Cap Polyposis of Colon Due to Helicobacter pylori Infection Masquerading as Inflammatory Bowel Disease

Abstract

Purpose: Cap polyposis is a rare disorder characterized by the presence of inflammatory colonic polyps in patients with underlying constipation. The etiopathogenesis is unclear, and H. pylori has been suggested as a causative organism. Only six cases of cap polyposis associated with H. pylori have been reported so far. We report a case that was misdiagnosed as Crohn's disease, but further work-up revealed cap polyposis in the setting of H. pylori infection and chronic constipation. A 59-year-old female was referred to our clinic for management of Crohn's disease. She had a history of chronic constipation, and presented to an outside facility with intermittent lower abdominal pain and hematochezia. Colonoscopy had revealed multiple ulcerated polyps from the sigmoid colon to hepatic flexure. Pathology showed polypoid fragments of ulcerated and inflamed granulation tissue with prolapse or hamartomatous features. She was diagnosed with Crohn's disease and initiated on prednisone. The patient presented to our institution for evaluation of persistent symptoms. Colonoscopy revealed multiple 2-20 mm polyps with overlying ulceration and exudate (Figure) in the entire colon, with rectal sparing. The interposed colonic mucosa and terminal ileum appeared normal. Pathology revealed erosions on the polyp surface, cystically dilated crypts with mucoid exudate and inflammatory cells. The diagnosis of cap polyposis was made based on clinical, endoscopic and pathologic features. Esophagogastroduodenoscopy was normal, but H. Pylori immunostatin was positive on gastric biopsies. The patient was initiated on H. pylori eradication treatment and prednisone was recommended to be tapered. The patient reported clinical improvement and a follow-up colonoscopy has been planned.Figure: Ulcerated polyps.Conclusion: Cap polyposis is a rare and benign disorder characterized by the presence of inflammatory polyps, which are covered by a “cap” of granulation tissue. Thirty cases have been reported in the literature, and, similar to our case, were initially misdiagnosed as Crohn's disease or ulcerative colitis. The exact etiology of cap polyposis remains unknown. Treatment regimen is not standardized, but H. pylori eradication has been reported. Review of further cases is necessary to establish a common pathophysiology and standardize the treatment regimen.