Cronkhite-Canada syndrome complicated by ankylosing spondylitis and colon adenocarcinoma: a case report

Cronkhite-Canada syndrome (CCS) is an extremely rare non-hereditary syndrome (approximately 500 cases reported worldwide), characterized by diffuse gastrointestinal polyposis, ectodermal changes (alopecia, skin hyperpigmentation, onychodystrophy), and protein-losing enteropathy. Patients with CCS have a significantly increased risk of colorectal cancer, but its association with ankylosing spondylitis (AS) is rarely reported. We report a 62-year-old male patient who gradually developed restricted lumbar spine movement 30 years ago without a formal diagnosis at that time. In 2023, he was hospitalized for acute pancreatitis, and abdominal CT incidentally revealed “bamboo spine” changes. HLA-B27 testing was positive, leading to a clinical diagnosis of ankylosing spondylitis. In December 2025, he was admitted due to anorexia, alopecia, skin hyperpigmentation, and onychodystrophy. Gastroscopy revealed coarse and hypertrophic gastric mucosal folds with multiple nodular changes in the gastric fundus and body, and thickened, swollen, and rigid mucosa in the gastric antrum and angle; colonoscopy showed diffuse swelling of the entire colonic mucosa with nodular, polypoid, and raspberry-like changes. Pathology demonstrated chronic active inflammation with stromal edema in the gastric mucosa, colonic inflammatory polyps, and tubulovillous adenoma with carcinoma at the splenic flexure. The patient met the diagnostic criteria for Cronkhite-Canada syndrome proposed by Goto et al. and Watanabe et al., presenting with diffuse gastrointestinal polyposis, complete ectodermal triad (alopecia, skin hyperpigmentation, and onychodystrophy), and histopathological findings of inflammatory polyps with concurrent adenocarcinoma. He was treated with oral prednisone 20 mg/day and subsequently underwent left hemicolectomy with colostomy. The postoperative pathological stage was pT4aN0M0, Stage IIB. Postoperatively, the patient developed severe hypoalbuminemia (lowest albumin 17.8 g/L), generalized edema, subclavian vein thrombosis, recurrent infections, and stoma separation. To the best of our knowledge, this is the first reported case of CCS complicated by both colorectal adenocarcinoma and long-standing AS. This unique combination suggests that CCS may not be merely a gastrointestinal polyposis syndrome but a systemic disorder involving immune and neoplastic manifestations. Further studies are warranted to explore the immunological basis of this unique association.