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Anomalous arrangement of the pancreatobiliary ductal system in patients with a choledochal cyst
Anomalous Arrangement of the Pancreatobiliary Ductal System In Patients With a Choledochal Cyst
Takuji Todani, MD, Kagawa, Japan Yasuhiro Watanabe, MD, Kagawa, Japan Tadashi Fujii, MD, Kagawa, Japan Sadashlge Uemura, MD, Kagawa, Japan
In anomalous arrangements of the pancreatobiliary ductal system, the union of the pancreatic duct and common bile duct is generally located a distance away from the duodenum with a long common channel resulting in reflux of pancreatic juice into the bile duct due to the absence of the Oddi muscle around the union. However, more complicated forms on this junction have been observed in a few instances, and the classification of anomalies of the pancreatobiliary ductal system proposed by some investigators is still controversial [1,2]. Anomalies of ‘this junction have recently been indicated as a possible pathogenesis of choledochal cyst [3]. Since the concept of this anomaly was introduced, slight dilatation of the bile duct, relapsing pancreatitis, .and perforation of the choledochus have also become objects of attention in relation to choledochal cyst due to the fact that these conditions tend to include this anomaly with few exceptions. The purpose of this paper is to report our experience with 39 patients with a choledochal cyst, of whom 38 had an anomalous arrangement of the pancreatobiliary ductal system, and to discuss the relationship between the anomalies and our clinical findings. Material and Methods During a 10 year period, 39 children and young adults with a choledochal cyst were treated in Okayama University Hospital and Kagawa Medical School. Twenty of the patients were less than 15 years of age, and the ratio of female to male patients was 2.5:1. The junction of the pancreatobiliary ductal system was examined by endoscopic retrograde cholangiopancreatography or operative cholFromtheMni ofPediatric Surgery. Kagawa Medical school, Kagawa. Japan. Requests for reprintsshould be addressed to Takuji Todani, MD, Department of Pediatric Surgery, Kagawa Medical School, 1750-l. Miki. Kitagun. Kagawa 761-07. Japan. 672
angiography. The angle of the pancreatobiliary junction was measured as viewed frontally, and clinical manifestations, such as the type of extrahepatic ductal dilatation, intrahepatic involvement, general symptoms, and the amylase level of the bile within the cyst, were analyzed in relation to this angle. Cholangiograms of seven adults with intrahepatic ductal dilatation without a choledochal cyst, were examined, as were nine patients with hepatobiliary disorders other than a choledochal cyst and apparently normal junctions who served as control subjects. Results The average angle of the pancreatobiliary junction in nine patients who underwent laparotomies for hepatobiliary disorders other than a choledochal cyst and had apparently normal junctions, was a very acute 26.8 f 9.38 degrees (Figures 1 and 2). Seven patients with intrahepatic ductal dilatation in whom no extrahepatic ductal dilatation was observed also did not have anomalous arrangement of the pancreatobiliary ductal system (Figure 3). In the 39 patients with a choledochal cyst, however, two types of angles were observed: nearly right angles of 95.2 f 16.3 degrees seen in 25 patients (64.1 percent) and acute angles of 38.6 f 14.4 degrees, which were not as acute as those in patients without choledochal cysts, seen in 7 patients (17.9 percent) (Figures 1,4, and 5). Moreover, a complex union (Figure 6) between the pancreatic and biliary ducts, the angle of which could not be measured, was observed in six patients (15.4 percent), and an apparently normal junction was seen in only one patient (2.6 percent) with cylindrical dilatation of the choledochus. Cystic dilatation of the extrahepatic bile duct developed in 23 of 25 patients with right-angle junctions, 3 of 7.with acute-angle junctions, and all 6 with complex junctions. In contrast, cylindrical dilatation occurred in only 2 of the 25 patients with right-angle lhe AmericanJournal
ti Swpry
dwee 160
1 n
:s
:7
M : 36.6” SD : f14.4
El : 26.6” SD : fS.3
. n : 25 M : 95.2” SD: +16.3
. . .:*
i .
