Clinical Radiology (1991) 43, 88-90
CT and MR Appearance of Focal Nodular Hyperplasia of the Liver in Children with Biliary Atresia K. OHTOMO,
Y. I T A I ,
K. HASIZUME*,
N. KOSAKA
and M. IIO
Departments o f Radiology and * Paediatric Surgery, University of Tokyo, Tokyo, Japan Two children with biliary atresia are described in whom focal nodular hyperplasia of the liver occurred following portoenterostomy. The lesions were low- or iso-dense on unenhanced CT and became hypodense post-contrast enhancement. There was normal 99mTc phytate on hepatic colloid scintigraphy. On T2-weighted spin echo M R images, there was increased signal intensity within the masses, and the surrounding liver parenchyma was divided by linear septa in one of the two cases. Ohtomo, K., Itai, Y., Hasizume, K., Kosaka, N. & Iio, M. (1991). Clinical Radiology, 43, 88-90. C T a n d M R A p p e a r a n c e o f F o c a l N o d u l a r H y p e r p l a s i a o f the Liver in C h i l d r e n with Biliary A t r e s i a
H e p a t i c p o r t o e n t e r o s t o m y a n d its m o d i f i c a t i o n s has been widely accepted as the o n l y effective surgical p r o c e d u r e for biliary atresia. A l t h o u g h long survival times have been r e p o r t e d , various c o m p l i c a t i o n s such as hepatic insufficiency with biliary cirrhosis a n d p o r t a l h y p e r t e n s i o n have been described several years after corrective surgery ( M i y a t a et al., 1974; K a s a i et al., 1981). In this article we r e p o r t two children with bitiary atresia, in w h o m focal n o d u l a r h y p e r p l a s i a ( F N H ) o f the liver c o m p l i c a t e d their p o s t - o p e r a t i v e courses.
CASE REPORTS
Case 1. A 9-year-old girl with biliary atresia was admitted for an episode of cholangitis. Portoenterostomy was carried out when she was 3 months old. Second and third operations were performed to correct anastomotic strictures. Portal hypertension developed after several episodes of cholangitis. Partial splenic embolizatlon and endoscopic sclerotherapy were carried out for oesophageal varices when she was 8 years old. Abdominal ultrasound disclosed a 6 cm hyperechoic lesion in the right lobe of the liver. Unenhanced CT demonstrated an area of isodensity which became hypo-dense relative to the adjacent liver on intravenous bolus enhancement (Fig. la). MR images were obtained using a 1.5 Tesla superconducting system (Siemens). On Tl-weighted spin echo images (TR/TE 600/17), linear low intensity septa separated the liver parenchyma and the mass was isointense with liver. T2weighted spin echo images (TR/TE 2000/09) demonstrated slight increased signal intensity of the mass (Fig. lb, c). No area of photon deficiency was noted on hepatic colloid scintigraphy. Selective hepatic arteriography disclosed a hypervascular mass with a fine lace-like reticular pattern of small vessels (Fig. ld). The radiological diagnosis was FNH. Pathological examination of the specimens obtained by cutting needle biopsy confirmed the diagnosis. Case 2. A five-year-old girl with biliary atresia was admitted for evaluation of portal hypertension. Portoenterostomy was carried out when she was 5 months old. She had several episodes of cholangitis. Unenhanced CT demonstrated a 5 cm isodense mass with a hypodense rim in the right lobe of the liver (Fig. 2a). On Tl-weighted spin echo images (TR/TE 500/17), the mass was slightly hyperintense and was surrounded by a hypointense rim (Fig. 2b). T2-weighted spin echo images (TR/TE 2000/90) demonstrated inhomogeneous high signals within the mass (Fig. 2e). Homogeneous uptake was noted within the mass on hepatic colloid scintigraphy using 99mTcphytate (Fig. 2d). A diagnosis of FNH was made radiologically and no significant change was noted on CT one year later.
Correspondence to: Dr K. Ohtomo, Department of Radiology, University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo, Japan 113.
