Ultrasound Imaging in the Diagnosis of Benign and Suspicious Adrenal Lesions

Abstract

BackgroundThe purpose of this study was to define the ultrasound imaging characteristics of adrenal tumors and to assess the performance of ultrasound in differentiating benign ‘leave-alone’ lesions from suspicious lesions.Material/MethodsWe enrolled 882 patients in this study. The nature of each lesion was determined by histopathology. Ultrasound finding of each lesion was compared with its corresponding histopathologic result. The final study group consisted of 911 adrenal masses in 882 patients. All images were reviewed by 2 experienced investigators in a double blind manner.ResultsThere were 553 adenomas identified in the study, which constituted 60.70% of the lesions. There were 161 pheochromocytomas (17.67%), 49 myelolipomas (5.38%), 39 cysts (4.28%), 37 metastasis (4.06%), 35 ganglioneuromas (3.84%), 22 lymphomas (2.41%), and 15 cortical carcinomas (1.65%). The sensitivity, specificity, and accuracy of ultrasound-based diagnosis were 89%, 99%, and 93.9%, respectively. A positive predictive value of 90.9% and a negative predictive value of 94.2% were obtained in this study.ConclusionsThis large-sample study showed that ultrasound was a reliable method in differentiating benign ‘leave-alone’ lesions from suspicious lesions.

Ultrasonographic features of adrenal gland lesions in dogs can aid in diagnosis

“…A high prevalence (32%) of adrenal cortical hyperplasia was also noted. As reported in humans, the majority of histologically diagnosed adrenal lesions were benign, such as cortical hyperplasia (65.1% of cases in our series) rather than neoplastic [1]. Our results are in agreement with data reported by a previous study in dogs based on histological examination showing a prevalence of 19% of adrenal neoplasia and 41.5% cortical hyperplasia [16].…”

“…In agreement with previous studies [12] cortical adenomas were macroscopically characterized by a nodular pattern. In humans, they usually present as homogeneous hypoechogenic and solid focal or multifocal nodules with well-defined borders [1]. The only adenoma identified by ultrasound in our study appeared as heterogeneous multifocal nodules with several small areas of inner calcification producing acoustic shadowing.…”

“…Indeed, all 8 cases (4/17 cortical carcinoma and 4/10 pheochromocytoma) were diagnosed as vascular infiltration of malignant neoplastic cells, but it was not specific for the type of primary adrenal neoplasia [1, 12, 21]. In our sample, vascular invasion was a specific, but not sensitive ultrasonographic parameter.…”

“…In human medicine, the use of advanced imaging techniques (e.g., ultrasound, computed tomography, scintigraphy, and magnetic resonance imaging) has resulted in the increasing identification of incidental adrenal gland lesions [1]. Among the methods of diagnostic imaging, ultrasound is considered a relatively rapid, non-invasive, inexpensive and reliable modality to evaluate suspected adrenal masses [2].…”

“…While ultrasonography is an effective method for localizing adrenal lesions, standardized ultrasound criteria to distinguish benign from malignant lesions or functional cortisol-secreting from non-functional tumors are lacking [12]. In large-scale studies involving human patients, ultrasound morphological and dimensional criteria have proven reliable in differentiating adrenal lesions: tumor malignancy potential estimated on the basis of its dimensions alone showed that about 90% of malignant tumors were >40 mm in diameter [1, 14]. In the dog, only one study to date has compared the ultrasonographic appearance of adrenal lesions with their histopathological characteristics.…”