J Korean Radiol Soc 1999 ; 40: 173-179

Imaging Findings ofNeonatal Adrenal Disorders 1

Hye-Kyung Yoon, M.D. , Bokyung Kim Han, M.D. , Min Hee Lee, M.D.

In newborn infants, normal adrenal glands are characterized by a relatively thin echogenic center surrounded by a thick , hypoechoic cortical rim as seen on ultrasound (US). Various disorders involving the neonatal adrenal gland include ad renal hemorrhage, hyperplasia, cys t, Wolman ’s disease , and congenital neuro­blastoma. Adrenal hemorrhage is the most common cause of an adrenal mass in the neonate, though differentiation between adrenal hemorrhage and neuroblastoma is in many cases difficult. We describe characteristic US, CT and MR imaging findings in neonates with various adrenal disorders .

Index words : Infants , newborn, genitourinary system Adrenal gland, abnormalities

Neonatal adrenal glands are clearJy demonstrated on uJtrasound (US) using high-freguency linear or phased array transducers. The normaJ neonataJ adrenaJ gland is clearly seen on postnatal abdominal sonograms,

consisting of an echolucent cortex and a thinner echogenic centraJ med ull a. AdrenaJ hemorrhage is the most common adrenal mass in neonates. US is used as the initiaJ mod aJity for diagnosing adrenaJ hemor­rhage , the appearance of which is varied and changes over time. Other less frequent disorders occurring in t he neonatal adrenal glands include congenital adrenal hyperplasia (adrenogenitaJ syndrome), lipoid adrenaJ hyperplasia, adrenaJ cyst, W oJman ’ s disease, and con­genital neuroblastoma. Computed tomography (CT) is excellent for depicting calcification or fat density associated with adrenallesions but beca use of the lack of retroperitoneal fat is less usefuJ for the demon­stration of normaJ adrenal glands. CT and /or magnetic resonance (MR) imaging may be helpful for evaJuating the extent and tissue characterization of an adrenal mass.

IDcpa rlmcnt of Rad io logy , Samsung Medi ca l Cc ntcr, Sungk y unk wa n Uni versity

Co ll egc 0 1' Med ici nc

Rcce ived Jun e 5, 1998 ; Accepled Se plember 8, 1998

Addrcss reprinl requcsls to: Hye-Kyu ng Yoon, M .D., Depar tment o fRad io logy, Sa msu ng Med ica l Cente r, ~ 50 Irwon-d o ng, Kangnam-gll, SCO ll l. 135-7 10, Korca Te I. 82-2-3410-25 18 Fax.82- 2-3410. 2559

Normal Neonatal Adrenal Glands

The appearance of neonatal adrenal glands varies; they may be lambdoid , V- or Y-shaped , and are rela tively large (1). On US, corticomeduJJ ary differen tiation is evident, with an outer echolucent cortex and a central echogenic line representing the medulla (Fig. lA and B). The cortex is prominent in normal newborn infants because of the presence of a thick transient feta l cortex, which involutes rapidly during the first three weeks of life and completes the synthesis of ma­ternally produced precursor steroids to make estrogens d uring the third trimester of pregnancy. After the neonatal period , the hypoechoic peripheral zone becomes smaller on US as the fetal cortex involutes. When ipsilateral renal agenesis or ectopia is present, the shape of adrenal gland is discoid and elongated (Fig. lC).

Adrenal Hemorrhage

Idiopathi c neonataJ adrenal hemorrhage is usuaJJy asymptomatic and freguentJy discovered as an inci­dentaJ finding on US (1). A large baby , difficult deliv­ery , and perinatal hypoxia have been reported as pre­disposing factors in neonataJ adrenaJ hemorrhage. On US, hemorrhage can be echogenic , echolucent or

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Hye-Kyung Yoon , et al : Imaging Findings of Neonatal Adrenal Disorders

mixed in appearance, depending on its age (Fig. 2, 3)

