WDHA Syndrome Medication
- Author: Sandeep Mukherjee, MB, BCh, MPH, FRCPC; Chief Editor: Julian Katz, MD more...
Medication Summary
Medications used to treat WDHA syndrome are divided into 2 categories: (1) antisecretory agents (eg, somatostatin and its synthetic derivatives) to treat secretory diarrhea and (2) chemotherapeutic agents. Conventional antidiarrheals are useful adjuncts to somatostatin analogs.
Preliminary data suggest that octreotide administered postoperatively is associated with a lower rate of complications, such as the development of pancreatic fistula. As a result, many surgical units routinely administer octreotide until the abdominal drains have been removed and the patient is eating normally.
Histamine 2 (H2)–receptor antagonists or proton pump inhibitors should be administered postoperatively to prevent hyperacidity, because rebound hyperchlorhydria is common in the postoperative period.
Surgery, however, is the only curative therapy. Neither somatostatin nor interferon alfa has significant tumoricidal properties, although they may have a tumorostatic effect.
Somatostatin Analogs
Class Summary
Antisecretory agents are used to treat the profuse secretory diarrhea of WDHA syndrome after patients have been resuscitated adequately. Although conventional antidiarrheals may play an adjunctive role, somatostatin derivatives are the most effective and cost-saving drugs for treating diarrhea in this disease.
Because VIPomas possess somatostatin receptors, somatostatin and its synthetic derivatives are used not only for tumor imaging but also to inhibit hormonal secretion of functional tumors. Radioactively labeled somatostatin derivatives currently are being investigated in the treatment of these tumors.
Octreotide (Sandostatin, Sandostatin LAR)
Octreotide is a synthetic analog of somatostatin with a half-life of approximately 100 minutes.
It is a potent physiologic inhibitor of numerous gastrointestinal (GI) functions, including the following:
- Release of GI peptides - Eg, cholecystokinin (CCK), gastrin, and secretin
- Gastric acid secretion
- Intestinal blood flow
- Gall bladder and intestinal motility
- Pancreatic enzyme secretion
- Mucosal secretion in the small intestine
These inhibitory effects, either alone or in combination, contribute to the antidiarrheal effect. Antisecretory agents improve diarrhea in as many as 86% of patients with WDHA syndrome and have been reported to decrease tumor size in up to 16% patients.
Octreotide may stabilize tumor growth in some patients but has only minimal tumoricidal activity. Some patients with troublesome diarrhea experience reduced responsiveness to octreotide with time, and, although the VIP levels decline, they do not return to baseline values. Two possible reasons for such tachyphylaxis are accelerated octreotide degradation and down-regulation of somatostatin receptors. Regardless of the mechanism, rebound diarrhea can be difficult to treat.
Sandostatin LAR is a long-acting somatostatin analog that is currently not available in the United States.
Lanreotide (Somatuline LA)
Lanreotide is a somatostatin octapeptide analog with a considerably longer half-life than octreotide. It inhibits multiple endocrine, exocrine, and neuroendocrine mechanisms. Lanreotide reduces insulinlike growth factor-1 and growth hormone secretion.
Antineoplastics, Other
Class Summary
Chemotherapeutic agents are used to treat metastatic WDHA syndrome when surgical resection is not possible. The combination of streptozotocin and doxorubicin is superior to streptozotocin and 5-FU in the treatment of advanced islet cell carcinoma. Chlorozotocin alone is similar in efficacy to streptozotocin plus 5-FU but has fewer adverse effects than streptozotocin-containing regimens.
Streptozotocin (Zanosar)
Streptozotocin is a naturally occurring nitrosourea that was originally discovered as an antibiotic obtained from Streptomyces achromogenes. It is capable of inhibiting deoxyribonucleic acid (DNA) synthesis during all stages of the mammalian cycle through liberation of alkylating and carbamoylating moieties.
Streptozotocin has a methylnitrosourea (MNU) moiety attached to 2 carbon of glucose and has a special affinity for islet of Langerhans cells. It has a half-life of approximately 15 minutes; only 10-20% of the dose is recovered in urine.
Chlorozotocin (DCNU, Dome, NSC 178248)
Chlorozotocin is not available in the United States. It is an antineoplastic nitrosourea in which the 2 carbon of glucose is substituted with the chloronitrosourea group (CNU).