DISCUSSION F o c a l n o d u l a r h y p e r p l a s i a is a rare benign lesion which is c o m p o s e d o f hepatocytes, K u p f e r cells, bile duct elements a n d fibrous connective tissue ( K n o w k e s a n d Wolff, 1976; G o l d et al., 1978). T h e a e t i o l o g y is p o o r l y u n d e r s t o o d a l t h o u g h it has been p o s t u l a t e d t h a t this lesion represents a regenerative response to v a s c u l a r injury. T h e highest prevalence is in y o u n g w o m e n , b u t the lesion c a n occur at any age. In a review o f the l i t e r a t u r e ( M c l o u g h l i n et al., 1973; K n o w k e s a n d Wolff, 1976; G o l d et al., 1978; A t k i n s o n et al., 1980; M a r k o w i t z et al., 1980), 18 o f the cases occurred within the p a e d i a t r i c age range. F N H is usually discovered as a n a s y m p t o m a t i c m a s s in b o t h a d u l t s a n d children. I n a review o f the cases o f F N H , 58% h a d n o r m a l colloid scintigrams ( R o g e r s et al., 1981). This i m p o r t a n t finding occurs because F N H c o n t a i n s K u p f e r cells. N e a r l y 90% o f r e p o r t e d cases o f F N H were h y p e r v a s c u l a r on h e p a t i c a n g i o g r a m s . T h e lesions were s h a r p l y m a r g i nated, h o m o g e n e o u s or septated, s o m e with a b n o r m a l vessels a r r a n g e d in a spoke-like p a t t e r n ( R o g e r s et al., 1981). O n CT, F N H has been r e p o r t e d to be iso- or h y p o d e n s e before e n h a n c e m e n t a n d iso- or h y p e r d e n s e after e n h a n c e m e n t ( R o g e r s et al., 1981). Recently the M R findings o f F N H have been r e p o r t e d (Butch et al., 1986; M a t t i s o n et al., 1987; Schiebler et al., 1987). T h e lesion is usually iso-intense o n T l - w e i g h t e d spin echo i m a g e s a n d slightly h y p e r i n t e n s e on T2-weighted spin echo images. It is h o m o g e n o u s except for a central fibrotic scar which is o f low intensity on T l - w e i g h t e d images a n d o f high intensity on T2-weighted images. M a t t i s o n et al. (1987) have r e p o r t e d that the hyperintense fibrotic scar in F N H c o n t a i n s bile ducts a n d v a s c u l a r channels in a d d i t i o n to fibrotic tissue. This finding is i m p o r t a n t in differentiating F N H f r o m o t h e r hepatic m a s s lesions in which the scar is c o m p o s e d o f p u r e fibrosis a n d is d e m o n s t r a t e d as an a r e a o f low intensity on b o t h T l - w e i g h t e d a n d T 2 - w e i g h t e d spin echo images ( M a t t i s o n et al., 1987). T h e a p p e a r a n c e s o f F N H in o u r two cases were c o m p a t i b l e with the r e p o r t e d features except fot the C T a n d M R findings in case 2 in w h o m the lesion was h y p e r i n t e n s e with a h y p o i n t e n s e rim on T l - w e i g h t e d spin echo i m a g e s a n d i n h o m o g e n e o u s l y h y p e r i n t e n s e on T2weighted spin echo images. W e c a n n o t suggest a n y r e a s o n
89
FNH OF THE LIVER IN CHILDREN WITH BILIARY ATRESIA
(a)
(b)
(c)
(d)
Fig. 1- Case 1. (a) Contrast enhanced CT demonstrates a 6 cm low density mass in the right lobe of the liver. (b) The mass is seen as an isointense area on a Tl-weighted spin echo image (TR/TE 600/17 ms). The rest of liver parenchyma was divided by linear hypointense septa. (c) T2-weighted spin echo image (TR/TE 2000/90) shows the slightly higher intensity in the mass. (d) The mass is hypervascular on a hepatic arteriogra~n.
Fig.
2-(a)
Fig. 2 (b)
90
CLINICAL RADIOLOGY
.2
(c)
.
.
.
.
.
.
.
.
.
