Ultrasonographic Findings of 1385 Adrenal Masses: A Retrospective Study of 1319 Benign and 66 Malignant Masses

Objectives To evaluate the features of adrenal masses on ultrasonography and correlate the findings with the pathologic diagnoses to help distinguish benign from malignant adrenal lesions. Methods Ultrasonography was performed in 1363 patients with adrenal lesions. The following ultrasonographic parameters were recorded: size, shape, margin, echogenicity, echo texture, cystic necrosis, calcifications, and blood supply. The sensitivity and specificity of aggressive features for predicting malignancy were calculated. Results Of 1385 adrenal lesions, 66 (4.8%) were malignant: 33 malignant pheochromocytomas, 20 adrenal cortical carcinomas, 10 metastases, 2 leiomyosarcomas, and 1 primitive neuroectodermal tumor. The remaining 1319 (95.2%) lesions were benign: 832 adenomas, 182 pheochromocytomas, 153 nodular adrenal hyperplasia, 54 myelolipomas, 42 cysts, 23 ganglioneuromas, 10 schwannomas, 8 cortical tumor eosinophils, 4 teratomas, 4 tuberculosis, 4 primary pigmented nodular adrenocortical disease, and 3 Castleman disease. Most of the tumors were regular and hypoechoic. The malignant lesions were significantly larger than the benign lesions (mean ± SD, 6.3 ± 2.4 versus 4.6 ± 1.7 cm; P < .01). Significant differences between malignant and benign tumors were observed when comparing the shape, margins, echo texture and vascularization of the analyzed lesions ( P < .01). An irregular shape, poor definition of margins, heterogeneous echo texture, and vascularization indicated malignancy, with sensitivity and specificity of 45.5% and 97.0%, 34.8% and 99.2%, 92.4% and 97.3%, and 15.2% and 97.5%, respectively. Conclusions Ultrasonography could be an effective diagnostic supplementary tool for adrenal tumors. A large size, irregular shape, poorly defined margins, heterogeneous echo texture, and vascularization of adrenal lesions could be effective indicators of malignancy.