Doxorubicin (Adriamycin)
Doxorubicin is an anthracycline antibiotic derived from the fungus S peucetius var caesius. It intercalates with DNA and disrupts many functions, including DNA and RNA synthesis. Its maximum toxicity occurs during S phase of the cell cycle.
Doxorubicin has a multiphasic disappearance curve, with half-lives ranging up to 30 hours. It does not cross the blood-brain barrier but is taken up rapidly by the heart, lungs, liver, kidneys, and spleen.
Fluorouracil (Adrucil)
Fluorouracil is a pyrimidine analog of uracil, which inhibits RNA function and thymidylate synthesis. Fluorouracil requires enzymatic conversion to a nucleotide to exert cytotoxic activity. Interruption of thymidylate synthesis results in inhibition of DNA synthesis while RNA and protein production continues. This causes an imbalance in growth that is not compatible with cell survival.
Fluorouracil is administered parenterally and is metabolized primarily in the liver. It is inactivated by reduction of the pyrimidine ring by dihydrouracil dehydrogenase. Because this enzyme is widely distributed in body, dose modification of fluorouracil is not required in the presence of liver disease. Fluorouracil readily enters the cerebrospinal fluid (CSF), with values that slowly subside over 9 hours. Urinary excretion of a single intravenous (IV) dose is only 11% in 24 hours.
Immunomodulators
Class Summary
Interferons are glycoproteins with a variety of biologic actions. They are important cytokines that have immunomodulating, antiviral, and antiproliferative properties. Interferons alfa and beta are produced by most cells in response to viral infections, while interferon gamma is produced only by T lymphocytes.
Interferon alfa-2b (Intron A)
Interferon alfa is a highly purified protein containing 165 amino acid residues. Interferons must be administered subcutaneously or intramuscularly. Interferon alfa is rapidly inactivated in body fluids and various tissues, with an initial half-life of 40 minutes and a terminal half-life of 5 hours. Negligible amounts are excreted renally. Interferon has been used as monotherapy and in combination with octreotide.
Antidiarrheals
Class Summary
These agents are often used with somatostatin analogs. Although a wide variety of these medications has been tried, the most commonly used antidiarrheal is loperamide (Imodium).
Loperamide (Imodium, Diamode)
Loperamide is a synthetic piperidine derivative that slows intestinal transit by direct effect on nerve endings and intestinal wall ganglia. It interferes with cholinergic and noncholinergic mechanisms involved in peristalsis, resulting in reduced activity of the intestinal wall muscles. Like diphenoxylate and morphine, it may enhance contractions of intestinal circular muscles, thus increasing segmentation and retarding intestinal forward motion.
Loperamide is more specific, longer-acting, and 3 times more potent than diphenoxylate on a weight basis. Neither tolerance to the antidiarrheal effect of loperamide nor physical dependence on the drug has been reported.
The apparent elimination half-life of loperamide in healthy adults is 9-14 hours. Less than 2% of the drug is excreted in urine; 30% is excreted as an intact molecule in feces. Enterohepatic circulation has been described in animals. Whether loperamide crosses the placenta or is distributed in milk is unknown.
Histamine H2 Antagonists
Class Summary
H2 blockers are reversible competitive blockers of histamine at H2 receptors, particularly those in the gastric parietal cells (where they inhibit acid secretion). The H2 antagonists are highly selective, they do not affect the H1 receptors, and they are not anticholinergic agents.
Histamine 2 (H2)–receptor antagonists or proton pump inhibitors should be administered postoperatively to prevent hyperacidity, because rebound hyperchlorhydria is common in the postoperative period.
Ranitidine (Zantac)
This agent inhibits histamine stimulation of H2 receptors in gastric parietal cells, which reduces gastric acid secretion, gastric volume, and hydrogen ion concentrations.
Famotidine (Pepcid)
Famotidine competitively inhibits histamine at the H2 receptors in gastric parietal cells, reducing gastric acid secretion, gastric volume, and hydrogen concentrations.
Nizatidine (Axid, Axid AR)
This agent competitively inhibits histamine at the H2 receptor of the gastric parietal cells, resulting in reduced gastric acid secretion, gastric volume, and hydrogen concentrations.
Cimetidine (Tagamet HB 200)
This agent inhibits histamine at H2 receptors of gastric parietal cells, which results in reduced gastric acid secretion, gastric volume, and hydrogen concentrations.
