Elevated Serum Chromogranin-A and Characteristic Duodenal Enteroendocrine Cell Distribution in Pancreatic Fibrosis and Chronic Pancreatitis Compared with Other Dyspeptic Disorders: A Case Series Study

<b>Background</b>: Prior research has reported increased expression of duodenal chromogranin-A (CgA), secreted by enteroendocrine cells (EECs), in association with pancreatic fibrosis. However, it remains unknown whether serum CgA levels are also elevated, and whether there is a different distribution pattern of EECs in pancreatic fibrosis and other dyspeptic causes. Aims: This study had three main objectives. First, to compare the serum CgA level between patients with pancreatic fibrosis and those with other dyspeptic conditions. Second, to analyze the distribution pattern of duodenal EECs. Third, to evaluate whether biopsy results varied depending on the specific location within the duodenum. Serum CgA levels were categorized into low and high groups based on a cutoff value of 50 ng/mL. <b>Methods</b>: This cross-sectional prospective case series included 15 patients, with 4 patients in the low CgA group and 11 in the high CgA group. Each participant underwent a serum CgA test, transabdominal ultrasonography, pancreatic elastography, and upper gastrointestinal endoscopy. During endoscopy, a single gastric biopsy and three duodenal biopsies from different locations were obtained. <b>Results</b>: Patients in the high CgA group were generally older (52-68 years) than those in the low CgA group (37-55 years), with a statistically significant difference (<i>p</i> < 0.01). The high CgA group exhibited a clustered and centralized pattern of EECs, whereas the low CgA group showed a more discrete pattern with fewer EECs (<i>p</i> < 0.01). All duodenal ulcer cases were found in the low CgA group, while three cases of pancreatic fibrosis and one case of chronic pancreatitis were identified in the high CgA group. In the high CgA group, five cases of functional dyspepsia showed a band-like EEC distribution pattern, whereas cases with pancreatic fibrosis demonstrated a more uniformly scattered EEC distribution (<i>p</i> < 0.01). Consistency among intra-individual duodenal biopsy results was high across different biopsy sites. <b>Conclusions</b>: Elevated serum CgA (>50 ng/mL) and specific duodenal EEC distribution patterns may serve as potential diagnostic indicators for pancreatic fibrosis or chronic pancreatitis. These characteristics could help differentiate these conditions from functional dyspepsia.