right angle
unions, 4 of 7 with acute-angle unions, and the 1 patient with a normal-angle junction. Stmoses of the tmuinal common duct just above the &m&ion were claa&ied into two groups: high grade and km grade (Figures 7,and 8). Cystic dilat&ion of tazScholedochus was seen in 22 of 24 patie& with high-grade stenosis and 5 of 9 patients with Iowqmde stenosis. Cylindrical dilatation was seen in 2 of24 patienta with high-grade stenosis and
acute angle
aontrol
4 of 8 patients with low-grade stemais. Length of the stenoses was also classified into twgl’gfmpszlong and short stenoses (Figures 7 and 8). All seven patients with long stenosis had cystic dilatation of the extrahepatic bile duct. Cylindrical diiatution was only observed in six patients with short stmosis. Nineteen patients with short stenosis had cystic dilatation.
Todani et
al
F&we 4. ?he rlghi-angk pmcreatobtllary)mctton wlthoui tntranlepatkntlmderwent hepetkdWatkntna28yearotdwoman. ~attheageofl47hlsdtdsrrgkOrsm was taken at ttm ttme ot the second operation whkh con&ted d exckkn ot the cyet with hepatkoje)mostomy at the hepatk htkm.
novn, 8. lhe co@ex-iintan pmmtomvmka
13~
oMfem0kpat&r&77Wan#ehfbl8chokr~ablatMfby en&scopk ntroarack cho&g sphV_k W c ie waMot mesrured A = pancmatkducf;B=hobnum choledocal cyst.
d&tatkn d
the lntra-i$atk
tlent.
The incidence of choledochal cyst accompanied with intrahepatic ductal dilatation was 31 of 39 patients (80 percent). Cystic dilatation of the intrahepatic ducts was seen in 8 of 18 patients with a rightangle junction, and in 1 of 5 patients with a complex union. Cylindrical dilatation was in 10 of 18 patients with a right-angle junction, in 4 of 5 patients with a complex junction, and in all 7 patients with an acute-angle junction (Table I). Cylindrical dilatation, however, disappeared in some patients after a definitive operation (excision of the extrahepatic ductal dilatation and biliary reconstruction). Clinical symptoms: Abdominal pain was observed in 22 of 25 patients with a right-angle junction,
674
in 6 of 7 with an acute-angle junction, and in 3 of 6 patients with a complex union. Abdominal tumors were observed in 16 of 25 patients with a right-angle junction and in 5 of 6 patients with a complex union. No patient with an acute-angle junction had an abdominal tumor. Jaundice was seen in 8 of 25 patients with a right-angle junction, in 1 of 7 patients with an acute-angle junction, and in 5 of 6 patients with a complex union. All 7 patients with cylindrical dilatation, and 24 of 32 patients with cystic dilatation complained of abdominal pain. An abdominal tumor was observed in 21 patients with cystic dilatation. Jaundice was seen in 11patients with the cystic form and in 3 with the cylindrical form. The amylase levels of the bile within the choledochal cyst were determined in 15 patients with choledochal cysts at the time of operation. High amylase levels were found in six of seven patients with a right-angle junction and in both patients with an acute-angle junction. In contrast, normal concentrations were seen in seven patients, six of whom had a complex union and one of whom had a right-angle junction. Six of these seven patients suffered from obstructive jaundice (Table II).
The Amdcan Jcumal
otSuwwy
Anomalous Arrangement
C-S
of the Pancreat~fllary
&m&m
The anomalous arrangement of the pancreatobiliary ductal system in patients with a choledochal cyst is generally regarded as a long common channel in which the pancreatobiliary union is apparently located outside of the duodenum. The normal length of the common channel in patients with unrelated problems has been reported to be less than 0.5 cm [4], but measurement of this channel might be inadequate because of variations in the age of the patients and differences in magnification between studies.