Proton Pump Inhibitors
Class Summary
PPIs inhibit gastric acid secretion by inhibition of the H+/K+/ATPase enzyme system in the gastric parietal cells. IV therapy may be a useful adjunct via stabilization of the clot by increasing intragastric pH.
H2-receptor antagonists or proton pump inhibitors should be administered postoperatively to prevent hyperacidity, because rebound hyperchlorhydria is common in the postoperative period.
Lansoprazole (Prevacid)
Lansoprazole is a substituted benzimidazole that covalently and irreversibly binds the hydrogen potassium/ATPase, thereby inhibiting acid secretion. This agent is available as an IV formulation, oral (PO) capsule, or SoluTab. Strawberry-flavored SoluTabs can be dissolved in water for easy administration to children. Dissolve the 15-mg SoluTab in 4 mL of water and the 30-mg SoluTab in 10 mL of water.
Omeprazole (Prilosec)
Omeprazole is a substituted benzimidazole that suppresses acid secretion by specific inhibition of hydrogen potassium/ATPase at the secretory surface of the parietal cell.
Pantoprazole (Protonix)
Pantoprazole is a substituted benzimidazole that suppresses acid secretion by specific inhibition of hydrogen potassium/ATPase at the secretory surface of the parietal cell.
Esomeprazole magnesium (Nexium)
This agent suppresses gastric acid secretion by specifically inhibiting the H+/K+/ATPase enzyme system at the secretory surface of gastric parietal cells.
Priest WM, Alexander MK. Isletcell tumour of the pancreas with peptic ulceration, diarrhoea, and hypokalaemia. Lancet. Dec 7 1957;273(7006):1145-7. [Medline].
Verner JV, Morrison AB. Islet cell tumor and a syndrome of refractory watery diarrhea and hypokalemia. Am J Med. Sep 1958;25(3):374-80. [Medline].
Matsumoto KK, Peter JB, Raymond G. Watery diarrhea and hypokalemia associated with pancreatic islet cell adenoma. Gastroenterology. 1966;50:231-42.
Tannapfel A, Vomschloss S, Karhoff D, Markwarth A, Hengge UR, Wittekind C, et al. BRAF gene mutations are rare events in gastroenteropancreatic neuroendocrine tumors. Am J Clin Pathol. Feb 2005;123(2):256-60. [Medline].
Virgolini I, Kurtaran A, Leimer M, Kaserer K, Peck-Radosavljevic M, Angelberger P, et al. Location of a VIPoma by iodine-123-vasoactive intestinal peptide scintigraphy. J Nucl Med. Sep 1998;39(9):1575-9. [Medline].
Case CC, Wirfel K, Vassilopoulou-Sellin R. Vasoactive intestinal polypeptide-secreting tumor (VIPoma) with liver metastases: dramatic and durable symptomatic benefit from hepatic artery embolization, a case report. Med Oncol. 2002;19(3):181-7. [Medline].
Soga J, Yakuwa Y. Vipoma/diarrheogenic syndrome: a statistical evaluation of 241 reported cases. J Exp Clin Cancer Res. Dec 1998;17(4):389-400. [Medline].
Akerström G, Hellman P. Surgery on neuroendocrine tumours. Best Pract Res Clin Endocrinol Metab. Mar 2007;21(1):87-109. [Medline].
Alexakis N, Neoptolemos JP. Pancreatic neuroendocrine tumours. Best Pract Res Clin Gastroenterol. 2008;22(1):183-205. [Medline].
Ayub A, Zafar M, Abdulkareem A, Ali MA, Lingawi T, Harbi A. Primary hepatic vipoma. Am J Gastroenterol. Jun 1993;88(6):958-61. [Medline].
Bartsch D, Hahn SA, Danichevski KD, Ramaswamy A, Bastian D, Galehdari H, et al. Mutations of the DPC4/Smad4 gene in neuroendocrine pancreatic tumors. Oncogene. Apr 8 1999;18(14):2367-71. [Medline].
Bartsch DK, Fendrich V, Langer P, Celik I, Kann PH, Rothmund M. Outcome of duodenopancreatic resections in patients with multiple endocrine neoplasia type 1. Ann Surg. Dec 2005;242(6):757-64, discussion 764-6. [Medline].
Berkovic MC, Altabas V, Herman D, Hrabar D, Goldoni V, Vizner B, et al. A single-centre experience with octreotide in the treatment of different hypersecretory syndromes in patients with functional gastroenteropancreatic neuroendocrine tumors. Coll Antropol. Jun 2007;31(2):531-4. [Medline].
