Vasoactive Intestinal Polypeptide Secreting Tumor - VIPoma

  • Diagnosis
  • Background
  • Lab Tests
  • References
  • Related Content

Indications for Testing

  • Diarrhea without evident etiology

Laboratory Testing

  • Electrolytes – hypokalemia in 100% of patients
  • VIP level >75 pg/mL with secretory diarrhea is highly suggestive of VIPoma

Histology

  • Nested or trabecular arrangement of small- to medium-sized cells
    • Finely granular eosinophilic cytoplasm
    • Central, round-to-oval nuclei
    • Stippled chromatin (“salt and pepper”)
  • Immunohistochemistry – chromogranin A, synaptophysin, cytokeratin, Ki-67, NSE, PGP 9.5
    • Tumor-specific confirmation – VIP

Imaging Studies

  • CT/MRI or endoscopic ultrasound
  • Somatostatin-receptor scintigraphy

 Differential Diagnosis

Vasoactive intestinal polypeptide secreting tumors (VIPomas) are rare pancreatic neuroendocrine tumors associated with profuse diarrhea.

Epidemiology

  • Incidence – 1/10,000,000 (rare cause of functioning PNETs)
  • Age – median onset 40s
  • Sex – M:F, equal
  • Occurrence – sporadic, although some occur in association with multiple endocrine neoplasia type 1 (MEN1)
  • 60-80% of patients have metastatic disease at presentation

Risk Factors

  • Genetic – ~5% associated with MEN 1

Pathophysiology

  • Most tumors occur in the body and tail of the pancreas and are unifocal
  • Symptoms result from the secretion of vasoactive intestinal polypeptide (VIP)
    • VIP is an amino acid polypeptide that is a potent stimulator of intestinal secretion and inhibitor of gastric acid secretion
  • Other tumors can produce VIP – ganglioneuroblastoma, bronchogenic carcinoma, pheochromocytoma, and medullary thyroid carcinoma

Clinical Presentation

  • Verner-Morrison syndrome
    • Chronic watery diarrhea, hypokalemia, and achlorhydria (WDHA syndrome)
    • Profuse diarrhea (patients may exceed 6-8 L/day) causing dehydration, metabolic acidosis, and renal failure

Indications for Laboratory Testing

Tests generally appear in the order most useful for common clinical situations.
Click on number for test-specific information in the ARUP Laboratory Test Directory

Electrolyte Panel 0020410
Method: Quantitative Ion-Selective Electrode/Enzymatic

Vasoactive Intestinal Peptide 0099435
Method: Quantitative Radioimmunoassay

Chromogranin A by Immunohistochemistry 2003830
Method: Immunohistochemistry

Synaptophysin by Immunohistochemistry 2004139
Method: Immunohistochemistry

Pan Cytokeratin (AE1,3) by Immunohistochemistry 2003433
Method: Immunohistochemistry

Ki-67 with Interpretation by Immunohistochemistry 2007182
Method: Immunohistochemistry

Neuron Specific Enolase, Polyclonal (NSE P) by Immunohistochemistry 2004052
Method: Immunohistochemistry

Protein Gene Product (PGP) 9.5 by Immunohistochemistry 2004091
Method: Immunohistochemistry

Additional Tests Available

Pancreatic Polypeptide 0099436
Method: Quantitative Radioimmunoassay

Guidelines

NCCN Clinical Practice Guidelines in Oncology, Neuroendocrine Tumors. National Comprehensive Cancer Network. Fort Washington, PA [Accessed: Sep 2015]

O'Toole D, Grossman A, Gross D, Fave G, Barkmanova J, O'Connor J, Pape U, Plöckinger U, Mallorca Consensus Conference participants, European Neuroendocrine Tumor Society. ENETS Consensus Guidelines for the Standards of Care in Neuroendocrine Tumors: biochemical markers. Neuroendocrinology. 2009; 90(2): 194-202. PubMed

Protocol for the Examination of Specimens from Patients with Carcinoma of the Endocrine Pancreas. Based on AJCC/UICC TNM, 7th ed. Protocol web posting date: June 2012. College of American Pathologists (CAP). Northfield, IL [Accessed: Nov 2015]

Protocol for the Examination of Specimens from Patients with Neuroendocrine Tumors (Carcinoid Tumors) of the Small Intestine and Ampulla. Based on AJCC/UICC TNM, 7th ed. Protocol web posting date: June 2012. College of American Pathologists (CAP). Northfield, IL [Accessed: Sep 2015]

Protocol for the Examination of Specimens from Patients with Neuroendocrine Tumors (Carcinoid Tumors) of the Stomach. Based on AJCC/UICC TNM, 7th ed. Protocol web posting date: February 2010. College of American Pathologists (CAP). Northfield, IL [Accessed: Nov 2015]

Vinik A, Woltering E, Warner R, Caplin M, O'Dorisio T, Wiseman G, Coppola D, Go V, North American Neuroendocrine Tumor Society (NANETS). NANETS consensus guidelines for the diagnosis of neuroendocrine tumor. Pancreas. 2010; 39(6): 713-34. PubMed

Öberg K, Knigge U, Kwekkeboom D, Perren A, ESMO Guidelines Working Group. Neuroendocrine gastro-entero-pancreatic tumors: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Ann Oncol. 2012; 23 Suppl 7: vii124-30. PubMed

General References

Batcher E, Madaj P, Gianoukakis A. Pancreatic neuroendocrine tumors. Endocr Res. 2011; 36(1): 35-43. PubMed

Kapoor R, Moseley R, Kapoor J, Crapo L, Saint S. Clinical problem-solving. Needle in a haystack. N Engl J Med. 2009; 360(6): 616-21. PubMed

Oberg K. Pancreatic endocrine tumors. Semin Oncol. 2010; 37(6): 594-618. PubMed

Medical Reviewers

Last Update: January 2016