Cholangiograms taken operatively or endoscopically have not always indicated this long common channel and have shown very complicated ductal systems in a few patients, as in our study. Although classifications of anomalous junctions have been proposed, they are complicated, and the junctions in some instances are so complex that classification is difficult [2,3]. The angle of the pancreatobiliary junction as viewed frontally, however, can always be expressed objectively. Based on these angles, arrangement of the pancreatobiliary ductal
TABLE I
TABLE11
Aslolrrslcwr Ammgemml ol PetncYeetobHlary JtaWa~ and Types of Intrahepatk Duotal cvllndrical
Not Dilated
Total
8 0 1 0
10 7 4 1
7 0 1 0
25 7 6 1
9
22
8
39
CYStiC
RisMangle A-angle ComcIbX Normal
union
Total
vohmla 147, my
1984
Amyl~LOvekdBlso~~CYSthr15 Patients* HiOh
_~~~~ Right angle
l(l)
cMnpl9X
2 0
0 6 t5)
Total
8 (2)
7 (8)
Acute angle
Values in jaundlce. l
s (2)
LOW
parenthesesindicate
the number of patients with
675
Todani et
al
system in patients with a choledochal cyst was classified into four groups: right angle (95.2 f 16.3 degrees), acute angle (38.6 f 14.4 degrees), complex, and normal (26.8 f 9.3 degrees) (presented here in the order of incidence). The right-angle type, that may correspond to type A [3], in which the common duct drains into the pancreatic duct, and the complex type tend to be observed in patients with cystic dilatation of the extrahepatic bile duct. In contrast, the acute-angle type seems to be found mainly in patients with cylindrical dilatation and corresponds to type B [3], in which the pancreatic duct drains into the choledochus. This angle is not as acute as those in patients with normal unions. Apparently normal junctions have rarely been seen in patients with cylindrical dilatation of the choledochus [5]. Moreover, intrahepatic ductal dilatation without choledochal dilatation has usually shown a normal junction of the pancreatobiliary system and, therefore, cannot be classified into the same category as choledochal cyst as has been reported previously [6,7]. A stenosis of the choledochus just above the pancreatobiliary junction seems to determine the type of choledochal cyst: high-grade stenosis causes cystic dilatation of the extrahepatic duct, and low-grade stenosis causes cylindrical dilatation. The length of the stenosis, however, is perhaps more telling of the type of choledochal cyst than the grade of stenosis. A long stenosis causes cystic dilatation and a short stenosis causes cylindrical dilatation. These findings are thought to result from inflammatory changes due to a reflux of pancreatic juice into the choledothus. The incidence of choledochal cysts with intrahepatic involvement is apparently much higher than previously thought, and cylindrical dilatation of the intrahepatic duct is observed much more often than cystic dilatation. However, cylindrical dilatation of the intrahepatic duct might have developed secondarily, because it tends to grow smaller after definitive surgery. Therefore, only cystic dilatation of the intrahepatic bile duct, which was observed in a quarter of the patients with choledochal cysts, might develop primarily. Patients with a right-angle junction are likely to complain of abdominal pain and to have an abdominal tumor or occasionally jaundice, whereas patients with an acute-angle junction, especially when accompanied with cylindrical ductal dilatation, seem to only suffer from abdominal pain. In addition, those with a complex union tend to have jaundice and an abdominal mass. Highly elevated amylase levels in the bile within the cyst are frequently observed. This fact lends support to the reflux theory of the pathogenesis of bile duct dilatation. Regurgitation of pancreatic juice into the choledochus causes abdominal pain and leads to degeneration of the epithelium of the bile duct, as has been revealed in experimental studies [B-10]. However, a normal amylase level is often 676
