[Clinicopathologic features of Cronkhite-Canada syndrome and the significance of IgG4-positive plasma cells infiltration].

Objective To analyze the clinical and pathological features of Cronkhite-Canada syndrome (CCS), and to investigate the significance of IgG4 positive plasma cell infiltration. Methods Clinical presentations, endoscopic appearances and morphological features of 18 patients diagnosed with CCS at Peking Union Medical College Hospital during 2000-2016 were included in the study.There were 11 male and 7 female patients. IgG4 and IgG immunohistochemical stains were performed in total of 55 biopsies from the patients (36 polyps, 10 adenoma and 9 surrounding mucosa) and a control group of 58 cases (19 colonic mucosa, 7 colonic hyperplastic polyps, 9 inflammatory bowel disease and 23 adenoma). Results Average age of CCS was 59 years (range 47-69 years) and the male to female ratio was 11∶7. All patients had at least one ectoderm lesion. Fourteen cases had testicular abnormalities. Digestive tract symptoms were encountered in most cases. Four patients had a history of connective tissue disease. Endoscopically, multiple polyps were found to involve entire gastrointestinal tract except the esophagus. Morphologically, CCS polyps were characterized by prominent mucosal edema, mild to moderate inflammation, glands hyperplasia and cystic dilatation. Ten cases had colonic adenoma and one case had rectal adenocarcinoma. While none of the cases reached the diagnostic criteria of IgG4 disease, the positive rate of IgG4 positive plasma cells in adenoma of CCS was significantly higher than that in polyps and surrounding mucosa of CCS (60.0%∶13.9%∶0, P<0.01). The positive rate of IgG4 positive plasma cells of adenoma and polyp of CCS had an increased tendency compared to that of adenoma and polyp of control group (60.0%∶34.8%; 13.9%∶0). Conclusion The findings in the study do not support that CCS is a variant of IgG4 disease, although IgG4 positive plasma cells may be involved in the pathogenesis of CCS, which may be explored in future investigations. Key words: Intestinal polyposis; Plasma cells; Autoimmune diseases; Cronkhite-Canada syndrome