Gastroenterology and Hepatology Board Review: Pearls of Wisdom, Third Edition

Section VI GALLBLADDER, BILE DUCTS, AND PANCREAS

CHAPTER 31. Gallbladder, Bile Duct, and Pancreatic Congenital and Structural Abnormalities

Linda S. Lee, MD and Darwin L. Conwell, MD, MS

Image Define biliary atresia.

Obliteration of the intra- or extrahepatic bile ducts. There is some evidence to suggest that the ducts originally were present but were destroyed by an unknown process.

Image True/False: The gallbladder is usually also involved in extrahepatic biliary atresia.

True. Usually, only a fibrous remnant of the gallbladder and entire extrahepatic bile duct remains.

Image True/False: It is usually apparent at birth when biliary atresia is present.

False. It usually does not become evident until several weeks after birth.

Image How is biliary atresia diagnosed?

Hepatobiliary iminodiacetic acid (HIDA) scan which is 100% sensitive and 94% specific.

Image What is the treatment for biliary atresia and the success rate?

Kasai procedure (hepatic portoenterostomy) with one-third good long-term results, one-third requiring immediate liver transplantation, and one-third eventually needing transplantation due to progressive liver failure.

Image True/False: Regardless of an anomalous position of a gallbladder (eg, left-sided, intrahepatic, floating, etc), the cystic duct usually joins the common bile duct in a relatively normal position.

True. In general, the cystic duct joins the common hepatic duct in the usual position to form the common bile duct. The cystic duct may rarely join the right hepatic duct.

Image Define accessory and aberrant ducts.

Accessory ducts offer a second drainage route from the liver, whereas aberrant ducts are the only drainage routes for a specific region of the liver, but run along an unusual extrahepatic course rather than the normal intrahepatic route.

Image In which part of the liver are accessory and aberrant ducts usually found?

Accessory ducts are more common in the right side of the liver. Aberrant ducts almost exclusively drain the right anterior liver.

Image True/False: Choledochal cysts more commonly occur in men.

False. These cysts are about four times more common in women. There is also a higher incidence among Asians.

Image Describe the five types of choledochal cysts.

Image

Image Which type of choledochal cyst is most common?

Type I.

Image What are two theories of pathogenesis of choledochal cysts?

1) Pancreatic reflux and 2) distal common bile duct obstruction (presumably, failure of recanalization of the distal bile duct during intrauterine development leads to narrowing of the distal bile duct with proximal dilation).

Image What is anomalous pancreaticobiliary junction (APBJ)?

This congenital anomaly is defined as the junction of the common bile duct and pancreatic duct located outside the duodenal wall with a long common channel.

Image How often is APBJ associated with choledochal cysts?

70% of the time.

Image What is the significance of the presence of APBJ?

APBJ increases the risk of malignancy in the choledochal cyst when present and gallbladder in patients without biliary cysts.

Image What are potential risks of choledochal cysts if left unattended?

Severe cholangitis and adenocarcinoma (about 10%). Surgical excision is the usual treatment of these cysts, which may become massive in size.

Image True/False: A cholangiogram is useful to diagnose a choledochocele.

Image

Figure 31-1A, B

True.

Image How are symptomatic choledochoceles treated?

Image

Figure 31-1CD See also color plate.

Endoscopic sphincterotomy. Because the risk of malignant degeneration is very low, surgical resection is not required.

See Figure 31-1A for a magnetic resonance cholangiopancreatography (MRCP) of choledochocele. The arrow points to choledochocele. Figure 31-1B shows endoscopic retrograde cholangiopancreatography (ERCP) of choledochocele. The arrow points to choledochocele. See Figure 31-1C for an endoscopic view of choledochocele. Figure 31-1D shows choledochocele s/p sphincterotomy.

Image What is a Phrygian cap?

A congenital deformity of the gallbladder of no clinical significance whereby the fundus of the gallbladder is kinked.