found in patients with a complex union and obstructive jaundice. This phenomenon suggests that obstruction of the junction prevents reflux of pancreatic juice into the choledochus. Summary An anomalous arrangement of the pancreatobiliary ductal system is usually observed in patients with a congenital choledochal cyst and is represented by a long common channel distal to the pancreatobiliary junction. According to the angle of the pancreatobiliary junction, anomalous junctions can be classified into four groups: right angle, acute angle, complex union, and normal union (presented here in the order of their incidence). The right-angle type tends to have cystic dilatation of the choledochus, whereas the acute-angle type generally has cylindrical dilatation. However, the grade and length of the &en&s on the distal part of the choledochus tend to determine the type of choledochal cyst. Cystic dilatation is usually observed in patients with high-grade and long stenosis, whereas cylindrical dilatation is seen in those with low-grade and short stenosis. Patients with an acute angle junction seem to only suffer from abdominal pain, and those in the complex, union group tend to have jaundice and an abdominal tumor. A high amylase level in the bile within the cyst is observed frequently. In patients with obstructive jaundice, however, the amylase level is usually not elevated, because pancreatic juice cannot enter the choledochus. References 1. Oi I, Hara T. Abnormal connection between the choledochus and ths pancreatic duct In case of congenital choledochal cyst examined by endoscopk panaeatocfwlangbqapity. Jpn J Pedlatr Surg 1977;9:1121-29 (in Japanese). 2. Koml N, Udaka H, lkeda N, Kashlwagi Y. Congenftaf difatatlon of the billary tracts: new classlficatton and study with particular reference to ancmalous arrangement of the pancreaticoblliary ducts. Gastroenterol Jpn 1977;12:293. 3. Babbitt DP. Choledochal cyst: new etiologlcal concept based on anomalws relationships of common bile duct and pancreatic bulb. Ann Radio1 1989:12:231-40. 4. Jona JZ, Babbitt DP, Starshak RJ. LaPorta AJ, Gllcklich M, Cohen D. Anatomic observattons md etbkqk and sugkaj considerations in choledochal cyst. J Pediatr Surg 1979; 14:315-20. 5. Matsumoto Y. Mashita Ft. Anomalous arrangement of the pancreatobiltary ductal system. Stomach and Intestine 1981;18:1209-12. (in Japanese). 8. Todani T, Watanabe Y, Narusue M, Tabuchi K. Dkajima K. Congenttal bile duct cysts. Am J Surg 1977;134:293-9. 7. Todani T, Narusue M, Watanabe Y, Tabuchi K, Ckajlma K. Mnagemsntofcongennalch&MocM cystwfthj~tic involvement. Ann Sure 1978; 187:272-80. 8. lkede N. Experimental a& cllnical studies on anomalous relatkmsh@ in the pancreatkobtlfary duct. Tokushima J Exp Msd 1978;25:47-57. 9. Myano T, Suugs K. Suds K. Abnumal chol~eatkzo ductal junction related to the etiology of infanttle obstnrctlve jaundice diseases. J Pediatr Surg 1979; 14: 16-26. 10. Dhkawa H, Sawaguchi S. Yamazaki Y. lsftikawa A, Klkuchi M. Experimental analysls of the ill effect of anomalcus pancreaticoblllary ductal union. J Pedlatr Surg 1982;17:7-13. The Amertcan Journrl of Surm
Takuji Todani, MD, Kagawa, Japan Yasuhiro Watanabe, MD, Kagawa, Japan Tadashi Fujii, MD, Kagawa, Japan Sadashlge Uemura, MD, Kagawa, Japan
In anomalous arrangements of the pancreatobiliary ductal system, the union of the pancreatic duct and common bile duct is generally located a distance away from the duodenum with a long common channel resulting in reflux of pancreatic juice into the bile duct due to the absence of the Oddi muscle around the union. However, more complicated forms on this junction have been observed in a few instances, and the classification of anomalies of the pancreatobiliary ductal system proposed by some investigators is still controversial [1,2]. Anomalies of ‘this junction have recently been indicated as a possible pathogenesis of choledochal cyst [3]. Since the concept of this anomaly was introduced, slight dilatation of the bile duct, relapsing pancreatitis, .and perforation of the choledochus have also become objects of attention in relation to choledochal cyst due to the fact that these conditions tend to include this anomaly with few exceptions. The purpose of this paper is to report our experience with 39 patients with a choledochal cyst, of whom 