(d)
Fig. 2 - Case 2. (a) Unenhanced CT demonstrates an iso-dense mass with faint low dense rim (arrows) in the right lobe of the liver. (b) The mass is slightly hyperintense on a Tl-weighted spin echo image (TR/TE 500/17) and a low-intensity rim is present around it. (c) The mass has a slightly increased signal intensity on a T2-weighted spin echo image (TR/TE 2000/90) (arrows). (d) Normal uptake within the mass on a hepatic colloid scintigram using 99mTc phytate.
f o r the h y p e r i n t e n s i t y o n T l - w e i g h t e d i m a g e s . T h e r i m like s t r u c t u r e s , also d e m o n s t r a t e d o n u n e n h a n c e d C T , p r o b a b l y c o r r e s p o n d to a p s e u d o c a p s u t e w h i c h is t h e result o f c o m p r e s s i o n a t r o p h y o f s u r r o u n d i n g p a r e n c h y m a (Begg a n d Berry, 1953). I n c a s e 1, t h e l i n e a r s e p t a in the s u r r o u n d i n g liver p a r e n c h y m a o n M R p r o b a b l y reflects m a c r o s c o p i c d e f o r m i t y d u e to liver fibrosis w h i c h usually complicates the post-operative course of biliary atresia. T o o u r k n o w l e d g e , t h e r e h a s b e e n n o r e p o r t e d case o f F N H in a s s o c i a t i o n w i t h b i l i a r y a t r e s i a a l t h o u g h r e g e n e r a t i v e n o d u l e s w e r e s h o w n p a t h o l o g i c a l l y in o n e o f 16 p a t i e n t s in w h o m a s e c o n d l a p a r o t o m y w a s c a r r i e d o u t a f t e r the c o r r e c t i v e o p e r a t i o n f o r b i l i a r y a t r e s i a ( K a s a i et al., 1981) a n d f u r t h e r s i m i l a r cases m a y be d i s c o v e r e d among long survivors with biliary atresia after portoenterostomy.
REFERENCES Atkinson, GO, Kordroff, M, Sones, PJ & Gay, BB (1980)• Focal nodular hyperplasia of the liver in children: a report of three new cases. Radiology, 137, 171-174. Begg, CF & Berry, WH (1953). Isolated nodules of regenerative hyperplasia of the liver. American Journal of Clinical Pathology, 23, 447-463. Butch, R J, Stark, DD & Malt RA (1986). MR imaging of hepatic focal
nodular hyperplasia. Journal of Computer Assisted Tomography. 10, 874-877. Gold, JH, Guzman, IJ & Rosai, J (1978). Benign tumor of the liver: pathologic examination of 45 cases. American Journal of Clinical Pathology, 70, 6-17. Kasai, M, Okamoto, A, Ohi, R, Yabe, K & Matsumura, Y (1981). Changes of portal vein pressure and intrahepatic blood vessels after surgery for biliary atresia. Journal of Pediatric Surgery, 16, 152-159. Knowkes, DM & Wolff, M (1976). Focal nodular hyperplasia of the liver: a clinicopathologic study and review of the literature. Human Pathology, 7, 533-545. Markowitz, R., Harcke, T, Ritche, WGM & Huff, DS (1980). Focal nodular hyperplasia of the liver in a child with sickle cell anemia. American Journal of Roentgenology, 134, 594-597. Mattison, GR, Glazer, GM, Quint, LE, Francis, IR, Bree, RL & Ensminger, WD (1987). MR imaging of hepatic focal nodular hyperplasia: characterization and distinction from primary malignant hepatic tumors. American Journal of Roentgenology, 148, 711715. McLoughlin, M J, Colapinto, RF, Gilday, DL, Hobbs BB Korobkin, M, McDonald, Pet al. (1973). Focal nodular hyperplasia of the liver; angiography and radioisotope scanning. Radiology, 107, 257 263. Miyata, M, Satani, M, Ueda, T & Okamoto, E (1974). Long-term results of hepatic portoenterostomy for biliary atresia: Special reference to postoperative portal hypertension. Surgery, 76, 234 237. Rogers, JV, Mack, LA, Freeny, PC, Johnson, ML & Sones, PJ (1981). Hepatic focal nodular hyperplasia: angiography, CT, sonography, and scintlgraphy. American Journal of Roentgenology, 137, 983-990. Schiebler, ML, Kressel, HY, Saul, SH, Yeager, BA, Axel, L & Gefter, WB (1987). MR imaging of focal nodular hyperplasia of the liver. Journal of Computer Assisted Tomography, 11, 651 654.
