An Adrenocortical Carcinoma Evolving from A Small Adrenal Incidentaloma after Years of Latency

ABSTRACT Objective: Adrenal incidentalomas (AIs) are frequent clinical problems. Although most are benign and nonsecretory, the possibility of malignancy is a concern. We report here a case of adrenocortical carcinoma (ACC) evolving from a small AI, 3 years after initial detection. Methods: We report our case and review similar cases in the literature and current published guidelines for AIs. Results: A 47-year-old woman was incidentally found to have a small (13 mm maximum diameter), homogeneous, left adrenal lesion with low density on computed tomography (CT) performed for abdominal pain. Two years later, she underwent magnetic resonance imaging for back pain; the lesion then measured 20 × 15 × 17 mm and again appeared benign. Ten months later, she developed fatigue, night sweats, anorexia, and weight loss. On CT, the lesion now measured 100 × 90 × 130 mm and was heterogeneous; 18F-fluorodeoxyglucose positron emission tomography showed intense uptake. Tests for hormone hypersecretion were negative. She underwent left adrenalectomy, with symptom resolution. Histology showed ACC with high proliferative index (Ki67 = 40%). Conclusion: This is a rare case of ACC evolving from a small AI after years of latency. This case suggests the possibility of adenoma to carcinoma sequence in the pathogenesis of some ACCs and highlights the challenge in identifying such lesions without unnecessary and potentially harmful testings. Abbreviations: ACC adrenocortical carcinoma; AI adrenal incidentaloma; CT computed tomography; FDG fluorodeoxyglucose; HU Hounsfield unit; MRI magnetic resonance imaging; NR normal range; PET positron emission tomography