Session: MON 306-326-Neoplasia of Endocrine Tissues: Case Reports
Poster Board MON-315
VIPoma is a rare neuroendocrine tumor with the usual clinical presentation with WDHA syndrome (watery diarrhea, hypokalaemia and achlorhydria). Clinical suspicion leading to the diagnosis depends on an elevated serum Chromogranin A (CgA), 5-HIAA and serum VIP concentrations. We describe a case of VIPoma who presented with WDHA syndrome. Interestingly, a normal serum CgA concentration was seen. We discuss possible reasons for the discrepancy.
A 37 years old man presented with chronic diarrhea for 1 year requiring multiple hospitalizations. Physical examination revealed cachexia, dehydration and hyperactive bowel sounds. Investigations showed metabolic acidosis, dehydration and severe hypokalemia. CT showed a 3.4 x 5.8 pancreatic tail mass with a small liver segment lesion, suggestive of liver metastasis.Plasma CEA, CA19-9 and 24-hour 5HIAA were normal. CgA was 22.4 ug/L (0.0-100.0), 5HIAA was 12.9 umol/day (3.6 – 42.6). A FNA cytology
of the tumor under EUS was suggestive of a neuroendocrine tumor. A trial of octreotide showed good response. He underwent a distal pancreatectomy, splenectomy and wedge resection of hepatic lesions. VIP was elevated at 530 pg/ml (reference interval <75 pg/ml). Histology described a 7.5cm infiltrative neuroendocrine tumor with acinar and trabecular pattern of growth, speckled chromatin pattern, mild to moderate nuclear pleomorphism and granular eosinophilic cytoplasm. Positive staining with synaptophysin, chromogranin and cytokeratin AE1/3 present. The elevated serum VIP level and pancreatic neuroendocrine lesion is congruent with the diagnosis of VIPoma. His symptoms resolved completed and the VIP concentration normalised.
CgA can be used as a robust screening and prognostic marker for neuroendocrine tumour. CgA had been found to be elevated in all VIPoma patients especially in patients with liver metastases in one study (1).In this case the CgA and 5 H-IAA were normal although the VIP levels were very high and the patient had a relatively large tumor with liver metastases. CgA production depend on tumor type and differentiation with a low sensitivity in moderately or poorly differentiated neuroendocrine tumor. Another possible reason may be limitations of the assay which can only detect intact CgA so post translational cleavage may lead to decreased levels.
Nothing to Disclose: HL, HTK, DEKC, SL, MKSL, RD
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