The adrenal gland may be discernible in part or com

A

C

A

Fig. 2. Neonatal adrenal hemorrhage

pletely obliterated. A diagnosis of adrenal hemorrhage

is based on sequential US examinations and involves

B

B

Fig. 1. Normal adrenal glands in new born infants A. Abdominal US in a newborn infant shows lambda­shaped right adrenal gland (arrows) with thick echolucent cortex and echogenic central line of the medulla. RK = right kidney . B. US with prone position in another newborn infant demonstrates large and thick limbs of the adrenal gland (arrows). The corticomedullary differentiation is clearly seen. C. Longitudinal US through the right renal fossa shows the elongated adrenal gland (arrow). In this case, right kidney (not shown) was seen in lower abdominal cav때 and was fused with the lower pole of left kidney (crossed fused ectopyl

A. Longitudinal US shows left adrenal hemorrhage (calipers) with mixed solid and cystic appearance. Note relative preser­vation ofthe normal triangular shape. LK = left kidney. B. Three months later, left adrenal hemorrhage seen on the figure A is completely resolved.

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J Korean Radiol Soc 1999; 40: 173-179

demonstration of liquefaction and regression. Calcifi

cation at its periphery is common (Fig. 3C). Due to the

paramagnetic effect of methemoglobin, MR imaging

(Fig. 3B) clearly shows adrenal hemorrhage of high sig­

nal intensity on precontrast Tl-weighted images.

A

C

A Fig. 4. Adrenal med 1I11 ary hemorrhage in a newborn

Adrenal hemorrhage may involve only a part of the

adrenal gland even when normal contour is preserved (2). When it primarily involves the adrenal medulla,

normal configuration of the gland and the cortex is

preserved (Fig. 4)

B

Fig. 3. Neonatal adrenal hemorrhage with calcification. A. Longitudinal sonogram shows adrenal hemorrhage (H) above right kidney (RK), with a predominantly solid appear­ance B. Tl -weighted axial MR image shows a large hyperintense hematoma (arrowheads) in the right adrenal gland with central isosignal intensity suggesting resolving hemorrhage. c. Two weeks later, right adrenal hemorrhage has decreased in size with eggshell-like calcification in the periphery of the resolving hematoma (arrowheads). RK = right kidney

B

Transverse (A) and longitudinal (B) US scans of the adrenal region show norma l hypoec hoic co rtices of both adrenal glands (arrowheads)‘ However, echogenic adrenal med lI 11ae (m) are markedly thi ckened.

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Hye-Kyung Yoon , et al : Imaging Findings of Neonatal Adrenal Disorders

Congenital Adrenal Hyperplasia

Enzymatic defects at any site of adrenal steroid biosynthesis result in cortisol deficiency and second­ary overproduction of pituitary corticotropin, which in turn overproduces androgens. Congenital adrenal hyperplasia or adrenogenital syndrome causes am­biguous genitalia, pseudohermaphroditism in females and an enlarged penis and precocious puberty in males. Deficiency of 21-hydroxylase is the most com­mon form of congenital adrenal hyperplasia, and dif­fuse or nodular enlargement of the adrenal cortex occurs in many but not all babies with this condition (2 , 3). US may show diffuse adrenal enlargement with a wrinkled , wavy, cerebriform appearance and loss of normal corticomedullary differentiation (Fig. 5). Oc casionally, adrenal enlargement may mimic adrenal mass but bilateral involvement with relative preser­vation of gland configuration can exclude adrenal

tumor (Fig. 5C and D)

Congenital Li poid Adrenal Hyperplasia

Conversion of cholesterol to pregnenolone is an es sential step in the synthesis of all adrenocortical hormones. Infants with 20, 22-desmolase deficiency cannot synthesize any glucocorticoid, mineralo­corticoid, or sex steroid. The adrenal glands are enlarged and filled with cholesterol and other lipids,

which explains echogenecity on US and hypodensity on CT scan (5) (Fig. 6)

Adrenal Cyst

Adrenal cysts may be parasitic, epitheliaL endo thelial or pseudocysts; true epithelium-lined adrenal cysts are rare in the neonate. Cystic lesions of the adrenal glands are usually pseudocysts (hemorrhagic cysts) secondary to resolving adrenal hemorrhage.

