title: Isolated recto-sigmoid colitis: a new imaging pattern of ipilimumab-associated colitis.
abstract: OBJECTIVE
  The purpose of this study is to describe typical CT findings and distinct imaging patterns of ipilimumab-associated colitis in immunotherapeutic treatment of melanoma.
  
  
  METHODS
  This HIPAA-compliant retrospective study included 86 patients with melanoma imaged with CT or PET/CT of the abdomen and pelvis during or shortly after administration of ipilimumab. Twelve of 86 patients (14%) developed symptoms of colitis and underwent CT imaging of the abdomen and pelvis while symptomatic. Two radiologists reviewed CT images to evaluate for the presence of CT findings of colitis including mesenteric vessel engorgement, pericolonic inflammatory change, hyperenhancement of colonic mucosa, colonic wall thickening, fluid-filled colonic distension, pneumoperitoneum, pneumatosis, and diverticulosis in the inflamed segment of colon. One nuclear medicine radiologist reviewed PET images for abnormally increased FDG uptake in the colon. The diagnosis of ipilimumab-associated colitis was made based on clinical presentation, imaging findings, and laboratory data.
  
  
  RESULTS
  Common CT findings of ipilimumab-associated colitis included colonic mucosal hyperenhancement (10/12 [83%]), mesenteric vessel engorgement (9/12 [75.0%]), colonic wall thickening (9/12 [75%]), and pericolonic fat stranding (2/12 [16%]). No patient developed pneumatosis or pneumoperitoneum. Diffuse colitis was present in 4/12 (33%) patients. Segmental colitis with associated diverticulosis (was present in 2/12 (17%) patients). A third pattern, isolated recto-sigmoid colitis without diverticulosis, was observed in 6/12 (50%) patients. All patients with colitis demonstrated recto-sigmoid involvement.
  
  
  CONCLUSIONS
  A third radiologic pattern of ipilimumab-associated colitis was observed in this study: isolated recto-sigmoid colitis without diverticulosis. All patterns of ipilimumab-associated colitis include recto-sigmoid involvement.
authors: Department of Radiology, Duke University Medical Center, Box 3808, Durham, NC, 27710, USA.
authors: Andrew R
authors: AR
authors: Barina
authors: Department of Radiology, Duke University Medical Center, Box 3808, Durham, NC, 27710, USA.
authors: Mustafa R
authors: MR
authors: Bashir
authors: Department of Radiology, Duke University Medical Center, Box 3808, Durham, NC, 27710, USA.
authors: Brandon A
authors: BA
authors: Howard
authors: Department of Medicine, Duke University Medical Center, Durham, NC, USA.
authors: Brent A
authors: BA
authors: Hanks
authors: Department of Medicine, Duke University Medical Center, Durham, NC, USA.
authors: April K
authors: AK
authors: Salama
authors: Department of Radiology, Duke University Medical Center, Box 3808, Durham, NC, 27710, USA. jaffe002@mc.duke.edu.
authors: Tracy A
authors: TA
authors: Jaffe
mesh_terms: D000368:Aged; D000911:Antibodies, Monoclonal / Q000009:adverse effects*; D003092:Colitis / Q000139:chemically induced* / Q000000981:diagnostic imaging*; D012809:Colon, Sigmoid; D003287:Contrast Media; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007479:Iopamidol; D000074324:Ipilimumab; D008297:Male; D008545:Melanoma / Q000188:drug therapy*; D008875:Middle Aged; D000072078:Positron Emission Tomography Computed Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D000911:Antibodies, Monoclonal; D003287:Contrast Media; D000074324:Ipilimumab; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D007479:Iopamidol
keywords: CT; Colitis; Immunotherapy; Ipilimumab; Melanoma