38 had an anomalous arrangement of the pancreatobiliary ductal system, and to discuss the relationship between the anomalies and our clinical findings. Material and Methods During a 10 year period, 39 children and young adults with a choledochal cyst were treated in Okayama University Hospital and Kagawa Medical School. Twenty of the patients were less than 15 years of age, and the ratio of female to male patients was 2.5:1. The junction of the pancreatobiliary ductal system was examined by endoscopic retrograde cholangiopancreatography or operative cholFromtheMni ofPediatric Surgery. Kagawa Medical school, Kagawa. Japan. Requests for reprintsshould be addressed to Takuji Todani, MD, Department of Pediatric Surgery, Kagawa Medical School, 1750-l. Miki. Kitagun. Kagawa 761-07. Japan. 672
angiography. The angle of the pancreatobiliary junction was measured as viewed frontally, and clinical manifestations, such as the type of extrahepatic ductal dilatation, intrahepatic involvement, general symptoms, and the amylase level of the bile within the cyst, were analyzed in relation to this angle. Cholangiograms of seven adults with intrahepatic ductal dilatation without a choledochal cyst, were examined, as were nine patients with hepatobiliary disorders other than a choledochal cyst and apparently normal junctions who served as control subjects. Results The average angle of the pancreatobiliary junction in nine patients who underwent laparotomies for hepatobiliary disorders other than a choledochal cyst and had apparently normal junctions, was a very acute 26.8 f 9.38 degrees (Figures 1 and 2). Seven patients with intrahepatic ductal dilatation in whom no extrahepatic ductal dilatation was observed also did not have anomalous arrangement of the pancreatobiliary ductal system (Figure 3). In the 39 patients with a choledochal cyst, however, two types of angles were observed: nearly right angles of 95.2 f 16.3 degrees seen in 25 patients (64.1 percent) and acute angles of 38.6 f 14.4 degrees, which were not as acute as those in patients without choledochal cysts, seen in 7 patients (17.9 percent) (Figures 1,4, and 5). Moreover, a complex union (Figure 6) between the pancreatic and biliary ducts, the angle of which could not be measured, was observed in six patients (15.4 percent), and an apparently normal junction was seen in only one patient (2.6 percent) with cylindrical dilatation of the choledochus. Cystic dilatation of the extrahepatic bile duct developed in 23 of 25 patients with right-angle junctions, 3 of 7.with acute-angle junctions, and all 6 with complex junctions. In contrast, cylindrical dilatation occurred in only 2 of the 25 patients with right-angle lhe AmericanJournal
ti Swpry
dwee 160
1 n
:s
:7
M : 36.6” SD : f14.4
El : 26.6” SD : fS.3
. n : 25 M : 95.2” SD: +16.3
. . .:*
i .
right angle
unions, 4 of 7 with acute-angle unions, and the 1 patient with a normal-angle junction. Stmoses of the tmuinal common duct just above the &m&ion were claa&ied into two groups: high grade and km grade (Figures 7,and 8). Cystic dilat&ion of tazScholedochus was seen in 22 of 24 patie& with high-grade stenosis and 5 of 9 patients with Iowqmde stenosis. Cylindrical dilatation was seen in 2 of24 patienta with high-grade stenosis and
acute angle
aontrol
4 of 8 patients with low-grade stemais. Length of the stenoses was also classified into twgl’gfmpszlong and short stenoses (Figures 7 and 8). All seven patients with long stenosis had cystic dilatation of the extrahepatic bile duct. Cylindrical diiatution was only observed in six patients with short stmosis. Nineteen patients with short stenosis had cystic dilatation.
Todani et
al
F&we 4. ?he rlghi-angk pmcreatobtllary)mctton wlthoui tntranlepatkntlmderwent hepetkdWatkntna28yearotdwoman. ~attheageofl47hlsdtdsrrgkOrsm was taken at ttm ttme ot the second operation whkh con&ted d exckkn ot the cyet with hepatkoje)mostomy at the hepatk htkm.
novn, 8. lhe co@ex-iintan pmmtomvmka
13~
oMfem0kpat&r&77Wan#ehfbl8chokr~ablatMfby en&scopk ntroarack cho&g sphV_k W c ie waMot mesrured A = pancmatkducf;B=hobnum choledocal cyst.
d&tatkn d
the lntra-i$atk
tlent.