Bettini R, Boninsegna L, Mantovani W, Capelli P, Bassi C, Pederzoli P, et al. Prognostic factors at diagnosis and value of WHO classification in a mono-institutional series of 180 non-functioning pancreatic endocrine tumours. Ann Oncol. May 2008;19(5):903-8. [Medline].
Bramley PN, Lodge JP, Losowsky MS, Giles GR. Treatment of metastatic Vipoma by liver transplantation. Clin Transplant. Oct 1990;4(5 part 1):276-8; discussion 279. [Medline].
Brunt LM, Mazoujian G, O'Dorisio TM, Wells SA Jr. Stimulation of vasoactive intestinal peptide and neurotensin secretion by pentagastrin in a patient with VIPoma syndrome. Surgery. Mar 1994;115(3):362-9. [Medline].
Buchanan KD, Johnston CF, O'Hare MM, Ardill JE, Shaw C, Collins JS, et al. Neuroendocrine tumors. A European view. Am J Med. Dec 22 1986;81(6B):14-22. [Medline].
Crowley PF, Slavin JL, Rode J. Massive amyloid deposition in pancreatic vipoma: a case report. Pathology. Nov 1996;28(4):377-9. [Medline].
Doherty GM. Multiple endocrine neoplasia type 1. J Surg Oncol. Mar 1 2005;89(3):143-50. [Medline].
Doherty GM. Rare endocrine tumours of the GI tract. Best Pract Res Clin Gastroenterol. Oct 2005;19(5):807-17. [Medline].
Eriksson B, Oberg K. Interferon therapy of malignant endocrine pancreatic tumors. In: Mignon M, Jensen RT, eds. Endocrine Tumors of the Pancreas: Recent Advances in Research and Management. Series: Frontiers in Gastrointestinal Research. Vol 23. Basel, Switzerland: S. Karger; 1995:451-60.
Fendrich V, Habbe N, Celik I, Langer P, Zielke A, Bartsch DK, et al. [Operative management and long-term survival in patients with neuroendocrine tumors of the pancreas--experience with 144 patients]. Dtsch Med Wochenschr. Feb 2 2007;132(5):195-200. [Medline].
Frank M, Klose KJ, Wied M, Ishaque N, Schade-Brittinger C, Arnold R. Combination therapy with octreotide and alpha-interferon: effect on tumor growth in metastatic endocrine gastroenteropancreatic tumors. Am J Gastroenterol. May 1999;94(5):1381-7. [Medline].
Ghaferi AA, Chojnacki KA, Long WD, Cameron JL, Yeo CJ. Pancreatic VIPomas: subject review and one institutional experience. J Gastrointest Surg. Feb 2008;12(2):382-93. [Medline].
Gibril F, Reynolds JC, Chen CC, Yu F, Goebel SU, Serrano J, et al. Specificity of somatostatin receptor scintigraphy: a prospective study and effects of false-positive localizations on management in patients with gastrinomas. J Nucl Med. Apr 1999;40(4):539-53. [Medline].
Goh BK, Ooi LL, Tan YM, Cheow PC, Chung YF, Chow PK. Clinico-pathological features of cystic pancreatic endocrine neoplasms and a comparison with their solid counterparts. Eur J Surg Oncol. Jun 2006;32(5):553-6. [Medline].
Gumbs AA, Grès P, Madureira F, Gayet B. Laparoscopic vs open resection of pancreatic endocrine neoplasms: single institution's experience over 14 years. Langenbecks Arch Surg. May 2008;393(3):391-5. [Medline].
Görtz B, Roth J, Krahenmann A, de Krijger RR, Muletta-Feurer S, Rütimann K, et al. Mutations and allelic deletions of the MEN1 gene are associated with a subset of sporadic endocrine pancreatic and neuroendocrine tumors and not restricted to foregut neoplasms. Am J Pathol. Feb 1999;154(2):429-36. [Medline].
Harris AG, O'Dorisio TM, Woltering EA, Anthony LB, Burton FR, Geller RB, et al. Consensus statement: octreotide dose titration in secretory diarrhea. Diarrhea Management Consensus Development Panel. Dig Dis Sci. Jul 1995;40(7):1464-73. [Medline].
