Lovely adrenal glands

Clinical History

Healthy neonate was sent for checkup ultrasound.

Imaging Findings

Figure 1: A well-circumscribed, solid-appearing, inverted Y-shaped structure over the right kidney beneath the liver. Hypoechoic, peripheral cortex and the hyperechoic central medulla are well differentiated. There is no evidence of any cystic area, abnormal lobulation of focal abnormal area (Fig. 1a). The length of one limb is 15 mm and its thickness is 5 mm (Fig. 1b).
Figure 2a: A well circumscribed, solid appearing C or V-shaped structure over the left kidney encasing the upper pole cortex of the left kidney. Smooth margins and well-differentiated adrenal cortex and medulla are noted (Fig. 2a).
The length of one limb is 14 mm and its thickness is 5 mm (Fig. 2b).

These high resolution, typical ultrasound images are so lovely that radiologist's eyes enjoy seeing them.

Discussion

Adrenal glands are retroperitoneal organs located in the perirenal spaces. [1] The right adrenal gland is located posterior to the inferior vena cava and superomedial to right renal upper pole and the left one is located somewhat lower and more anterior relative to the left kidney. [2]
The configuration of adrenal glands is described as pyramidal, “V”-shaped, “Y”-shaped, [1] triangle, inverted “Y”-shaped [3] or as arrow head [4]. If the ipsilateral kidney has not developed, the adrenal gland can have a discoid appearance. [2]
The adrenal gland has a body and two limbs. [4] The limbs have a concave or straight border in older children, but may be convex with a bulbous tip early in life. [5]
The normal adrenal glands are relatively large and easy to see in the neonates, [6] but their size may decrease by fifty percent between 1 and 3 weeks of life [3]. They have a thick, uniform, hypoechoic, peripherally located cortex and a central, relatively thin and echogenic medulla. [7] With increasing age, the cortex becomes smaller and the medulla relatively larger. [7, 8]
Due to the relatively larger size and lower amount of retroperitoneal fat, ultrasound with high frequency probe can provide high-resolution images of normal neonatal adrenals. [1, 7] In a prospective study for adrenal gland visualization on real-time ultrasound over 92 neonates, the right gland was identified in 97% and the left in 83% of neonates. [7]
Various sonographic measurements are described to evaluate the adrenal size. [3] These measurements are used to support some clinically suspected pathologic processes like congenital adrenal hyperplasia.
The length of normal neonatal adrenal gland is between 0.9 and 3.6 cm (mean 1.5 to 1.7 cm) and its thickness ranges between 0.2 and 0.5 cm (mean 0.3 cm). [9]

Differential Diagnosis List

Final Diagnosis

Normal neonatal adrenal glands

URL:	https://www.eurorad.org/case/13304
DOI:	10.1594/EURORAD/CASE.13304
ISSN:	1563-4086