Vainer B, Jess T, Andersen PS. Rapid tumour-like growth of giant filiform polyposis in a patient without a history of chronic bowel inflammation. APMIS 2007;115:1306–1310. Long-term inflammation of the colonic mucosa during chronic inflammatory bowel disease with alternating periods of ulceration and healing may lead to the formation of finger-like projections, so-called filiform polyps. In rare cases, several filiform polyps form large tumour masses, termed giant filiform polyposis. We present a case of giant obstructing filiform polyposis in a patient without previous evidence of chronic bowel inflammation. The resected ascending colon from a 37-year-old woman was evaluated macroscopically and microscopically, and the presence of gene polymorphisms was studied by means of multiplex capillary electrophoresis single-strand conformation polymorphism assay, DNA sequencing, TaqMan analysis, and restriction enzyme cleavage. The giant filiform polyposis was restricted to a 15 cm segment of the ascending colon, and the remaining colonic mucosa was entirely without inflammatory changes. During the post-operative follow-up period, the patient developed symptoms and signs of distal bowel inflammation. Gene polymorphism studies were inconclusive as to Crohn's disease. In conclusion, we present an unusual pathological entity of giant filiform polyposis, which developed relatively rapidly in a colon without any history or macroscopic changes suggestive of chronic inflammatory bowel disease. Although the patient subsequently developed symptoms in keeping with Crohn's disease, studies of genetic polymorphism were unable to confirm this notion, and colorectal tissue has not been sampled postoperatively for histological evaluation.