Image Air in the gallbladder in the setting of acute cholecystitis suggests the development of what clinical entity?

Cholecystoenteric fistula due to necrosis of the gallbladder wall.

Image What gallstone-related syndrome produces obstruction via external compression of the common bile duct?

Image

Figure 31-2

In Mirizzi’s syndrome, a gallstone impacted in the cystic duct leads to compression and obstruction of the bile duct. See Figure 31-2A for cholangiogram of Mirizzi’s syndrome. The arrow points to a stone in cystic duct. Figure 31-2B shows cholangiogram of Mirizzi’s syndrome with stone extraction balloon sliding by stone in cystic duct.

Image What are the crescent-shaped folds of the cystic duct mucosa that may block passage of stones into the common bile duct?

Spiral valves of Heister.

Image What are the two main developmental abnormalities of morphology that account for most pancreatic congenital anomalies?

Abnormalities of rotation and fusion.

Image At about what week of gestation does the embryological development of the pancreas first appear?

About the fourth week of gestation, the pancreas first appears as two diverticula arising from the primitive foregut just distal to the stomach.

Image What are the names given to the pancreatic ducts that arise from the ventral and dorsal pancreatic buds?

The ventral duct joins with the dorsal duct to form the main pancreatic duct of Wirsung. The dorsal bud arises directly from the duodenal wall and undergoes varying degrees of atrophy to remain as the accessory duct of Santorini.

Image True/False: The pancreas lies within the peritoneal cavity.

False. The pancreas is a retroperitoneal organ.

Image What percentage of the population has normal pancreatic ductal anatomy?

Approximately 60%–70%.

Image True/False: Pancreas divisum is the most common congenital anomaly of the pancreas.

True.

Image What is the embryological cause of pancreas divisum?

Pancreas divisum results from incomplete fusion of the dorsal and ventral pancreatic ductal systems.

Image What percentage of autopsies is found to have pancreas divisum?

Pancreas divisum has been reported in up to 5%–10% in autopsy series. The prevalence may be even higher in patients undergoing ERCP for investigations of idiopathic pancreatitis.

Image What is the most common clinical presentation of patients with symptomatic pancreas divisum?

Most patients with pancreas divisum are asymptomatic with incidental detection of the anomaly. Those patients that are symptomatic have symptoms suggestive of acute pancreatitis that is thought to occur secondary to a combination of the anomaly and stenosis of the minor duodenal papilla.

Image At what age do patients with symptomatic pancreas divisum usually present?

The age of presentation varies widely but is most common between the third and forth decades of life.

Image What should be the initial therapeutic management of patients with symptomatic recurrent pancreatitis from pancreas divisum?

Although surgical minor papilla sphincteroplasty has traditionally been the treatment of choice, in experienced hands, endoscopic minor papilla dilation or sphincterotomy with temporary stenting has been shown to decrease the frequency of recurrent attacks of pancreatitis in pancreas divisum.

Image What test is most useful in diagnosing pancreas divisum?

Image

Figure 31-3

ERCP with injection of the main and minor pancreatic ducts demonstrates incomplete fusion of the dorsal and ventral pancreatic ductal systems. See Figure 31-3A for pancreatogram of complete pancreas divisum with injection into ventral pancreatic duct. Figure 31-3B shows pancreatogram of pancreas divisum with injection into the dorsal pancreatic duct.

Image What ectopic tissue is being demonstrated in the figure below?

Image

Figure 31-4 See also color plate.

A heterotopic pancreas also known as ectopic or aberrant pancreas (or pancreatic rest) is defined as the presence of pancreatic tissue that lacks anatomic and vascular continuity with the main body of the pancreas. Ectopic pancreas appears as a well-defined dome-shaped subepithelial nodule with central umbilication.

Image Where are the most common locations for ectopic pancreatic tissue?