The incidence of choledochal cyst accompanied with intrahepatic ductal dilatation was 31 of 39 patients (80 percent). Cystic dilatation of the intrahepatic ducts was seen in 8 of 18 patients with a rightangle junction, and in 1 of 5 patients with a complex union. Cylindrical dilatation was in 10 of 18 patients with a right-angle junction, in 4 of 5 patients with a complex junction, and in all 7 patients with an acute-angle junction (Table I). Cylindrical dilatation, however, disappeared in some patients after a definitive operation (excision of the extrahepatic ductal dilatation and biliary reconstruction). Clinical symptoms: Abdominal pain was observed in 22 of 25 patients with a right-angle junction,
674
in 6 of 7 with an acute-angle junction, and in 3 of 6 patients with a complex union. Abdominal tumors were observed in 16 of 25 patients with a right-angle junction and in 5 of 6 patients with a complex union. No patient with an acute-angle junction had an abdominal tumor. Jaundice was seen in 8 of 25 patients with a right-angle junction, in 1 of 7 patients with an acute-angle junction, and in 5 of 6 patients with a complex union. All 7 patients with cylindrical dilatation, and 24 of 32 patients with cystic dilatation complained of abdominal pain. An abdominal tumor was observed in 21 patients with cystic dilatation. Jaundice was seen in 11patients with the cystic form and in 3 with the cylindrical form. The amylase levels of the bile within the choledochal cyst were determined in 15 patients with choledochal cysts at the time of operation. High amylase levels were found in six of seven patients with a right-angle junction and in both patients with an acute-angle junction. In contrast, normal concentrations were seen in seven patients, six of whom had a complex union and one of whom had a right-angle junction. Six of these seven patients suffered from obstructive jaundice (Table II).
The Amdcan Jcumal
otSuwwy
Anomalous Arrangement
C-S
of the Pancreat~fllary
&m&m
The anomalous arrangement of the pancreatobiliary ductal system in patients with a choledochal cyst is generally regarded as a long common channel in which the pancreatobiliary union is apparently located outside of the duodenum. The normal length of the common channel in patients with unrelated problems has been reported to be less than 0.5 cm [4], but measurement of this channel might be inadequate because of variations in the age of the patients and differences in magnification between studies.
Cholangiograms taken operatively or endoscopically have not always indicated this long common channel and have shown very complicated ductal systems in a few patients, as in our study. Although classifications of anomalous junctions have been proposed, they are complicated, and the junctions in some instances are so complex that classification is difficult [2,3]. The angle of the pancreatobiliary junction as viewed frontally, however, can always be expressed objectively. Based on these angles, arrangement of the pancreatobiliary ductal
TABLE I
TABLE11
Aslolrrslcwr Ammgemml ol PetncYeetobHlary JtaWa~ and Types of Intrahepatk Duotal cvllndrical
Not Dilated
Total
8 0 1 0
10 7 4 1
7 0 1 0
25 7 6 1
9
22
8
39
CYStiC
RisMangle A-angle ComcIbX Normal
union
Total
vohmla 147, my
1984
Amyl~LOvekdBlso~~CYSthr15 Patients* HiOh
_~~~~ Right angle
l(l)
cMnpl9X
2 0
0 6 t5)
Total
8 (2)
7 (8)
Acute angle
Values in jaundlce. l
s (2)
LOW
parenthesesindicate
the number of patients with
675
Todani et
al
system in patients with a choledochal cyst was classified into four groups: right angle (95.2 f 16.3 degrees), acute angle (38.6 f 14.4 degrees), complex, and normal (26.8 f 9.3 degrees) (presented here in the order of incidence). The right-angle type, that may correspond to type A [3], in which the common duct drains into the pancreatic duct, and the complex type tend to be observed in patients with cystic dilatation of the extrahepatic bile duct. In contrast, the acute-angle type seems to be found mainly in patients with cylindrical dilatation and corresponds to type B [3], in which the pancreatic duct drains into the choledochus. This angle is not as acute as those in patients with normal unions. Apparently normal junctions have rarely been seen in patients with cylindrical dilatation of the choledochus [5]. Moreover, intrahepatic ductal dilatation without choledochal dilatation has usually shown a normal junction of the pancreatobiliary system and, therefore, cannot be classified into the same category as choledochal cyst as has been reported previously [6,7]. A stenosis of the choledochus just above the pancreatobiliary junction seems to determine the type of choledochal cyst: high-grade stenosis causes cystic dilatation of the extrahepatic duct, and low-grade stenosis causes cylindrical