VIPoma pathophysiology
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Madhu Sigdel M.B.B.S.[2]Parminder Dhingra, M.D. [3]
Overview
A VIPoma is a rare tumor of the non-beta cells of the pancreas that results in the overproduction of the hormone vasoactive intestinal peptide (VIP). On microscopic histopathological analysis, findings of VIPoma are composition of uniform, small to intermediate-sized cells in clusters, nests, and trabecular growth patterns with hyperchromatic nuclei and scant cytoplasm.[1][2]
Pathophysiology
- VIPoma causes cells in the pancreas to produce high levels of a hormone called vasoactive intestinal peptide (VIP).
- Vasoactive intestinal peptide hormone stimulates secretions from the intestine and pancreas, inhibits gastric acid secretion, increases glycogenolysis, causes hypercalcemia and relaxes sphincters and circular smooth muscles of gut.
- Vasoactive intestinal peptide (VIP) is a structural homologue of secretin.
- Elevated serum VIP levels cause increased intestinal secretion of Na+, K+, HCO3 -, and Cl-, as well as bone resorption, vasodilation, and inhibition of gastric acid section.[2]
- VIPomas are neuroendocrine neoplasms arising from the pancreas in 90% of the cases reported, while the remaining 10% occur in other tissues of neural crest origin.[1]
- VIPomas originate in amine precursor uptake and decarboxylation (APUD) cells of the gastroenteropancreatic endocrine system and in adrenal or extra-adrenal neurogenic sites.[1]
- When VIPoma is found in the pancreas, 75% of the tumors occur in the corpus and cauda, while 25% occur in the pancreatic head.[1]
Gross Pathology
On gross pathology, circumscribed, solid mass composed of tan, uniform, fleshy parenchyma are characteristic findings of VIPoma.
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![Surgical specimen showing the body, tail and peripancreatic nodule (arrow).[3]](/images/5/57/Surgical_specimen.jpg)
Surgical specimen showing the body, tail and peripancreatic nodule (arrow).[3]
![Surgical specimen showing the body, tail and peripancreatic nodule (arrow).[3]](/index.php/File:Surgical_specimen.jpg)
Microscopic Pathology
- Histologically, a VIPoma demonstrates a composition of uniform, small to intermediate-sized cells in clusters, nests, and trabecular growth patterns with hyperchromatic nuclei and scant cytoplasm. A few nests may also exhibit psuedorosettes.
- Immunohistochemistry of VIPoma typically demonstrates positive immunoreactivity for vasoactive intestinal peptide, cytokeratin, neuron specific enolase, chromogranin, synaptophysin, and somatostatin, with negative reactivity for S100, calcitonin, PSA, CEA, insulin, glucagon, and growth hormone.[1]
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![(A) Typical of pancreatic neuroendocrine tumors, this lesion contains interconnecting nests and trabeculae of uniform cuboidal cells with granular cytoplasm and central round nuclei within a hyalinized, well-vascularized stroma (Original magnification ×100). (B) The tumor deeply invades the muscularis propria of the stomach.[2]](/images/3/35/Histology.jpg)
(A) Typical of pancreatic neuroendocrine tumors, this lesion contains interconnecting nests and trabeculae of uniform cuboidal cells with granular cytoplasm and central round nuclei within a hyalinized, well-vascularized stroma (Original magnification ×100). (B) The tumor deeply invades the muscularis propria of the stomach.[2]
![(A) Typical of pancreatic neuroendocrine tumors, this lesion contains interconnecting nests and trabeculae of uniform cuboidal cells with granular cytoplasm and central round nuclei within a hyalinized, well-vascularized stroma (Original magnification ×100). (B) The tumor deeply invades the muscularis propria of the stomach.[2]](/index.php/File:Histology.jpg){kind=small}
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Natanzi, Naveed; Amini, Mazyar; Yamini, David; Nielsen, Shawn; Ram, Ramin (2009). "Vasoactive Intestinal Peptide Tumor". Scholarly Research Exchange. 2009: 1–7. doi:10.3814/2009/938325. ISSN 1687-8299.
- ↑ 2.0 2.1 2.2 Joyce, David L; Hong, Kelvin; Fishman, Elliot K; Wisell, Joshua; Pawlik, Timothy M (2008). "Multi-visceral resection of pancreatic VIPoma in a patient with sinistral portal hypertension". World Journal of Surgical Oncology. 6 (1): 80. doi:10.1186/1477-7819-6-80. ISSN 1477-7819.
- ↑ APODACA-TORREZ, Franz R.; TRIVIÑO, Marcello; LOBO, Edson José; GOLDENBERG, Alberto; TRIVIÑO, Tarcísio (2014). "Extra-pancreatic vipoma". ABCD. Arquivos Brasileiros de Cirurgia Digestiva (São Paulo). 27 (3): 222–223. doi:10.1590/S0102-67202014000300015. ISSN 0102-6720.