Filiform polyposis associated with sigmoid diverticulitis in a patient without inflammatory bowel disease

Filiform polyposis (FP) of the colon is an uncommon entity that is occasionally encountered in patients with inflammatory bowel disease (IBD). FP is morphologically characterized by multiple slender worm-like projections consisting of submucosal cores lined with normal mucosa. To date, only two cases of FP have been reported in patients with inflammatory conditions of the gastrointestinal tract other than ulcerative colitis or Crohn's disease. We report an additional case of FP occurring in an 83-year-old man with no history of IBD. The patient underwent anterior resection of the sigmoid colon for perforated diverticulitis. Around the diverticular orifice, localized FP involving a 13-cm colonic segment was observed. The filiform polyps consisted of submucosal fibrovascular cores lined with normal mucosa without epithelial dysplasia. To our knowledge, this is the first reported case of FP associated with colonic diverticulitis in a patient without IBD.