Pancreas

Anatomy

100

A lack of communication between the main pancreatic duct and the accessory pancreatic duct is known as pancreatic divisum. This occurs how often: a. 10% b. 25% c. 50% d. 80%

a. 10% Anatomic configuration of the intrapancreatic ductal system. The classic anatomy is present in 60% of cases, where the accessory duct drains into the minor papilla and the main duct drains into the ampulla of Vater. The accessory pancreatic duct is blind and does not drain into the duodenum in 30% of cases. A lack of communication between the two ducts, which occurs in 10% of cases, is referred to as pancreas divisum. When this occurs, the main pancreatic duct drains into the duodenum through the minor papilla. Anatomic configuration of the intrapancreatic ductal system. The classic anatomy is present in 60% of cases, where the accessory duct drains into the minor papilla and the main duct drains into the ampulla of Vater. The accessory pancreatic duct is blind and does not drain into the duodenum in 30% of cases. A lack of communication between the two ducts, which occurs in 10% of cases, is referred to as pancreas divisum. When this occurs, the main pancreatic duct drains into the duodenum through the minor papilla.

200

The veins of the head of the pancreas drain into the a. Anterior surface of the portal vein b. Posterolateral surface of the portal vein c. Right renal vein d. Inferior vena cava

b. Posterolateral surface of the portal vein Venous branches draining the pancreatic head and uncinate process enter along the right lateral and posterior sides of the portal vein. There are usually no anterior venous tributaries, and a plane can usually be developed between the neck of the pancreas and the portal and superior mesenteric veins during pancreatic resection, unless the tumor is invading the vein anteriorly. (See Schwartz 9th ed., Chapter 33, Pancreas.)

300

During a Whipple procedure, division of the gastrodudenal artery is necessary to expose this vessel: a. superior mesenteric vein b. IVC c. superior mesenteric artery d. portal vein

d. portal vein

400

True or false: Annular pancreas is caused by malrotation of the dorsal pancreatic bud around the duodenum.

False Annular pancreas is a rare congenital anomaly of the pancreas first recognized in 1818. Early autopsy and surgical series estimate the incidence to be approximately 3 in 20,000.9,10 However, with better imaging modalities such as computed tomography (CT), magnetic resonance cholangiopancreatography (MRCP), and endoscopy, the incidence is thought to be closer to 1 in 1,000.11-13 People with annular pancreas have a thin band of normal pancreatic parenchyma completely surrounding the second portion of the duodenum. This band is in continuity with the head of the pancreas and causes variable degrees of duodenal compression and stenosis. In 1910, Lecco postulated that annular pancreas resulted from abnormal fusion of the ventral pancreatic bud to the duodenum, leading to improper rotation of the ventral bud around the duodenum.

500

Tumor invasion of all of the following structures indicates unresectability except: a. SMA b. root of small bowel mesentery c. common hepatic artery d. transverse colon

d. transverse colon

Physiology

100

Which of the following is the primary stimulus for secretion of bicarbonate by the pancreas? a. CCK b. Gastrin c. Acetylcholine d. Secretin

d. Secretin The hormone secretin is released from cells in the duodenal mucosa in response to acidic chyme passing through the pylorus into the duodenum. Secretin is the major stimulant for bicarbonate secretion, which buffers the acidic fluid entering the duodenum from the stomach. CCK also stimulates bicarbonate secretion, but to a much lesser extent than secretin. CCK potentiates secretin-stimulated bicarbonate secretion. Gastrin and acetylcholine, both stimulants of gastric acid secretion, are also weak stimulants of pancreatic bicarbonate secretion. (See Schwartz 9th ed., Chapter 33, Pancreas.)

200

Sympathetic stimulation of the pancreas results in a. Stimulation of endocrine and exocrine secretion b. Inhibition of endocrine and exocrine secretion c. Stimulation of endocrine and inhibition of exocrine secretion d. Inhibition of endocrine and stimulation of exocrine secretion

b. Inhibition of endocrine and exocrine secretion The pancreas is innervated by the sympathetic and parasympathetic nervous systems. The acinar cells responsible for exocrine secretion, the islet cells responsible for endocrine secretion, and the islet vasculature are innervated by both systems. The parasympathetic system stimulates endocrine and exocrine secretion and the sympathetic system inhibits secretion. (See Schwartz 9th ed., Chapter 33, Pancreas.)

300

True or false: Chloride secretion is directly proportional to bicarbonate secretion.

False Chloride efflux through the cystic fibrosis transmembrane conductance regulator (CFTR) leads to depolarization and bicarbonate entry through the sodium bicarbonate cotranporter.