A B

Fig. 5. Congenital adrenal hyperplasia in a newborn girl with virilization and dark pigmentation Right (A) and left (8) adrenal glands show diffuse enlargement with cer­ebriform appearance (arrows). L =

liver, S = spleen. C. Transverse US in another female infant with congenital adrenal hyper­plasia reveals diffuse enlargement of bilateral adrenal glands (arrowheads). D. T2-weighted coronal MR image in the same patient to C shows diffuse enlargement of the adrenal glands (arrows) with preservation ofthe nor­mal triangular configuration

C D

τ ω

J Korean Radiol Soc 1999 ; 40: 173- 1 79

Adrenal cystic masses h ave been described in associ­

ation with complete or incomplete forms of Beckwith­

Wiedemann syndrome (6, 7) (Fig. 7) . Because an

adrenal cyst cannot be clearly distinguished from the

cystic neuroblastoma occurring in association with

Beckwith-Wiedemann syndrome, close observation, as

well as US or surgical con firmation , is needed .

Wolman ’ s Disease

Wolman ’ s disease is a fatal xanthomatosis of

autosomal recessive inheritance and is characterized

by failure to thrive, hepatosplenomegaly, vomiting, and steatorrhea. Uniform bilateral adrenal enlargement

with calcification is pathognomonic (8) . Calcification

Fig. 6. Congenitallipoid adrenal hyperplasia.

A

A

A. Longitudinal US scan of the left f1ank shows enlarged adrenal gland (arrows) above the left kidney (LK). The gland appears diffusely echogenic with loss of corticomed ullary differentiation. 8 . Unenhanced CT scan at the level of adrenal gland shows thickened both adrenal glands with low attenuation , indicating fatty infiltration

B c Fig. 7. Adrenal cystic mass in a newborn girl with Beckwith-Wiedemann syndrome Longitud inal US sca n (A) shows a large , well-demarcated cystic mass with homogeneous interna l echoes above the right kid ney (RK). T2-weighted (8) and postcontrast T l -weighted (C) coronal images show a large suprarenal cystic mass (M) wit h homogeneous high signal intensity on T2-weighted image without enhancing so lid portion. Right kidney (RK) is displaced and rotated inferiorly and media ll y. Surgical removal with histologic examination confirmed hemorrhagic cyst ofthe right ad rena l gland

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A 8

D E

A Fig. 9. Congenital neuroblastoma

Hye-Kyung Yoon. et al : Imaging Findings of Neonatal Adrenal Disorders

C

B

Fig. 8. Wolman disease in a 45-day­old boy . A. Plain radiograph shows triangular calcifications in both suprarenal regions (arrowheads) B. Transverse US scan shows calcifi cations along both adrenallimbs with acoustic shadowing (arrows) C. Unenhanced CT scan clearly shows extensive adrenal calcifications with lamellated appearance (arrows). Coronal Tl (0) and T2-weighted (E) MR images show bilateraL symmetri­cal enlargement of the adrenal glands (arrows) with alternating low and isosignal intensities suggesting lamel­lated calcifications. Note preservation of normal adrenal gland configur­atJOn.

A. Longitudinal US scan in a newborn girl shows a well-demarcated , homogeneously echogenic mass (M) above the right kid­ney (RK). Surgery confirmed neuroblastoma originating from the right adrenal gland. B. Extraadrena l neuroblastoma in a newborn baby. Transverse US scan shows a retrocaval mass (arrows) which is partly cys­tic and solid. At surgery , it was proved to be a retroperitoneal neuroblastoma with hemorrhage in the vicinity ofright adrenal gland . V = inferior vena cava , RK = right kidney

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J Korean Radiol Soc 1999; 40 : 173-179

throughout the glands is clearly demonstrated on plain

radiograph, US, and CT (Fig. 8) . On MR images, both

adrenal glands are diffusely thickened with linear iso

or hypointensity, suggesting calcification (Fig . 8 D and

E).

Congenital Neuroblastoma

Congenital neuroblastoma should be considered in

the differential diagnosis of a neonatal suprarenal

mass. Cystic neuroblastoma is more common during

the neonatal period than at any other age, though it

may be difficult or even impossible to differentiate

neonatal neuroblastoma from adrenal hemorrhage, es­

pecially when the tumor is cystic or hemorrhagic (9)

Ne uroblastoma tends to remain static over the first two

weeks of life as compared to adrenal hemorrhage. US

demonstrates a cystic or solid-appearing suprarenal

mass originating from the adrenal gland or paraver­

tebral sympathetic chain (Fig . 9).

