giant inflammatory ( filiform ) polyposis is an uncommon benign lesion and is usually associated with inflammatory bowel disease ( ibd ) . long - term inflammation of the colonic mucosa during chronic ibd with alternating periods of ulceration and healing may lead to the formation of finger - like projections [ 1 , 2 ] . in rare cases , a giant inflammatory polyposis forms a large tumor mass [ 3 , 4 , 5 , 6 , 7 ] . on colonoscopy and radiologic studies , numerous filiform polyps appear as a  mass of worms or as a  fungating mass ; hence , this condition is easily confused with cancer . inflammatory polyps or pseudopolyps are the most common lesions observed both in ulcerative colitis ( uc ) and crohn 's disease ( cd ) [ 8 , 9 , 10 , 11 , 12 ] . moreover , in some cases , the polyps contain both mucosal and submucosal tissue , indicating initial inflammatory involvement of the deeper bowel layers . they are composed of a central core of submucosal connective tissue coated by normal , non - inflamed mucosa . here , we report the case of a patient with uc with large tumors obstructing the transverse and descending colon , who presented with severe diarrhea and melena . a 25-year - old japanese man with an uc history of 2 years and 6 months was successfully treated with prednisolone . the disease was in remission and his symptoms had been relieved . however , the disease flared up and the patient was admitted to our hospital because of severe abdominal pain and bloody diarrhea . physical examination revealed direct soreness and masses in the upper and left lower abdominal sites . blood examination revealed anemia ( hemoglobin level 5.5 g / dl [ normal 11.515.0 ] ) , hypoproteinemia ( protein level 4.6 g / dl [ normal 6.78.3 ] ) and hypoalbuminemia ( albumin level 1.9 g / dl [ normal 3.85.3 ] ) . computed tomography ( ct ) imaging showed bowel wall thickening of the transverse and descending colon , which raised suspicion of wall thickening of several segments of the small bowel . the ct scan also demonstrated localized high - density areas in the lumen of the transverse and descending colon ( fig . a colonoscopy revealed a large mass with numerous white - pale reddish polyps of complex shape in the descending colon . based on this examination , colon carcinoma was strongly suspected , and several biopsies were performed . histology of the examined sections indicated uncharacteristic inflammatory changes in the mucosa , but no cellular dysplasia . , we observed one tumor measuring 23  18 cm in the transverse colon and another measuring 14  13 cm in the descending colon . there were no obvious areas of ulceration , although each tumor had a coral - reef - like surface with numerous soft , finger - like polyps ( up to 5 cm in diameter ) projecting into the lumen . the cross - section of the tumors showed that narrow strings of tissue were interconnected , forming multiple , variably sized spaces inside the tumors ( fig . 2 ) . the surrounding fat tissue was unaffected , and no suspicious lymph nodes were detected . microscopic examination revealed that the tumors comprised strings of fibrotic connective tissue , lined by inflamed colonic mucosa , and the surrounding spaces were filled with fecal and mucoid materials . a fibrovascular core and inflammatory polyposis were evident from the submucosa to the proper muscular layer and the submucosa had partially disappeared in both the elevated and the depressed lesions . the polyps contained regenerative and hyperplastic muscularis mucosa with an arborized and thickened configuration ( fig . the crypt architecture was normal , and no epithelial atypia of the polyps was noted . the mucosal inflammation consisted of lymphocytes , plasma cells , eosinophils and lymphoid follicles . neutrophil infiltration , cryptitis , crypt abscess , which is characteristic of active uc , and paneth cell metaplasia were found in the transverse colon ( fig . sections through the bowel wall near the mass showed colonic mucosa with regenerative features , including architecturally mildly distorted glands , but without active inflammatory changes ( fig . finally , histopathological examination of the resected colon led to the diagnosis of giant inflammatory ( filiform ) polyposis associated with uc . inflammatory polyps are a common complication in patients with ibds such as uc and cd , accounting for approximately 1020% of all cases . inflammatory polyps may originate from the regenerative mucosa in the remission stage after an acute recurrence of uc or cd . in rare cases , numerous large - sized polyps are present , and this condition is known as giant inflammatory ( filiform ) polyposis [ 8 , 9 , 10 , 11 , 12 ] . these polyps are associated with cd in approximately two - thirds of cases and with uc in one - third of cases . giant inflammatory polyposis can be localized in one segment of the colon , or numerous polyps can be diffusely involved in the entire colon . the transverse colon is the most common site , followed by the sigmoid and descending colon , the cecum and the splenic and hepatic flexures . in our case , the clinical features of the reported cases indicate that the time from the initial diagnosis of uc to confirmation of giant inflammatory polyposis ranged from 3 to 276 months . in our patient patients may present with various symptoms , including anemia , weight loss , cramping abdominal pain , diarrhea , passage of blood through the rectum and colonic obstruction . most patients go undiagnosed until they develop signs and symptoms of obstruction , hemorrhage and anemia [ 1 , 2 , 14 ] . the pathogenesis of giant inflammatory polyposis is considered to result from enlarged mucosal tags , caused by repeated peristalsis and fecal stream . giant inflammatory polyposis may be related to postinflammatory regeneration or hyperplastic proliferation of the colonic mucosa between ulcerations . the histopathological features include inflammatory infiltrates overlying the muscularis mucosae , deep fissure - like ulcers , chronic mucosal inflammation with lymphoid hyperplasia and nerve hyperplasia in the surrounding mucosa [ 1 , 2 , 4 , 5 , 6 , 15 ] . giant inflammatory polyposis in uc may be a consequence of severe inflammation rather than of increased duration of the disease . in summary , we present the case of a japanese patient with uc who was diagnosed with giant inflammatory polyposis localized in the transverse and descending colon . severe ulcerative inflammation and its repair process may have caused the development of the giant inflammatory polyps .
we report a unique case of giant obstructing inflammatory polyposis associated with ulcerative colitis ( uc ) . 
 a 25-year - old japanese man with an uc history of 2 years and 6 months was referred to our institution because of diarrhea and melena . 
 his computed tomography scan showed marked dilation of the transverse and descending colon ; therefore , we performed total colectomy . 
 macroscopic evaluation of the excised specimen indicated constricting lesions with giant polyposis in the transverse and descending colon . 
 the polyposis consisted of narrow worm- or noodle - like polyps that bridged over the irregular ulcers . 
 histologic evaluation of the excised specimen indicated transmural inflammation with a thickened proper muscular layer overlaid with inflammatory polyposis . based on these data , a diagnosis of giant inflammatory polyposis 
 should be considered in patients who have had uc . 
 although giant inflammatory polyposis is considered benign , surgical treatment may be indicated to avoid serious complications .