400

True or false: Destruction of 50% of islet cells results in type-1 diabetes.

False 80%.

500

Mutations in which of the following lead to chronic pancreatitis? a. enterokinase b. trypsin c. SPINK1 d. CCK

c. SPINK1 Autodigestion of the pancreas by these proteolytic enzymes is prevented by packaging of proteases in an inactive precursor form and by the synthesis of protease inhibitors including pancreatic secretory trypsin inhibitor (PSTI), serine protease inhibitor kazal type 1 (SPINK1), and protease serine 1 (PRSS1). These enzymes are found in the acinar cell and loss of these protective mechanisms can lead to activation, autodigestion, and acute pancreatitis. Mutations in the SPINK1 and PRSS1 genes are known to cause one of the aggressive familial forms of chronic pancreatitis, leading to recurrent episodes of pancreatitis with associated exocrine and endocrine insufficiency.

Surgery

100

True or false: Splenic preserving distal pancreatectomy is an acceptable procedure for tail of the pancreas cancer.

False The spleen shares blood supply and lymphatic drainage with the tail of the pancreas and needs to be resected during a cancer operation.

200

During a whipple procedure, palpation of an arterial pulse posterior to the head of the pancreas is due to: a. aorta b. SMA c. replaced right hepatic artery d. splenic artery

c. replaced right hepatic artery Variations or anomalies in the pancreatic and biliary blood supply are found in 20% to 30% of people and mainly consist of portions of the hepatic arterial blood supply being replaced. In these cases, all or part of the hepatic arterial blood supply does not arise from the celiac axis. As much of the pancreatic blood supply is derived from the hepatic arterial blood supply, these variations lead to variations in the pancreatic blood supply. The most common anomaly is a replaced right hepatic artery arising from the superior mesenteric artery. This variation is seen in approximately 20% of patients. The replaced right hepatic artery arises from the proximal SMA in the retropancreatic position and traverses the upper edge of the uncinate process, then runs posterolateral to the portal vein. The right hepatic artery can also originate from the right gastric artery in 2% of cases or from the gastroduodenal artery in 6% of cases.

300

The procedure of choice for an insulinoma of the body of the pancreas is: a. enucleation b. central pancreatectomy c. distal pancreatectomy d. Whipple

a. enucleation Unlike most endocrine pancreatic tumors, the majority (90%) of insulinomas are benign and solitary, and only 10% are malignant. They are typically cured by simple enucleation. However, tumors located close to the main pancreatic duct and large (>2 cm) tumors may require a distal pancreatectomy or pancreaticoduodenectomy. Intraoperative US is useful to determine the tumor's relation to the main pancreatic duct and guides intraoperative decision making. Enucleation of solitary insulinomas and distal pancreatectomy for insulinoma can sometimes be performed using a minimally invasive technique.

400

Which of the following techniques decreases the risk for anastomotic leak after a Whipple procedure? a. end-to-side anastomosis b. side-to-side anastomosis c. duct to mucosa sutures d. none of the above

d. none of the above Techniques for the pancreaticojejunostomy include end-to-side or end-to-end and duct-to-mucosa sutures or invagination. Pancreaticogastrostomy has also been investigated. Some surgeons use stents, glue to seal the anastomosis, or octreotide to decrease pancreatic secretions. No matter what combination of these techniques is used, the pancreatic leakage rate is always about 10%. Therefore, the choice of techniques depends more on the surgeon's personal experience.

500

Patients with gallstone pancreatitis should undergo cholecystectomy a. Emergently (within the first 12-24 hours of admission) b. Within 48-72 hours of admission c. Following ERCP d. 4-6 weeks after resolution of symptoms

b. Within 48-72 hours of admission General consensus favors either urgent intervention (cholecystectomy) within the first 48 to 72 hours of admission, or briefly delayed intervention (after 72 hours, but during the initial hospitalization) to give an inflamed pancreas time to recover. Cholecystectomy and operative common duct clearance is probably the best treatment for otherwise healthy patients with obstructive pancreatitis. However, patients who are at high risk for surgical intervention are best treated by endoscopic sphincterotomy, with clearance of stones by ERCP. In the case of acute biliary pancreatitis in which chemical studies suggest that the obstruction persists after 24 hours of observation, emergency endoscopic sphincterotomy and stone extraction is indicated. Routine ERCP for examination of the bile duct is discouraged in cases of biliary pancreatitis, as the probability of finding residual stones is low, and the risk of ERCP-induced pancreatitis is significant. (See Schwartz 9th ed., Chapter 33, Pancreas.)

