Segmental misty mesentery: analysis of CT features and primary causes.

Abstract

To review the computed tomographic (CT) features of segmental misty mesentery (SMM) in 29 patients and assess the primary causes of this CT finding. The authors analyzed the medical records and CT features of SMM in 29 patients. CT images were evaluated for the site, thickness, and vascular changes of the involved mesentery; bowel wall changes; lymphadenopathy; and the fat ring sign. The primary cause of SMM in five patients was determined at histopathologic examination, that in three patients was determined at surgical observation of the mesentery, and that in nine patients was determined on the basis of follow-up CT and clinical data. The primary cause of SMM in 12 patients was unknown. Twenty-five of the 29 patients had various underlying diseases. Fourteen (48%) patients had a malignancy: 11 had intraabdominal cancer and three had extraabdominal cancer. Jejunal mesentery was more commonly involved than was ileal mesentery (P <.05). The mean thickness of the SMM was 4.0 cm. Mesenteric vessels were dilated in 27 patients (93%): 19 with venous dilatation and eight with either arterial dilatation only or both arterial and venous dilatation. At CT, seven (24%) patients had a thickened bowel wall; nine (31%) patients, lymphadenopathy; and two (7%) patients, the fat ring sign. The primary cause of SMM was edema in eight, malignant neoplasm in four, inflammation and/or fibrosis in five, and idiopathic in 12 patients. At CT, SMM appears as a result of malignant neoplasms, inflammation, or vascular disorders.