A case of Cronkhite-Canada syndrome with repeated linked color imaging observation of the subepithelial capillary network in the colon.

Cronkhite-Canada syndrome (CCS) is a non-hereditary disorder characterized by non-neoplastic gastrointestinal polyposis and ectodermal changes. While corticosteroids are considered effective, some cases are refractory. A 48-year-old woman presented with diarrhea, anorexia, and epigastralgia lasting for 3 months. She suffered from alopecia and nail dystrophy. Gastrointestinal endoscopy with histological examination confirmed non-neoplastic polyposis from the stomach to the rectum, confirming the diagnosis of CCS. Linked color imaging (LCI) with magnified endoscopy revealed a ribbon-like proliferation of capillaries surrounding the pits in the colonic mucosa. Histologically, the polyps had dilated glands, edematous stroma with inflammatory cell infiltrates and increased capillaries just beneath the epithelium. Immunohistochemical examination confirmed the expression of vascular endothelial growth factor (VEGF), mainly in the superficial epithelial and crypt cells. Steroid therapy was ineffective, and concomitant infliximab therapy provided symptomatic relief. Although symptoms rapidly improved with combination therapy, capillary hyperplasia and slight inflammation persisted in the colon mucosa after polyp resolution. Withdrawal of steroid treatment resulted in flare-ups of symptoms and polyps. Repeated magnified observations at LCI during post-relapse retreatment clearly captured the resolution process of both neovascularization and inflammation. Once the capillary hyperplasia and inflammation subsided, the steroid could be tapered off without relapse. To our knowledge, this is the first report describing the involvement of VEGF-induced angiogenesis and LCI findings in CCS; LCI observations are useful not only in the active phase of CCS, but also in determining subtle capillary hyperplasia and residual inflammation in remission, which may be an indicator of continued treatment.