Benign

100

The most common endocrine tumor of the pancreas is a. Gastrinoma b. Glucagonoma c. Insulinoma d. Somatostatinoma

c. Insulinoma Insulinomas are the most common pancreatic endocrine neoplasms and present with a typical clinical syndrome known as Whipple's triad. The triad consists of symptomatic fasting hypoglycemia, a documented serum glucose level <50 mg/dL, and relief of symptoms with the administration of glucose. (See Schwartz 9th ed., Chapter 33, Pancreas.)

200

The most common location for a VIPoma is a. Head of the pancreas b. Tail of the pancreas c. Passaro's triangle d. Duodenal wall

b. Tail of the pancreas In 1958, Verner and Morrison first described the syndrome associated with a pancreatic neoplasm secreting VIP. The classic clinical syndrome associated with this pancreatic endocrine neoplasm consists of severe intermittent watery diarrhea leading to dehydration, and weakness from fluid and electrolyte losses. Large amounts of potassium are lost in the stool. The vasoactive intestinal peptidesecreting tumor (VIPoma) syndrome is also called the WDHA syndrome due to the presence of watery diarrhea, hypokalemia, and achlorhydria. The massive (5 L/d) and episodic nature of the diarrhea associated with the appropriate electrolyte abnormalities should raise suspicion of the diagnosis. Serum VIP levels must be measured on multiple occasions because the excess secretion of VIP is episodic, and single measurements might be normal and misleading. A CT scan localizes most VIPomas, although as with all islet cell tumors, EUS is the most sensitive imaging method. Electrolyte and fluid balance is sometimes difficult to correct preoperatively and must be pursued aggressively. Somatostatin analogues are helpful in controlling the diarrhea and allowing replacement of fluid and electrolytes. VIPomas are more commonly located in the distal pancreas and most have spread outside the pancreas.

300

The “fish eye” sign, or mucin extruding from the ampulla of Vater during ERCP, is virtually pathognomonic for a. Cystadenoma of the pancreas b. Mucinous cystadenoma c. Intraductal papillary mucinous neoplasm d. Mucinous adenocarcinoma of the pancreas

c. Intraductal papillary mucinous neoplasm At ERCP, mucin can be seen extruding from the ampulla of Vater, a so-called fish-eye lesion, that is virtually diagnostic of IPMN. Intraductal papillary mucinous neoplasms (IPMNs) usually occur within the head of the pancreas and arise within the pancreatic ducts. The ductal epithelium forms a papillary projection into the duct, and mucin production causes intraluminal cystic dilation of the pancreatic ducts. Patients are usually in their seventh to eighth decade of life and present with abdominal pain or recurrent pancreatitis, thought to be caused by obstruction of the pancreatic duct by thick mucin. Some patients (5 to 10%) have steatorrhea, diabetes, and weight loss secondary to pancreatic insufficiency.

400

Appropriate management of a patient with an asymptomatic 3-cm cystadenoma of the tail of the pancreas is a. Observation and serial CT scans b. Percutaneous cyst aspiration and sclerosis c. Enucleation d. Distal pancreatectomy

a. Observation and serial CT scans Serous cystadenomas are essentially considered benign tumors without malignant potential. Serous cystadenocarcinoma has been reported very rarely (<1%). Therefore, malignant potential should not be used as an argument for surgical resection, and the majority of these lesions can be safely observed in the absence of symptoms due to mass effect or rapid growth. All regions of the pancreas are affected, with half of cystadenomas found in the head/uncinate process, and half in the neck, body, or tail of the pancreas. They have a spongy appearance, and multiple small cysts (microcystic) are more common than larger cysts (macrocystic or oligocystic). These lesions contain thin serous fluid that does not stain positive for mucin and is low in CEA (<200 ng/mL). Typical imaging characteristics include a well-circumscribed cystic mass, small septations, fluid close to water density, and sometimes, a central scar with calcification. If a conservative management is adopted, it is important to be sure of the diagnosis. EUS-FNA should yield nonviscous fluid with low CEA and amylase levels, and if cells are obtained, which is rare, they are cuboidal and have a clear cytoplasm.

