Editing VIPoma

{{Short description|A rare neuroendocrine tumor that causes watery diarrhea and electrolyte imbalance}}
{{Infobox medical condition
| name = VIPoma
| synonyms = Verner–Morrison syndrome, Pancreatic cholera, WDHA syndrome (Watery Diarrhea, Hypokalemia, and Achlorhydria)
| pronounce = {{IPAc-en|v|ɪ|ˈ|p|oʊ|m|ə}}
| field = [[Oncology]], [[Endocrinology]]
| symptoms = Profuse watery diarrhea, dehydration, flushing, cramping, weakness
| complications = [[Hypokalemia]], [[achlorhydria]], [[metabolic acidosis]], [[renal failure]], [[malnutrition]]
| onset = Typically adults aged 30–50
| duration = Chronic unless treated
| types = Pancreatic or extrapancreatic neuroendocrine tumor
| causes = [[Neoplasm]] of VIP-secreting cells
| risks = [[Multiple endocrine neoplasia type 1]]
| diagnosis = [[Plasma]] VIP level, imaging ([[CT scan]], [[MRI]], [[somatostatin receptor scintigraphy]])
| differential = [[Cholera]], [[Carcinoid syndrome]], [[laxative abuse]], [[Zollinger–Ellison syndrome]]
| prevention = None known
| treatment = [[Surgical resection]], [[somatostatin analogs]], supportive care
| medication = [[Octreotide]], [[Lanreotide]], electrolyte replacement
| prognosis = Variable; often poor in metastatic cases
| frequency = ~1 per 10 million annually
| deaths = Associated with complications of metastatic disease or severe dehydration
}}
'''VIPoma''' is a rare type of [[neuroendocrine tumor]] that secretes excessive amounts of [[vasoactive intestinal peptide]] (VIP), a hormone involved in regulating intestinal water and electrolyte secretion. The excessive VIP leads to a distinct clinical syndrome characterized by profound watery diarrhea, hypokalemia (low potassium), and achlorhydria (lack of stomach acid), collectively known as '''WDHA syndrome''' or '''Verner–Morrison syndrome'''. It is also colloquially referred to as '''pancreatic cholera''' due to the similarity of symptoms to [[cholera]] infection.

== Pathophysiology ==
VIPomas most commonly originate from the [[pancreas]], particularly the [[non-β islet cells]], although rare cases have been found in extrapancreatic sites such as the [[bronchus]], [[adrenal gland]], or [[colon]]. Approximately 50–75% of VIPomas are [[malignant tumor|malignant]] at the time of diagnosis, frequently with metastasis to the [[liver]] or [[lymph nodes]].

The excessive VIP causes increased intestinal secretion of water and electrolytes, reduced gastric acid secretion, and smooth muscle relaxation, resulting in:

* Chronic watery diarrhea (often exceeding 3 liters/day)
* Electrolyte disturbances including [[hypokalemia]], [[hypochlorhydria]], and [[metabolic acidosis]]
* Systemic vasodilation leading to [[flushing]] and [[hypotension]]
* Possible [[hypercalcemia]] and [[hyperglycemia]]

== Clinical Presentation ==
Patients with VIPoma typically present with:

* Severe, persistent watery diarrhea (even during fasting)
* [[Dehydration]]
* Muscle weakness, cramping
* Weight loss
* [[Facial flushing]]
* [[Hypotension]]
* Nausea or vomiting (less common)

== Diagnosis ==
Diagnosis involves a combination of clinical suspicion and confirmatory tests:

* '''Laboratory tests:'''
* Elevated serum VIP levels (>75 pg/mL)
* Electrolyte imbalances: low potassium, low bicarbonate
* Metabolic acidosis on [[arterial blood gas]]
* '''Imaging:'''
* [[Computed tomography|CT scan]] or [[magnetic resonance imaging|MRI]] to localize tumor
* [[Somatostatin receptor scintigraphy]] (Octreoscan) or [[68Ga-DOTATATE PET/CT]] to detect somatostatin receptor-positive lesions
* [[Endoscopic ultrasound]] in select cases

== Treatment ==
Treatment strategies include:

=== Medical Management ===
* '''[[Octreotide]]''' or '''[[Lanreotide]]''' – long-acting [[somatostatin analogs]] that inhibit VIP secretion and reduce diarrhea
* '''IV fluid and electrolyte replacement''' – to manage dehydration and correct imbalances
* '''Antidiarrheal agents''' – adjunctive, but generally not effective alone

=== Surgical Management ===
* '''Surgical resection''' – curative if the tumor is localized
* '''Debulking surgery''' – may help in metastatic cases to control hormone secretion

=== Advanced/Metastatic Disease ===
* '''Targeted therapy''' – e.g., everolimus, sunitinib
* '''Peptide receptor radionuclide therapy''' (PRRT) for somatostatin receptor-positive tumors
* '''Hepatic artery embolization''' or ablation for liver metastases

== Prognosis ==
The prognosis of VIPoma depends on tumor size, location, and metastatic spread. Localized VIPomas have a good prognosis with surgical resection, while metastatic VIPomas have a poorer outcome. However, symptom control with somatostatin analogs can significantly improve quality of life.

== Epidemiology ==
VIPomas are extremely rare, with an estimated incidence of approximately 1 per 10 million people per year. They typically occur in adults aged 30–50, with equal incidence in males and females. They may be associated with [[multiple endocrine neoplasia type 1]] (MEN1).

== See Also ==
* [[Neuroendocrine tumor]]
* [[Somatostatin]]
* [[Multiple endocrine neoplasia]]
* [[Carcinoid syndrome]]
* [[Pancreatic cancer]]

== External links ==
{{Medical resources
| DiseasesDB = 13877
| ICD10 = {{ICD10|C|25|4|c|15}} or {{ICD10|E|16|8|e|15}}
| ICD9 =
| ICDO = {{ICDO|8155|3}}
| OMIM =
| MedlinePlus = 000228
| eMedicineSubj = med
| eMedicineTopic = 2379
| eMedicine_mult = {{eMedicine2|med|2399}} {{eMedicine2|ped|2428}}
| MeshID = D003969
| SNOMED CT = 447643008
| Orphanet = 97282
}}
{{Gastrointestinal diseases}}
{{Oncology}}
{{Tumor morphology}}
{{Endocrine gland neoplasia}}
[[Category:Endocrine neoplasia]]
[[Category:Rare cancers]]
[[Category:Syndromes]]