Radiology of epiploic appendages: acute appendagitis, post-infarcted appendages, and imaging natural history

Our aim was to demonstrate the imaging characteristics of epiploic appendages in native, acute inflamed/ischemic and post-infarcted states through retrospective imaging analysis, with clinical and pathologic correlation, and to discuss clinical implications. Cases were gathered mostly retrospectively and reviewed for inclusion based on established diagnostic criteria. Radiology report text search was used to find cases, using terms "epiploic," "appendage," "appendagitis," and "peritoneal body." Data records included patient demographics, relevant clinical data, lesion size, location and apparent imaging composition, and the presence of change or stability in features over multiple studies. Pathologic and clinical data were sought and assessed for correlation. Imaging studies of 198 individuals were included (mean age 50, range 9-95), with a total of 228 lesions: 63 acute and 165 non-acute presentations. All included subjects had CT imaging and some had lesions visible on radiographs, MRI, PET/CT, and sonography. 23 subjects had more than one studied lesion. In addition to classic acute appendagitis, more frequently encountered are post-infarcted appendages either in situ along the colon, adhered to peritoneal or serosal surfaces, or freely mobile in the peritoneum as loose bodies. The majority of the non-acute varieties are recognizable due to peripheral calcification that develops over time following ischemic insult. Multiple cases demonstrated the imaging natural history and confirmed pathologic basis for imaging findings. In summary, acute and post-infarcted epiploic appendages have characteristic imaging appearances and natural history which should provide correct diagnosis in most cases. Incidental post-infarcted epiploica are more commonly encountered than acute presentations.