Ichimura T, Kondo S, Okushiba S, Morikawa T, Katoh H. A calcitonin and vasoactive intestinal peptide-producing pancreatic endocrine tumor associated with the WDHA syndrome. Int J Gastrointest Cancer. 2003;33(2-3):99-102. [Medline].
Ikuta S, Yasui C, Kawanaka M, Aihara T, Yoshie H, Yanagi H, et al. Watery diarrhea, hypokalemia and achlorhydria syndrome due to an adrenal pheochromocytoma. World J Gastroenterol. Sep 14 2007;13(34):4649-52. [Medline].
Jackson C, Buchman AL. Calcitonin-secreting VIPoma. Dig Dis Sci. Dec 2005;50(12):2203-6. [Medline].
Kazanjian KK, Reber HA, Hines OJ. Resection of pancreatic neuroendocrine tumors: results of 70 cases. Arch Surg. Aug 2006;141(8):765-9; discussion 769-70. [Medline].
Keller J, Mueller-Wolf JC, Ahmadi-Simab K, Fibbe C, Rosien U, Layer P. Do elevated plasma vasoactive intestinal polypeptide (VIP) levels cause small intestinal motor disturbances in humans?. Dig Dis Sci. Feb 2005;50(2):276-82. [Medline].
Krejs GJ. Comparison of the effect of VIP and PHI on water and ion movement in the canine jejunum in vivo. Gastroenterol Clin Biol. 1984;8:868.
Levy-Bohbot N, Merle C, Goudet P, Delemer B, Calender A, Jolly D, et al. Prevalence, characteristics and prognosis of MEN 1-associated glucagonomas, VIPomas, and somatostatinomas: study from the GTE (Groupe des Tumeurs Endocrines) registry. Gastroenterol Clin Biol. Nov 2004;28(11):1075-81. [Medline].
Lubinski SM, Hendrix T. Images in clinical medicine. VIPoma. N Engl J Med. Aug 19 2004;351(8):808. [Medline].
Lévy-Bohbot N, Merle C, Goudet P, Delemer B, Calender A, Jolly D, et al. Prevalence, characteristics and prognosis of MEN 1-associated glucagonomas, VIPomas, and somatostatinomas: study from the GTE (Groupe des Tumeurs Endocrines) registry. Gastroenterol Clin Biol. Nov 2004;28(11):1075-81. [Medline].
Mansour JC, Chen H. Pancreatic endocrine tumors. J Surg Res. Jul 2004;120(1):139-61. [Medline].
Mao C, Carter P, Schaefer P, Zhu L, Dominguez JM, Hanson DJ, et al. Malignant islet cell tumor associated with hypercalcemia. Surgery. Jan 1995;117(1):37-40. [Medline].
Maton PN, Gardner JD, Jensen RT. Use of long-acting somatostatin analog SMS 201-995 in patients with pancreatic islet cell tumors. Dig Dis Sci. Mar 1989;34(3 Suppl):28S-39S. [Medline].
Moertel CG, Lefkopoulo M, Lipsitz S, Hahn RG, Klaassen D. Streptozocin-doxorubicin, streptozocin-fluorouracil or chlorozotocin in the treatment of advanced islet-cell carcinoma. N Engl J Med. Feb 20 1992;326(8):519-23. [Medline].
Moug SJ, Leen E, Horgan PG, Imrie CW. Radiofrequency ablation has a valuable therapeutic role in metastatic VIPoma. Pancreatology. 2006;6(1-2):155-9. [Medline].
Murphy MS, Sibal A, Mann JR. Persistent diarrhoea and occult vipomas in children. BMJ. Jun 3 2000;320(7248):1524-6. [Medline].
Nguyen HN, Backes B, Lammert F, Wildberger J, Winograd R, Busch N, et al. Long-term survival after diagnosis of hepatic metastatic VIPoma: report of two cases with disparate courses and review of therapeutic options. Dig Dis Sci. Jun 1999;44(6):1148-55. [Medline].
Nikou GC, Toubanakis C, Nikolaou P, Giannatou E, Safioleas M, Mallas E. VIPomas: an update in diagnosis and management in a series of 11 patients. Hepatogastroenterology. Jul-Aug 2005;52(64):1259-65. [Medline].
Nobels FR, Kwekkeboom DJ, Bouillon R, Lamberts SW. Chromogranin A: its clinical value as marker of neuroendocrine tumours. Eur J Clin Invest. Jun 1998;28(6):431-40. [Medline].