Seventy percent of the ectopic pancreatic tissue is found in the upper gastrointestinal tract, including the stomach, duodenal, and jejunum. However, it has been seen in many other abdominal locations. The most common location is the preplyoric antrum along the greater curvature.

Image What is the most common presentation of patients with heterotopic pancreas?

Most cases of heterotopic pancreas are asymptomatic and the condition is generally discovered incidentally during the endoscopic evaluation of other gastrointestinal disorders.

Image What are the histologic findings on endoscopic biopsy of the nodule seen in heterotopic pancreas?

Endoscopic biopsy of the nodule yields only normal gastric mucosa because the pancreatic tissue is submucosal or subserosal in origin.

Image True/False: Any pathologic change in the normal pancreas such as malignancy, cyst formation, or islet cell tumors can occur in pancreatic rests.

True. While pancreatic rests are usually asymptomatic, symptoms may occur due to pathologic change of the ectopic pancreatic tissue and also due to the location of the pancreatic rest.

Image What treatment is recommended for heterotopic pancreatic tissue when discovered?

Incidental lesions should be left alone since long-term follow-up has not established a relationship between ectopic tissue and symptoms in most patients.

Image What is an annular pancreas?

An annular pancreas is a band of pancreatic tissue completely encircling the second portion of the duodenum.

Image What is the usual clinical presentation of annular pancreas in the pediatric and adult populations?

In the newborn, the lesion is associated with polyhydramnios and typically presents with inability to tolerate feedings. In adults, obstructive symptoms such as nausea and vomiting occur, particularly postprandially along with abdominal pain and bloating. Upper GI bleeding and duodenal ulcers occur in one-third of adults. Pancreatitis may also occur.

Image How is a diagnosis of annular pancreas established?

In neonates, a plain abdominal x-ray may reveal a classic “double-bubble,” which is diagnostic of duodenal obstruction. In adults and older children, plain x-ray films are unhelpful and other studies such as ERCP, magnetic resonance cholangiopancreatography, and/or abdominal CT scan are necessary to make the diagnosis.

Image What is the management of an annular pancreas?

In both newborns and adults, the management is surgical bypass of the obstructing lesion.

Image What congenital anomalies are associated with annular pancreas?

Duodenal atresia, Down’s syndrome, Meckel’s diverticulum, malrotation of intestine, intestinal webs, tracheoesophageal fistula, and imperforate anus.

Image What conditions are associated with multiple congenital cysts of the pancreas?

Multiple congenital cysts are associated with polycystic disease, cystic fibrosis, and Von Hippel–Lindau syndrome.

Image What is the management of a congenital cyst of the pancreas?

Surgical resection or drainage may be required for some patients with symptomatic solitary cysts; however, surgery is not usually necessary or advisable for patients with multiple cysts.

Image What is hypoplasia of the pancreas?

A congenital disease of the exocrine pancreas characterized by fatty replacement of acinar cells.

Image What is another name for hypoplasia of the pancreas?

Lipomatous pseudohypertrophy of the pancreas.

Image What is the usual clinical presentation of hypoplasia of the pancreas?

Severe pancreatic exocrine insufficiency

• • • SUGGESTED READINGS • • •

DiMagno MJ, Wamsteker EJ. Pancreas divisum. Curr Gastroenterol Rep. 2011;13:150-156.

Kamisawa T, Takuma K, Anjiki H, et al. Pancreaticobiliary maljunction. Clin Gastroenterol Hepatol. 2009;7:S84-S88.

Simeone DM, Mulholland MW. Pancreas: anatomy and structural anomalies. In: Yamada T, ed. Textbook of Gastronenterology. Philadelphia: Lippincott Williams & Wilkins; 2003:2013-2025.

Simeone DM. Gallbladder and biliary tract: anatomy and structural anomalies. In: Yamada T, ed. Textbook of Gastroneterology. Philadelphia: Lippincott Williams & Wilkins; 2003:2166-2176.