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

Abstract

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.