesions in patients with a diagnosis of ACC are often indeterminate by imaging criteria and can be small. Surveillance over 2 years detected only 50% of ACCs. Current practice and guidelines are insufficient in diagnosing ACCs. Given the rarity of ACC, the increased risk and health care costs of additional evaluation may not be warranted.