Chronic Diarrhea Caused by Vasoactive Intestinal Peptide-Secreting Tumor

Abstract

VIPomas are a type of neuroendocrine tumor that independently produces vasoactive intestinal peptide (VIP). VIPomas causing watery diarrhea, hypokalemia, and achlorhydria (WDHA) syndrome are not frequently observed in adult patients without pancreatic ailments. However, in children, the occurrence of a VIPoma originating in the pancreas is exceedingly uncommon. Instead, WDHA syndrome is more commonly associated with neurogenic tumors that secrete VIP, often located in the retroperitoneum or mediastinum. Among infants, chronic diarrhea is a prevalent issue that often necessitates the attention of pediatric gastroenterologists. The underlying causes are diverse, and delays in arriving at a definitive diagnosis can give rise to complications affecting the overall well-being of the child. The authors present the case of an infant with chronic watery diarrhea, subocclusion manifestations, mild hypokalemia, and metabolic hyperchloremic acidosis secondary to a VIPoma in the retroperitoneum that was diagnosed via abdominal ultrasound and tomography. The laboratory results revealed lowered potassium levels and an excessive secretion of VIP. Following the surgical removal of the tumor, the diarrhea resolved, and both electrolyte levels and the imbalanced hormone levels returned to normal. Immunohistochemical examination confirmed the diagnosis of ganglioneuroblastoma, with N-MYC negative on molecular biology tests. We present the clinical and histo-genetic aspects of this rare clinical entity, with a literature review.

Keywords: diarrhea; ganglioneuroblastoma; infant; vasoactive intestinal polypeptide.

Figure 1

Radiographic indications of bowel distension with discernible air-fluid levels and the nonexistence of any lesion causing luminal occlusion.

Figure 2

Retroperitoneal tumor with calcifications, as shown on a CT scan.

Figure 3

The tumor’s macroscopic features include a brown color, an elastic consistency, and clear calcifications on each part.

Figure 4

Visualization of tumor cell nuclei characterized by conspicuous enlargement, accompanied by discernible nucleoli and cytoplasm exhibiting a dense eosinophilic nature: (a) Within the tumor cell population, minor regions of hemorrhage have been noted, 4× magnification; (b) observe the tumor’s growth pattern displaying either lobular or solid arrangements, accompanied by notable instances of dystrophic calcification, 10× magnification. The examination was performed using H&E staining. H score for NSE = 235, NF200 = 230, S100 = 298, GFAP = 288.

Figure 5

(a) Protein S100 demonstrated a robust and positive response in both Schwann cells and ganglion cells; (b) tumor cells exhibited a strong NSE expression, characterized by a cytoplasmic pattern of reactivity; (c) notably, tumor cells displayed a marked, widespread, and relatively uniform NF 200 expression; (d) GFAP demonstrated a moderate to strong positive expression in the ganglion cells. The magnification for the specimen was ×4.