dilatation. The length of the stenosis, however, is perhaps more telling of the type of choledochal cyst than the grade of stenosis. A long stenosis causes cystic dilatation and a short stenosis causes cylindrical dilatation. These findings are thought to result from inflammatory changes due to a reflux of pancreatic juice into the choledothus. The incidence of choledochal cysts with intrahepatic involvement is apparently much higher than previously thought, and cylindrical dilatation of the intrahepatic duct is observed much more often than cystic dilatation. However, cylindrical dilatation of the intrahepatic duct might have developed secondarily, because it tends to grow smaller after definitive surgery. Therefore, only cystic dilatation of the intrahepatic bile duct, which was observed in a quarter of the patients with choledochal cysts, might develop primarily. Patients with a right-angle junction are likely to complain of abdominal pain and to have an abdominal tumor or occasionally jaundice, whereas patients with an acute-angle junction, especially when accompanied with cylindrical ductal dilatation, seem to only suffer from abdominal pain. In addition, those with a complex union tend to have jaundice and an abdominal mass. Highly elevated amylase levels in the bile within the cyst are frequently observed. This fact lends support to the reflux theory of the pathogenesis of bile duct dilatation. Regurgitation of pancreatic juice into the choledochus causes abdominal pain and leads to degeneration of the epithelium of the bile duct, as has been revealed in experimental studies [B-10]. However, a normal amylase level is often 676
found in patients with a complex union and obstructive jaundice. This phenomenon suggests that obstruction of the junction prevents reflux of pancreatic juice into the choledochus. Summary An anomalous arrangement of the pancreatobiliary ductal system is usually observed in patients with a congenital choledochal cyst and is represented by a long common channel distal to the pancreatobiliary junction. According to the angle of the pancreatobiliary junction, anomalous junctions can be classified into four groups: right angle, acute angle, complex union, and normal union (presented here in the order of their incidence). The right-angle type tends to have cystic dilatation of the choledochus, whereas the acute-angle type generally has cylindrical dilatation. However, the grade and length of the &en&s on the distal part of the choledochus tend to determine the type of choledochal cyst. Cystic dilatation is usually observed in patients with high-grade and long stenosis, whereas cylindrical dilatation is seen in those with low-grade and short stenosis. Patients with an acute angle junction seem to only suffer from abdominal pain, and those in the complex, union group tend to have jaundice and an abdominal tumor. A high amylase level in the bile within the cyst is observed frequently. In patients with obstructive jaundice, however, the amylase level is usually not elevated, because pancreatic juice cannot enter the choledochus. References 1. Oi I, Hara T. Abnormal connection between the choledochus and ths pancreatic duct In case of congenital choledochal cyst examined by endoscopk panaeatocfwlangbqapity. Jpn J Pedlatr Surg 1977;9:1121-29 (in Japanese). 2. Koml N, Udaka H, lkeda N, Kashlwagi Y. Congenftaf difatatlon of the billary tracts: new classlficatton and study with particular reference to ancmalous arrangement of the pancreaticoblliary ducts. Gastroenterol Jpn 1977;12:293. 3. Babbitt DP. Choledochal cyst: new etiologlcal concept based on anomalws relationships of common bile duct and pancreatic bulb. Ann Radio1 1989:12:231-40. 4. Jona JZ, Babbitt DP, Starshak RJ. LaPorta AJ, Gllcklich M, Cohen D. Anatomic observattons md etbkqk and sugkaj considerations in choledochal cyst. J Pediatr Surg 1979; 14:315-20. 5. Matsumoto Y. Mashita Ft. Anomalous arrangement of the pancreatobiltary ductal system. Stomach and Intestine 1981;18:1209-12. (in Japanese). 8. Todani T, Watanabe Y, Narusue M, Tabuchi K. Dkajima K. Congenttal bile duct cysts. Am J Surg 1977;134:293-9. 7. Todani T, Narusue M, Watanabe Y, Tabuchi K, Ckajlma K. Mnagemsntofcongennalch&MocM cystwfthj~tic involvement. Ann Sure 1978; 187:272-80. 8. lkede N. Experimental a& cllnical studies on anomalous relatkmsh@ in the pancreatkobtlfary duct. Tokushima J Exp Msd 1978;25:47-57. 9. Myano T, Suugs K. Suds K. Abnumal chol~eatkzo ductal junction related to the etiology of infanttle obstnrctlve jaundice diseases. J Pediatr Surg 1979; 14: 16-26. 10. Dhkawa H, Sawaguchi S. Yamazaki Y. lsftikawa A, Klkuchi M. Experimental analysls of the ill effect of anomalcus pancreaticoblllary ductal union. J Pedlatr Surg 1982;17:7-13. The Amertcan Journrl of Surm