Is Choledochocele Innocent Bystander or Culprit? Reply to Kim et al.

Dear Sir,

The most important finding in our study is the high amylase level in bile demonstrated in patients with choledochocele. It is well known that pancreaticobiliary malunion (PBM) is a risk factor for the development of carcinoma in the biliary tract, and carcinomas tend to occur where the bile containing amylase stagnates: i. e. common bile duct carcinoma in those with a choledochal cyst and gallbladder carcinoma where there is no cyst [1] [2]. Changes in biliary phospholipids as a result of reflux of pancreatic juice into the biliary tract via the PBM may be responsible for the malignant change [3]. Choledochocele often causes acute cholangitis and/or pancreatitis, which are considered to be due to bile stagnation in the choledochocele itself [4]. This is likely to be true because endoscopic sphincterotomy (ES) is usually effective in relieving symptoms [5] [6]. Although choledochocele is excluded from the category of PBM, all of our four patients examined showed a high amylase concentration in bile. From this point of view, if the carcinoma had an association with choledochocele, it would tend to occur in the choledochocele itself. As Kim et al. state, it is very difficult to determine the precise origin of carcinoma in some cases, but two patients, one described in the report of Ozawa et al. [7] and one in our series, were considered to have a carcinoma in a choledochocele. The description suggested by Kim et al., i. e. ”Carcinoma associated with choledochocele,“ sounds vague as to whether the carcinoma is primary or secondary. The analysis of bile in our study presents the possibility that carcinoma may develop secondarily in the choledochocele by the same mechanism as carcinogenesis in patients with PBM, and thus we gave our article the title ”Carcinoma arising in choledochocele.“ How are Kim et al. able to state that the choledochocele of their patient was secondary? Is this mere coincidence?

In contrast to the other types of choledochal cyst, choledochocele tends to occur in older patients, the mean age in this study being 68 years. Pancreatoduodenectomy is a curative treatment for periampullary carcinoma, but it is too invasive as a prophylactic procedure. With the recent development of endoscopic techniques, it has become easy to examine the periampullary region completely and repeatedly. Endoscopic papillectomy has also been reported to be effective [8]. Thus, we consider that ES is adequate as the first-step treatment for choledochocele, if malignancy has been ruled out. However, meticulous follow-up is necessary for early detection of development of malignancy, as described in our article.

There remains much controversy about the origin and prognosis of choledochocele, and further investigations from various perspectives are necessary to better understand this rare condition.

References

• 1 Todani T, Tabuchi K, Watanabe Y. et al . Carcinoma arising in the wall of congenital bile duct cysts.  Cancer. 1979;  44 1134-1141
• 2 Kimura K, Ohto M, Saisho H. et al . Association of gallbladder carcinoma and anomalous pancreaticobiliary ductal union.  Gastroenterology. 1985;  89 1258-1265
• 3 Shimada K, Yanagisawa J, Nakayama F. Increased lysophosphatidylcholine and pancreatic enzyme content in bile of patients with anomalous pancreaticobiliary ductal junction.  Hepatology. 1991;  13 438-444
• 4 Goldberg P B, Long W B, Oleaga L A, Mackie J A. Choledochocele as a cause of recurrent pancreatitis.  Gastroenterology. 1980;  78 1041-1045
• 5 Gerritsen J J, Janssens A R, Kroon H M. Choledochocele: treatment by endoscopic sphincterotomy.  Br J Surg. 1988;  75 495-496
• 6 Martin R F, Biber B P, Bosco J J, Howell D A. Symptomatic choledochoceles in adults. Endoscopic retrograde cholangiopancreatography recognition and management.  Arch Surg. 1992;  127 536-539
• 7 Ozawa K, Yamada T, Matsumoto Y, Tobe R. Carcinoma arising in a choledochocele.  Cancer. 1980;  45 195-197
• 8 Chatila R, Andersen D K, Topazian M. Endoscopic resection of a choledochocele.  Gastrointest Endosc. 1999;  50 578-580