CHGA and cholelithiasis: Sakamoto et al found that epithelial metaplasia occurred in 11.7% of patients with cholelithiasis and expressed positive staining for neuroendocrine antigens like chromogranin A in 83.3% and serotonin in 50.0% of metaplastic cells.6 Other researchers insist on transformation from gallbladder adenocarcinoma.