References

1. Westra SJ, Zan inovic AC, Hal! TR, Kangaloo H, Boechat MI Imaging ofthe adrenal gland in children. RadioGraphics 1994 ; 14

1323- 1340

2. Cohen EK, Daneman A, Stringer DA, Soto G, Thorner P. Focal adrenal hemorrhage : a new ul trasonographic appeara nce ‘ Radi

%gy 1986; 16 1 ‘ 631-633

3. Sivit CJ, Hung W, Taylor GA, Catena LM, Browne-Jones C, Kushner DC. Sonograp hy in neonatal congenital adrenal hyper­plasia. AJR 199 1 ; 156: 14 1- 143

4 . Avni EF, Rypens F, Smet MH, Galetty E. Sonographic demon­stration of congenita l adrenal hyperplasia in the neonate: the cer ebriform pattern . Pediatr Radio/ 1993; 23 : 88-90

5. Ogata T, Jshikawa K, Kohda E, Matsuo N. Computed tomography in the early detection of congenital lipoid adrenal hyperplasia Pediatr Radio1 1988; 18: 360-361

6. McClauley RGK, Beckwith JB, Elias ER, Faerber EN, Prewitt LH, Jr, Berdon WE. Benign hemorrhagic macrocysts in Beckwith­Wi edemann Syndrome. A JR 1991 ; 157: 549-552

7. Akata D, Haliloglu M, Ozmen MN, Akhan O. Bi lateral cystic adrena l masses in the neonate associated with the incomplete form ofBeckwith-Wiedemann syndrome. Pediatr Radiol 1997; 27: 1-2

8. Duttton RV. Wolman ’ 5 disease: ultrasonographic and computed tomographic diagnosis. Pediatr Radiol 1985; 15 : 144-146

9. Hendry GMA. Cystic neuroblastoma ofthe ad renal gland : a poten tial source of error in ultraso nic diagnos is. Pediatr Radiol 1982; 12

204-206

대한방시선의학회XI1999 ; 40: 1 73-1 79

신생아부신질환의 영상소견

l 성균관대학교의과대학삼성의료원방사선과

윤혜경·검보경·이민희

신생아의 정상부신은초음파에서 두터운저 에코의 피질과앓은고 에코의 수질로보이는것이 특정이다.신생아

의 부신을침범하는질환은다양하며 부신출혈， 부신과증식，냥종，선천성 신경 아세포종등이 있다.이중부신출혈이

가장 흔한데，신경아세포종과의 감별이 어려운경우도있다.저자들은신생아의 여러 부신질환에서 특정적인초음

파，전산화단순촬영，자기공명영상소견을보고하고자하였다.

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삼성제일병원 조음파 연수교육 안내

4th REFRESHER COURSE ON OBSTETRIC SONOGRAPHY -FETAL THORAX AND ABDOMEN-

8: 30- 9 : 00 똑 야

9 : 00 - 9: 30 Normal sonographic anatomy 01 the letal thorax and abdomen

9 :30- 9:50 Fetallung mass

9 : 50 -1 0 : 30 Delects 01 the diaphragm and abdominal wall in the letus

10 : 50-11 :10 Fetuses with pleural effusion and ascites

11 : 10 -11 : 40 Systematic approach to letal i ntestinal obstruction

11 :40-12 : 10 Differential diagnosisolletal abdominal masses

13 : 30 - 14 : 10 Postnatal treatment and outcome 01 the letuses with thoracic

and abdominal abnormal ities

14 : 10 -14 : 40 Obstructive diseases 01 the letal urinary tract

14: 40 -15 ‘ 00 Signilicance 01 mild dilatation olletal renal pelvis

15: 20 -15 ’ 50 Pathology 01 cystic disease 01 kidneys

15 : 50 - 16 : 1 0 Sonog raphy 01 the cystic diseases 01 the letal ki dneys

16 : 10 -16 : 40 Postnatal treatment and outcome 01 the letuses with urinary

tract abnormalities

16 : 40 -17 : 00 Fetal interventional procedures lor thoracic and

abdominal abnormalities

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일 시 : 1999년 4월 18일( 일)

장 소:삼성서울병원 대강당(일원동소재)

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연수교육책임자 : 이영호(성균관의대 삼성제일병원 진단방사선과 2262-7145) 연수핑점 :6점

연수교육등록 : 사전등록( 마감일 : 1999년 4월 16일)

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