CT and MR Appearance of Focal Nodular Hyperplasia of the Liver in Children with Biliary Atresia K. OHTOMO,
Y. I T A I ,
K. HASIZUME*,
N. KOSAKA
and M. IIO
Departments o f Radiology and * Paediatric Surgery, University of Tokyo, Tokyo, Japan Two children with biliary atresia are described in whom focal nodular hyperplasia of the liver occurred following portoenterostomy. The lesions were low- or iso-dense on unenhanced CT and became hypodense post-contrast enhancement. There was normal 99mTc phytate on hepatic colloid scintigraphy. On T2-weighted spin echo M R images, there was increased signal intensity within the masses, and the surrounding liver parenchyma was divided by linear septa in one of the two cases. Ohtomo, K., Itai, Y., Hasizume, K., Kosaka, N. & Iio, M. (1991). Clinical Radiology, 43, 88-90. C T a n d M R A p p e a r a n c e o f F o c a l N o d u l a r H y p e r p l a s i a o f the Liver in C h i l d r e n with Biliary A t r e s i a
H e p a t i c p o r t o e n t e r o s t o m y a n d its m o d i f i c a t i o n s has been widely accepted as the o n l y effective surgical p r o c e d u r e for biliary atresia. A l t h o u g h long survival times have been r e p o r t e d , various c o m p l i c a t i o n s such as hepatic insufficiency with biliary cirrhosis a n d p o r t a l h y p e r t e n s i o n have been described several years after corrective surgery ( M i y a t a et al., 1974; K a s a i et al., 1981). In this article we r e p o r t two children with bitiary atresia, in w h o m focal n o d u l a r h y p e r p l a s i a ( F N H ) o f the liver c o m p l i c a t e d their p o s t - o p e r a t i v e courses.
CASE REPORTS
Case 1. A 9-year-old girl with biliary atresia was admitted for an episode of cholangitis. Portoenterostomy was carried out when she was 3 months old. Second and third operations were performed to correct anastomotic strictures. Portal hypertension developed after several episodes of cholangitis. Partial splenic embolizatlon and endoscopic sclerotherapy were carried out for oesophageal varices when she was 8 years old. Abdominal ultrasound disclosed a 6 cm hyperechoic lesion in the right lobe of the liver. Unenhanced CT demonstrated an area of isodensity which became hypo-dense relative to the adjacent liver on intravenous bolus enhancement (Fig. la). MR images were obtained using a 1.5 Tesla superconducting system (Siemens). On Tl-weighted spin echo images (TR/TE 600/17), linear low intensity septa separated the liver parenchyma and the mass was isointense with liver. T2weighted spin echo images (TR/TE 2000/09) demonstrated slight increased signal intensity of the mass (Fig. lb, c). No area of photon deficiency was noted on hepatic colloid scintigraphy. Selective hepatic arteriography disclosed a hypervascular mass with a fine lace-like reticular pattern of small vessels (Fig. ld). The radiological diagnosis was FNH. Pathological examination of the specimens obtained by cutting needle biopsy confirmed the diagnosis. Case 2. A five-year-old girl with biliary atresia was admitted for evaluation of portal hypertension. Portoenterostomy was carried out when she was 5 months old. She had several episodes of cholangitis. Unenhanced CT demonstrated a 5 cm isodense mass with a hypodense rim in the right lobe of the liver (Fig. 2a). On Tl-weighted spin echo images (TR/TE 500/17), the mass was slightly hyperintense and was surrounded by a hypointense rim (Fig. 2b). T2-weighted spin echo images (TR/TE 2000/90) demonstrated inhomogeneous high signals within the mass (Fig. 2e). Homogeneous uptake was noted within the mass on hepatic colloid scintigraphy using 99mTcphytate (Fig. 2d). A diagnosis of FNH was made radiologically and no significant change was noted on CT one year later.
Correspondence to: Dr K. Ohtomo, Department of Radiology, University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo, Japan 113.
