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Background
Adrenal glands can undergo tremendous changes throughout neonatal period and infancy. Adrenal pathologies in children depend on the child’s age. A plethora of conditions can affect the adrenal glands, ranging from benign to malignant, some of which are unique to children. Although neuroblastoma (NB) is the most common pediatric adrenal tumor, a wide spectrum of congenital, infectious, vascular, neoplasms and mass mimics may involve the pediatric adrenal gland.

Educational Goals / Teaching Points
Through this exhibit, we aim to describe the various adrenal gland pathologies that can affect the pediatric population. We will briefly review the anatomy and normal imaging appearance of the glands and describe the imaging appearance of a range of benign and malignant adrenal lesions encountered in children.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
The imaging modalities used in the diagnosis of adrenal lesions include Ultrasonography (US), Computed Tomography (CT), Magnetic Resonance Imaging (MRI), and various scintigraphy scans. Unlike in adults and older children, US is the imaging modality of choice in neonates. The normal appearance of neonatal adrenals on US is a pair of prominent glands with a large hypoechoic cortex and a central hyperechoic medulla. This is in contrast to individuals over 1 year of age, who share the appearance of an adult gland with a prominent medulla and indistinct corticomedullary junction. US also serves as an excellent tool for the serial imaging evaluation of neonates with adrenal haemorrhage, which is the most frequently encountered adrenal pathology in neonates. Identification of an adrenal lesion on US warrants further imaging either with CT or MRI, preferably MRI, owing to its lack of radiation. Certain adrenal lesions have characteristic imaging appearances such as congenital adrenal hyperplasia (CAH), which shows a cerebriform appearance of an enlarged gland with stippled echogenicity, and adrenal adenoma, which has a low CT attenuation (<10HU) and shows a characteristic drop in signal intensity on chemical shift imaging. In some cases, clinical and imaging correlation can help, such as pheochromocytoma showing a T2-hyperintense mass on MRI and avid postcontrast enhancement in a child presenting with hypertension and palpitations. In certain other cases, laboratory investigations and clinical features may aid in diagnosis, like in the case of an adrenocortical carcinoma with virilization or Cushing syndrome. NB and ganglioneuroblastoma can present with rapid-onset obesity with hypothalamic dysregulation, hypoventilation, and autonomic dysregulation (ROHHAD syndrome). Apart from these, a number of extraadrenal conditions can mimic adrenal pathologies such as extralobar sequestration and extramedullary hematopoiesis which are easily identifiable on imaging.

Conclusion
Pediatric adrenal lesions vary greatly from those in an adult. Imaging can help differentiate malignancies from some obviously benign pathologies with characteristic features, thus making multimodality imaging pivotal in the characterization of adrenal lesions.