Table of Contents
Definition / general | Essential features | Terminology | ICD coding | Epidemiology | Sites | Pathophysiology | Etiology | Clinical features | Diagnosis | Radiology images | Prognostic factors | Case reports | Treatment | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Electron microscopy images | Molecular / cytogenetics description | Sample pathology report | Differential diagnosis | Board review style question #1 | Board review style answer #1 | Board review style question #2 | Board review style answer #2Cite this page: Gonzalez R. VIPoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/pancreasvipoma.html. Accessed April 19th, 2024.
Definition / general
- Well differentiated neuroendocrine tumor that secretes vasoactive intestinal peptide (VIP), leading to chronic watery diarrhea
Essential features
- Functional well differentiated neuroendocrine tumor (WD-NET) that secretes vasoactive intestinal peptides
- Histology is same as other well differentiated neuroendocrine tumors in pancreas
- Clinical diarrhea can be severe, possibly fatal (may exceed 8 liters of stool in 24 hours) (South Dartmouth (MA): MDText.com, Inc;2017 Jun 5)
Terminology
- VIPoma syndrome is also termed Verner-Morrison syndrome and WDHA syndrome (watery diarrhea, hypokalemia, achlorhydria) (Rom J Morphol Embryol 2017;58:371)
ICD coding
Epidemiology
- Incidence is roughly 1 per 10 million persons per year (Surg Clin North Am 1987;67:379)
- Mean age 51 years
Sites
- 90% of VIPomas arise from pancreas (Am J Med 1987;82:37)
- Most common pancreatic location is tail (Surgery 1998;124:1050)
Pathophysiology
- VIP stimulates intestinal secretion of water and electrolytes, causing VIPoma syndrome when excessive
Etiology
- Most cases are sporadic but about 5% occur in the setting of multiple endocrine neoplasia 1 syndrome (MEN1)
Clinical features
- Chronic secretory diarrhea hypokalemia, achlorhydria, flushing, hypercalcemia (Hepatogastroenterology 2005;52:1259)
Diagnosis
- Imaging to detect pancreatic mass
- Elevated plasma vasoactive intestinal levels
Prognostic factors
- Often metastatic at time of diagnosis (Surgery 1998;124:1050)
- Median survival is roughly 6 years (Pancreas 2019;48:934)
- Poor prognostic factors: age < 40 years or > 60, size > 4 cm, poor clinical management of water, electrolyte and acid base profiles, metastatic disease, unresectability (J Clin Case Rep 2012,2:15)
Case reports
- 13 year old girl with multiple endocrine neoplasia 1 syndrome and pancreas mass (Indian J Endocrinol Metab 2013;17:S215)
- 46 year old woman with 18 cm tumor (World J Surg Oncol 2008;6:80)
- 47 year old man with sporadic tumor (Hematol Oncol Stem Cell Ther 2014;7:109)
- 74 year old man with diarrhea, weight loss and liver metastasis (Case Rep Gastroenterol 2019;13:225)
Treatment
- Surgical resection of primary lesion, if possible
- Hepatic metastases can be resected or embolized
- Octreotide for metastatic disease
Gross description
- Single or multiple lesions, most commonly in tail of pancreas
- Firm, homogeneous, well circumscribed
Microscopic (histologic) description
- Nests of monotonous low grade neuroendocrine cells with salt and pepper nuclei and ample amphophilic cytoplasm, as with any other well differentiated neuroendocrine tumor
Positive stains
- VIP (though this does not establish the diagnosis)
- Synaptophysin, chromogranin
- PDX1, INSM1 (Am J Surg Pathol 2012;36:737)
Negative stains
Molecular / cytogenetics description
- Overexpression of CXCR4, down regulation of MSH2 in one case (World J Surg Oncol 2012;10:264)
Sample pathology report
- Pancreas and duodenum, Whipple procedure:
- Well differentiated neuroendocrine tumor of pancreas (see comment and synoptic report)
- Comment: Based on the patient's clinical symptoms, this neuroendocrine tumor is best considered a VIPoma.
Differential diagnosis
- Nongastrin secreting pancreatic neuroendocrine tumor:
- No histopathologic differences; must be determined on clinical grounds
Board review style question #1
What is the most common symptom of a VIPoma?
- Abdominal pain
- Acromegaly
- Diarrhea
- Necrotizing migratory erythema
- Weakness
Board review style answer #1
Board review style question #2
Board review style answer #2