Oberg K, Eriksson B. Endocrine tumours of the pancreas. Best Pract Res Clin Gastroenterol. Oct 2005;19(5):753-81. [Medline].
Onozawa M, Fukuhara T, Minoguchi M, Takahata M, Yamamoto Y, Miyake T. Hypokalemic rhabdomyolysis due to WDHA syndrome caused by VIP-producing composite pheochromocytoma: a case in neurofibromatosis type 1. Jpn J Clin Oncol. Sep 2005;35(9):559-63. [Medline].
Orlefors H, Sundin A, Ahlstrom H, Bjurling P, Bergstrom M, Lilja A, et al. Positron emission tomography with 5-hydroxytryprophan in neuroendocrine tumors. J Clin Oncol. Jul 1998;16(7):2534-41. [Medline].
Park SK, O'Dorisio MS, O'Dorisio TM. Vasoactive intestinal polypeptide-secreting tumours: biology and therapy. Baillieres Clin Gastroenterol. Dec 1996;10(4):673-96. [Medline].
Pederzoli P, Bassi C, Falconi M, Camboni MG. Efficacy of octreotide in the prevention of complications of elective pancreatic surgery. Italian Study Group. Br J Surg. Feb 1994;81(2):265-9. [Medline].
Phan GQ, Yeo CJ, Hruban RH, Lillemoe KD, Pitt HA, Cameron JL. Surgical experience with pancreatic and peripancreatic neuroendocrine tumors: review of 125 patients. J Gastrointest Surg. Sep-Oct 1998;2(5):472-82. [Medline].
Pratz KW, Ma C, Aubry MC, Vrtiska TJ, Erlichman C. Large cell carcinoma with calcitonin and vasoactive intestinal polypeptide-associated Verner-Morrison syndrome. Mayo Clin Proc. Jan 2005;80(1):116-20. [Medline].
Ram R, Natanzi N, Saadat P, Eliav D, Vadmal MS. Skin metastasis of pancreatic vasoactive intestinal polypeptide tumor: case report and review of the literature. Arch Dermatol. Jul 2006;142(7):946-7. [Medline].
Remme CA, de Groot GH, Schrijver G. Diagnosis and treatment of VIPoma in a female patient. Eur J Gastroenterol Hepatol. Jan 2006;18(1):93-9. [Medline].
Rigabert J, De Clermont H. [Diagnostic procedures and more particularly, place of scintigraphy in neuroendocrine tumors, example of vipoma in MEN 1]. Ann Endocrinol (Paris). Jun 2007;68(2-3):199-203. [Medline].
Rindi G, Candusso ME, Solcia E. Molecular aspects of the endocrine tumours of the pancreas and the gastrointestinal tract. Ital J Gastroenterol Hepatol. Oct 1999;31 Suppl 2:S135-8. [Medline].
Schonfeld WH, Eikin EP, Woltering EA, Modlin IM, Anthony L, Villa KF, et al. The cost-effectiveness of octreotide acetate in the treatment of carcinoid syndrome and VIPoma. Int J Technol Assess Health Care. Summer 1998;14(3):514-25. [Medline].
Smith SL, Branton SA, Avino AJ, Martin JK, Klingler PJ, Thompson GB, et al. Vasoactive intestinal polypeptide secreting islet cell tumors: a 15-year experience and review of the literature. Surgery. Dec 1998;124(6):1050-5. [Medline].
Stephen AE, Hodin RA. Neuroendocrine tumors of the pancreas, excluding gastrinoma. Surg Oncol Clin N Am. Jul 2006;15(3):497-510. [Medline].
Tauber MT, Harris AG, Rochiccioli P. Clinical use of the long acting somatostatin analogue octreotide in pediatrics. Eur J Pediatr. May 1994;153(5):304-10. [Medline].
Tomassetti P, Migliori M, Gullo L. Slow-release lanreotide treatment in endocrine gastrointestinal tumors. Am J Gastroenterol. Sep 1998;93(9):1468-71. [Medline].
Virgolini I, Traub-Weidinger T, Decristoforo C. Nuclear medicine in the detection and management of pancreatic islet-cell tumours. Best Pract Res Clin Endocrinol Metab. Jun 2005;19(2):213-27. [Medline].
Warner RR. Enteroendocrine tumors other than carcinoid: a review of clinically significant advances. Gastroenterology. May 2005;128(6):1668-84. [Medline].