DISCUSSION F o c a l n o d u l a r h y p e r p l a s i a is a rare benign lesion which is c o m p o s e d o f hepatocytes, K u p f e r cells, bile duct elements a n d fibrous connective tissue ( K n o w k e s a n d Wolff, 1976; G o l d et al., 1978). T h e a e t i o l o g y is p o o r l y u n d e r s t o o d a l t h o u g h it has been p o s t u l a t e d t h a t this lesion represents a regenerative response to v a s c u l a r injury. T h e highest prevalence is in y o u n g w o m e n , b u t the lesion c a n occur at any age. In a review o f the l i t e r a t u r e ( M c l o u g h l i n et al., 1973; K n o w k e s a n d Wolff, 1976; G o l d et al., 1978; A t k i n s o n et al., 1980; M a r k o w i t z et al., 1980), 18 o f the cases occurred within the p a e d i a t r i c age range. F N H is usually discovered as a n a s y m p t o m a t i c m a s s in b o t h a d u l t s a n d children. I n a review o f the cases o f F N H , 58% h a d n o r m a l colloid scintigrams ( R o g e r s et al., 1981). This i m p o r t a n t finding occurs because F N H c o n t a i n s K u p f e r cells. N e a r l y 90% o f r e p o r t e d cases o f F N H were h y p e r v a s c u l a r on h e p a t i c a n g i o g r a m s . T h e lesions were s h a r p l y m a r g i nated, h o m o g e n e o u s or septated, s o m e with a b n o r m a l vessels a r r a n g e d in a spoke-like p a t t e r n ( R o g e r s et al., 1981). O n CT, F N H has been r e p o r t e d to be iso- or h y p o d e n s e before e n h a n c e m e n t a n d iso- or h y p e r d e n s e after e n h a n c e m e n t ( R o g e r s et al., 1981). Recently the M R findings o f F N H have been r e p o r t e d (Butch et al., 1986; M a t t i s o n et al., 1987; Schiebler et al., 1987). T h e lesion is usually iso-intense o n T l - w e i g h t e d spin echo i m a g e s a n d slightly h y p e r i n t e n s e on T2-weighted spin echo images. It is h o m o g e n o u s except for a central fibrotic scar which is o f low intensity on T l - w e i g h t e d images a n d o f high intensity on T2-weighted images. M a t t i s o n et al. (1987) have r e p o r t e d that the hyperintense fibrotic scar in F N H c o n t a i n s bile ducts a n d v a s c u l a r channels in a d d i t i o n to fibrotic tissue. This finding is i m p o r t a n t in differentiating F N H f r o m o t h e r hepatic m a s s lesions in which the scar is c o m p o s e d o f p u r e fibrosis a n d is d e m o n s t r a t e d as an a r e a o f low intensity on b o t h T l - w e i g h t e d a n d T 2 - w e i g h t e d spin echo images ( M a t t i s o n et al., 1987). T h e a p p e a r a n c e s o f F N H in o u r two cases were c o m p a t i b l e with the r e p o r t e d features except fot the C T a n d M R findings in case 2 in w h o m the lesion was h y p e r i n t e n s e with a h y p o i n t e n s e rim on T l - w e i g h t e d spin echo i m a g e s a n d i n h o m o g e n e o u s l y h y p e r i n t e n s e on T2weighted spin echo images. W e c a n n o t suggest a n y r e a s o n
89
FNH OF THE LIVER IN CHILDREN WITH BILIARY ATRESIA
(a)
(b)
(c)
(d)
Fig. 1- Case 1. (a) Contrast enhanced CT demonstrates a 6 cm low density mass in the right lobe of the liver. (b) The mass is seen as an isointense area on a Tl-weighted spin echo image (TR/TE 600/17 ms). The rest of liver parenchyma was divided by linear hypointense septa. (c) T2-weighted spin echo image (TR/TE 2000/90) shows the slightly higher intensity in the mass. (d) The mass is hypervascular on a hepatic arteriogra~n.
Fig.
2-(a)
Fig. 2 (b)
90
CLINICAL RADIOLOGY
.2
(c)
.
.
.
.
.
.
.
.
.
