Crohn′s disease misdiagnosed as intestinal malignancy by 18F-FDG PET/CT in six patients

Objective To analyze the causes of Crohn′s disease (CD) misdiagnosed as intestinal malignancy by 18F-fluorodeoxyglucose (FDG) PET/CT. Methods The clinical and 18F-FDG PET/CT data of 70 CD patients (48 males, 22 females; average age: (32.1±16.7) years) confirmed pathologically from June 2010 to June 2016 in PET Center of Nanfang Hospital were retrospectively reviewed. Patients misdiagnosed as malignancy were selected. The locations, morphologic and metabolic features were retrospectively analyzed. Results Six of seventy CD cases were misdiagnosed as intestinal malignancy (maximum standardized uptake value (SUVmax): 7.8-29.8). Among them, 4 patients were misdiagnosed as colonic carcinoma and 2 patients were misdiagnosed as intestinal lymphoma. All the intestinal lesions in 6 patients were FDG-avid, 4 patients that were misdiagnosed as colonic carcinoma presented as localized irregular mass with extra luminal wall air bubble sign on CT. Two cases that were misdiagnosed as intestinal lymphoma presented as segmental diffusive intestinal wall thickening companied with bowel stiffness, intestinal loops enlargement and finger-pressing pattern along the surface of the intestinal mucosa on CT. Conclusions FDG-avid CD presenting as single localized irregular mass or segmental diffusive intestinal thickening can mimic intestinal malignancy. CT features are useful for differential diagnosis and reducing diagnostic errors. Key words: Crohn disease; Positron-emission tomography; Tomography, X-ray computed; Diagnostic errors; Deoxyglucose