Which of the following is the most common presenting symptom in patients with a somatostatinoma?
Because somatostatin inhibits pancreatic and biliary secretions, patients with a somatostatinoma present with gallstones due to bile stasis, diabetes due to inhibition of insulin secretion, and steatorrhea due to inhibition of pancreatic exocrine secretion and bile secretion. Most somatostatinomas originate in the proximal pancreas or the pancreatoduodenal groove, with the ampulla and periampullary area as the most common site ( 60%). The most common presentations are abdominal pain (25%), jaundice (25%), and cholelithiasis (19%). This rare type of pancreatic endocrine tumor is diagnosed by confirming elevated serum somatostatin levels, which are usually above 10 ng/mL. Although most reported cases of somatostatinoma involve metastatic disease, an attempt at complete excision of the tumor and cholecystectomy is warranted in fit patients.
The etiology associated with chronic calcific pancreatitis is:
This type is the largest subgroup in the classification scheme proposed by Singer and Chari, and includes patients with calcific pancreatitis of most etiologies (Table below). Although the majority of patients with calcific pancreatitis have a history of alcohol abuse, stone formation and parenchymal calcification can develop in a variety of etiologic subgroups; hereditary pancreatitis and tropical pancreatitis are particularly noteworthy for the formation of stone disease. The clinician should therefore avoid the assumption that calcific pancreatitis confirms the diagnosis of alcohol abuse.
Classification of chronic pancreatitis based on etiologic causes:
In patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) for diagnosis and staging of chronic pancreatitis, the population most at risk of developing procedure-induced pancreatitis is:
Endoscopic retrograde cholangiopancreatography (ERCP) is considered to be the gold standard for the diagnosis and staging of chronic pancreatitis. It also serves as a vehicle that enables other diagnostic and therapeutic maneuvers, such as biopsy or brushing for cytology, or the use of stents to relieve obstruction or drain a pseudocyst (Fig. below). Unfortunately, ERCP also carries a risk of procedure-induced pancreatitis that occurs in approximately 5% of patients. Patients at increased risk include those with sphincter of Oddi dysfunction and those with a previous history of post-ERCP pancreatitis. Post-ERCP pancreatitis occurs after uncomplicated procedures, as well as after those that require prolonged manipulation. Severe pancreatitis and deaths have occurred after ERCP, it should be reserved for patients in whom the diagnosis is unclear despite the use of other imaging methods, or in whom a diagnostic or therapeutic maneuver is specifically indicated.
Pancreatic duct stenting. At endoscopic retrograde cholangiopancreatography, a stent is placed in the proximal pancreatic duct to relieve obstruction and reduce symptoms of pain. Pancreatic duct stents are left in place for only a limited time to avoid further inflammation.
Treatment of a 1-cm gastrinoma in the wall of the duodenum is best accomplished by:
Fifty percent of gastrinomas metastasize to lymph nodes or the liver, and are therefore considered malignant. Patients who meet criteria for operability should undergo exploration for possible removal of the tumor. Although the tumors are submucosal, a full-thickness excision of the duodenal wall is performed if a duodenal gastrinoma is found. All lymph nodes in Passaro triangle are excised for pathologic analysis. If the gastrinoma is found in the pancreas and does not involve the main pancreatic duct, it is enucleated. Pancreatic resection is justified for solitary gastrinomas with no metastases. A highly selective vagotomy can be performed if unresectable disease is identified or if the gastrinoma cannot be localized. This may reduce the amount of expensive proton pump inhibitors required. In cases in which hepatic metastases are identified, resection is justified if the primary gastrinoma is controlled and the metastases can be safely and completely removed. Debulking or incomplete removal of multiple hepatic metastases is probably not helpful, especially in the setting of MENl. The application of new modalities such as radiofrequency ablation seems reasonable, but data to support this approach are limited. Postoperatively, patients are followed with fasting serum gastrin levels, secretin stimulation tests, octreotide scans, and CT scans. In patients found to have inoperable disease, chemotherapy with streptozocin, doxorubicin, and 5-tluorouracil (5-FU) is used. Other approaches such as somatostatin analogues, interferon, and chemoembolization also have been used in gastrinoma with some success
The ERCP finding that is virtually diagnostic of intraductal papillary mucinous neoplasms (IPMNs) is:
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 (Fig. below). Imaging studies demonstrate diffuse dilation of the pancreatic duct, and the pancreatic parenchyma is often atrophic due to chronic duct obstruction. However, classic features of chronic pancreatitis, such as calcification and a beaded appearance of the duct, are not present. At ERCP, mucin can be seen extruding from the ampulla of Vater, a so-called fish-eye lesion, that is virtually diagnostic ofiPMN (Fig. below).
Intraductal papillary mucinous neoplasm histology. Papillary projections of ductal epithelium resemble villous morphology and contain mucin-filled vesicles.
Intraductal papillary mucinous neoplasm (IPMN). A. Examples of "fish-eye deformity" of IPMN. Mucin is seen extruding from the ampulla. B. Mucin coming from pancreatic duct when neck of pancreas is transected during Whipple procedure (left). Intraoperative pancreatic ductoscopy to assess the pancreatic tail (rig ht). C. Views of pancreatic duct during ductoscopy; normal (left) and IPMN (right).
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