(d)
Fig. 2 - Case 2. (a) Unenhanced CT demonstrates an iso-dense mass with faint low dense rim (arrows) in the right lobe of the liver. (b) The mass is slightly hyperintense on a Tl-weighted spin echo image (TR/TE 500/17) and a low-intensity rim is present around it. (c) The mass has a slightly increased signal intensity on a T2-weighted spin echo image (TR/TE 2000/90) (arrows). (d) Normal uptake within the mass on a hepatic colloid scintigram using 99mTc phytate.
f o r the h y p e r i n t e n s i t y o n T l - w e i g h t e d i m a g e s . T h e r i m like s t r u c t u r e s , also d e m o n s t r a t e d o n u n e n h a n c e d C T , p r o b a b l y c o r r e s p o n d to a p s e u d o c a p s u t e w h i c h is t h e result o f c o m p r e s s i o n a t r o p h y o f s u r r o u n d i n g p a r e n c h y m a (Begg a n d Berry, 1953). I n c a s e 1, t h e l i n e a r s e p t a in the s u r r o u n d i n g liver p a r e n c h y m a o n M R p r o b a b l y reflects m a c r o s c o p i c d e f o r m i t y d u e to liver fibrosis w h i c h usually complicates the post-operative course of biliary atresia. T o o u r k n o w l e d g e , t h e r e h a s b e e n n o r e p o r t e d case o f F N H in a s s o c i a t i o n w i t h b i l i a r y a t r e s i a a l t h o u g h r e g e n e r a t i v e n o d u l e s w e r e s h o w n p a t h o l o g i c a l l y in o n e o f 16 p a t i e n t s in w h o m a s e c o n d l a p a r o t o m y w a s c a r r i e d o u t a f t e r the c o r r e c t i v e o p e r a t i o n f o r b i l i a r y a t r e s i a ( K a s a i et al., 1981) a n d f u r t h e r s i m i l a r cases m a y be d i s c o v e r e d among long survivors with biliary atresia after portoenterostomy.
REFERENCES Atkinson, GO, Kordroff, M, Sones, PJ & Gay, BB (1980)• Focal nodular hyperplasia of the liver in children: a report of three new cases. Radiology, 137, 171-174. Begg, CF & Berry, WH (1953). Isolated nodules of regenerative hyperplasia of the liver. American Journal of Clinical Pathology, 23, 447-463. Butch, R J, Stark, DD & Malt RA (1986). MR imaging of hepatic focal
nodular hyperplasia. Journal of Computer Assisted Tomography. 10, 874-877. Gold, JH, Guzman, IJ & Rosai, J (1978). Benign tumor of the liver: pathologic examination of 45 cases. American Journal of Clinical Pathology, 70, 6-17. Kasai, M, Okamoto, A, Ohi, R, Yabe, K & Matsumura, Y (1981). Changes of portal vein pressure and intrahepatic blood vessels after surgery for biliary atresia. Journal of Pediatric Surgery, 16, 152-159. Knowkes, DM & Wolff, M (1976). Focal nodular hyperplasia of the liver: a clinicopathologic study and review of the literature. Human Pathology, 7, 533-545. Markowitz, R., Harcke, T, Ritche, WGM & Huff, DS (1980). Focal nodular hyperplasia of the liver in a child with sickle cell anemia. American Journal of Roentgenology, 134, 594-597. Mattison, GR, Glazer, GM, Quint, LE, Francis, IR, Bree, RL & Ensminger, WD (1987). MR imaging of hepatic focal nodular hyperplasia: characterization and distinction from primary malignant hepatic tumors. American Journal of Roentgenology, 148, 711715. McLoughlin, M J, Colapinto, RF, Gilday, DL, Hobbs BB Korobkin, M, McDonald, Pet al. (1973). Focal nodular hyperplasia of the liver; angiography and radioisotope scanning. Radiology, 107, 257 263. Miyata, M, Satani, M, Ueda, T & Okamoto, E (1974). Long-term results of hepatic portoenterostomy for biliary atresia: Special reference to postoperative portal hypertension. Surgery, 76, 234 237. Rogers, JV, Mack, LA, Freeny, PC, Johnson, ML & Sones, PJ (1981). Hepatic focal nodular hyperplasia: angiography, CT, sonography, and scintlgraphy. American Journal of Roentgenology, 137, 983-990. Schiebler, ML, Kressel, HY, Saul, SH, Yeager, BA, Axel, L & Gefter, WB (1987). MR imaging of focal nodular hyperplasia of the liver. Journal of Computer Assisted Tomography, 11, 651 654.
