Background: Granulomatosis with polyangiitis (GPA) induces respiratory tract and kidney granulomatous inflammation due to small-vessel vasculitis. However, gastrointestinal involvement, and especially colon perforation, is rare.
Case presentation: A 40-year-old man diagnosed with GPA was admitted to our hospital for GPA management. He was started on anti-cluster of differentiation 20 antibody (rituximab) therapy after admission and suffered severe abdominal pain 2 weeks later. A clinical diagnosis of sigmoid colon perforation was made, and we performed sigmoid colon resection with colostomy. Histopathological examination revealed loss of vascular wall and neutrophil infiltration. He was discharged from the hospital after intravenous immune globulin therapy.
Conclusions: Although gastrointestinal involvement is rare in GPA, severe complications require surgical intervention. Bowel perforation should be considered an important complication of GPA.
Keywords: Gastrointestinal involvement; Granulomatosis with polyangiitis; Sigmoid colon perforation.