Paediatric Radiology

Case  12 :  

A 19-day-old male child with history of birth asphyxia (Apgar 3 at birth) comes to the USG Dept, with a palpable lump in the right renal fossa, and hypertension.

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Fig 1

Fig 2 Fig 3 (after 2 weeks)
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Imaging Findings
USG reveals a cystic lesion in the upper pole of the right kidney, measuring 6 x 3 cm. The right kidney is seen clearly separate from this lesion. This cyst displays internal echoes within suggestive of hemorrhage. Progressive scan revealed thickening and calcification of the wall (Fig 3), with septations within. Intra-operative findings revealed right adrenal hemorrhage with secondary infection (pus with hemorrhagic fluid was seen on cut section).

In adrenal hemorrhage, differentiation from neonatal neuroblastoma is important and a follow up scan may demonstrate the mass reducing in size and eventually resolving, confirming the diagnosis of adrenal hemorrhage. In this case, the size remained the same and though there were changes noted (wall calcification), in view of the hypertension, and palpable lump, there remained a strong suspicion of cystic neuroblastoma.

US is the modality of choice for initial and follow-up evaluation of a flank mass in a neonate. In neonates, the normal adrenal glands are clearly visualized at US and consist of a hypoechoic cortex and a thin, echogenic medulla. The pattern of echogenicity of an adrenal hematoma depends again on its age. An early-stage hematoma appears solid with diffuse or inhomogeneous echogenicity. As liquefaction occurs, the mass demonstrates mixed echogenicity with a central hypoechoic region and eventually becomes completely anechoic and cystlike. Calcifications may be seen in the walls of the hematoma as early as 12 weeks after onset and gradually compact as the blood is absorbed. Color Doppler and power Doppler imaging allow confirmation of the avascular nature of the mass.

Dr. Alpana Joshi, Associate Professor, BYL Nair Hospital, Mumbai