500

Which of the following is the most sensitive imaging study to identify and localize a gastrinoma? a. CT scan b. MRI c. PET scan d. Octreotide scintigraphy

d. Octreotide scintigraphy In 70 to 90% of patients, the primary gastrinoma is found in Passaro's triangle, an area defined by a triangle with points located at the junction of the cystic duct and common bile duct, the second and third portion of the duodenum, and the neck and body of the pancreas. However, because gastrinomas can be found almost anywhere, whole-body imaging is required. The test of choice is SSTR (octreotide) scintigraphy in combination with CT. The octreotide scan is more sensitive than CT, locating about 85% of gastrinomas and detecting tumors <1 cm. With the octreotide scan, the need for tedious and technically demanding selective angiography and measurement of gastrin gradients has declined. EUS is another new modality that assists in the preoperative localization of gastrinomas. It is particularly helpful in localizing tumors in the pancreatic head or duodenal wall, where gastrinomas are usually <1 cm in size. A combination of octreotide scan and EUS detects >90% of gastrinomas. (See Schwartz 9th ed., Chapter 33, Pancreas.)

Malignant

100

Which of the following is NOT a risk factor for pancreatic cancer? a. Age >60 b. African American race c. Smoking d. Female gender

d. Female gender Pancreatic cancer is more common in the elderly with most patients being >60 years old. Pancreatic cancer is more common in African Americans and slightly more common in men than women. The risk of developing pancreatic cancer is two to three times higher if a parent or sibling had the disease. Another risk factor that is consistently linked to pancreatic cancer is cigarette smoking. Smoking increases the risk of developing pancreatic cancer by at least twofold due to the carcinogens in cigarette smoke. Coffee and alcohol consumption have been investigated as possible risk factors, but the data are inconsistent. As in other GI cancers, diets high in fat and low in fiber, fruits, and vegetables are thought to be associated with an increased risk of pancreatic cancer.

200

Which of the following is NOT an indication for diagnostic laparoscopy to determine respectability in a patient with pancreatic cancer? a. CT demonstrates respectable disease b. CA19-9 is high c. Tumor size <2 cm d. Ascites

c. Tumor size <2 cm Diagnostic laparoscopy is possibly best applied to patients with pancreatic cancer on a selective basis. Diagnostic laparoscopy will have a higher yield in patients with large tumors (>4 cm), tumors located in the body or tail, patients with equivocal findings of metastasis or CT scan, ascites, high CA 19-9, or marked weight loss. (See Schwartz 9th ed, Chapter 33, Pancreas and Fig. 33–5.)

300

At the time of laparotomy, which of the following is a contraindication to proceeding with a Whipple resection? a. Duodenal invasion b. Pyloric invasion c. Clinically positive hilar lymph nodes d. Clinically positive peripancreatic nodes

c. Clinically positive hilar lymph nodes Hepatic hilar node involvement is a contraindication to proceeding with the Whipple procedure. Enlarged or firm lymph nodes that can be swept down toward the head of the pancreas with the specimen do not preclude resection. Invasion of the duodenum or pylorus is not a contraindication to resection. (See Schwartz 9th ed., Chapter 33, Pancreas.)

400

The median survival following pancreaticoduodenectomy (Whipple procedure) for pancreatic cancer is approximately a. 10 months b. 2 years c. 4 years d. 8 years

b. 2 years Median survival after pancreaticoduodenectomy is about 22 months. Even long-term (5-year) survivors often eventually die due to pancreatic cancer recurrence. Although pancreaticoduodenectomy may be performed with the hope of the rare cure in mind, the operation more importantly provides better palliation than any other treatment, and is the only modality that offers any meaningful improvement in survival. If the procedure is performed without major complications, many months of palliation are usually achieved. It is the surgeon's duty to make sure patients and their families have a realistic understanding of the true goals of pancreaticoduodenectomy in the setting of pancreatic cancer. (See Schwartz 9th ed., Chapter 33, Pancreas.)

500

Which of the following is suggestive of malignancy in a cystic lesion of the pancreas? a. Elevated LDH in the cyst fluid b. Cyst wall >3 mm in thickness c. Thick, mucinous fluid in the cyst cavity d. Hemorrhagic fluid in the cyst cavity

c. Thick, mucinous fluid in the cyst cavity A cystic neoplasm needs to be considered when a patient presents with a fluid-containing pancreatic lesion. Cystic neoplasms of the pancreas may be more frequent than previously recognized and are being identified with increasing frequency as the use of abdominal CT scanning has increased. Most of these lesions are benign or slow growing, and the prognosis is significantly better than with pancreatic adenocarcinoma. However, some of these neoplasms slowly undergo malignant transformation and thus represent an opportunity for surgical cure, which is exceedingly uncommon in the setting of pancreatic adenocarcinoma. Cysts that contain thick fluid with mucin, elevated carcinoembryonic antigen (CEA), or atypical cells must be treated as potentially malignant (Fig. 33–4). (See Schwartz 9th ed., Chapter 33, Pancreas.)