Mesenteric panniculitis part 1: mdct - pictorial review

Abstract

Mesenteric panniculitis is an uncommon benign inflammatory condition of unknown etiology that involves the adipose tissue of the mesentery and for which an extremely varied terminology has been used, causing considerable confusion. It can be evaluated as a single disease with two pathological subgroups: Mesenteric Panniculitis (MP), representing the very large major subgroup where inflammation and fat necrosis predominate and Retractile Mesenteritis (RM), much rarely found, where fibrosis and retraction predominate. In histo-pathological terms the preferred terminology is sclerosing mesenteritis. We hereby extensively illustrate the characteristic MDCT findings of MP through pictures selected among a collection of cases constituted over a 5-year period. All patients were scanned with 64-row MDCT equipment. We also review the literature and discuss the differential diagnosis. The radiological diagnosis of MP was based on classical CT signs described in the literature and comprising: the presence of a well-defined "mass effect" on neighbouring structures (sign 1) constituted by mesenteric fat tissue of inhomogeneous higher attenuation than adjacent retroperitoneal or mesocolonic fat (sign 2) and containing small soft tissue nodes (sign 3). It may typically be surrounded by a hypoattenuated fatty "halo sign" (sign 4) and an hyperattenuating pseudocapsule may also surround the all entity (sign 5). The last two signs are considered inconstant but very specific. The absence of histological verification constitutes the weakness of our study. The differential diagnosis of MP is extensive and includes all disorders that can affect the mesentery. The most common ones are lymphoma, well-differentiated liposarcoma, peritoneal carcinomatosis, carcinoid tumor, retroperitoneal fibrosis, lipoma, mesenteric desmoid tumor, mesenteric inflammatory pseudotumor, mesenteric fibromatosis and mesenteric edema. PET/CT is proved useful to correctly exclude mesenteric tumoral involvement in patients presenting with typical MP. The course of MP is favorable in most cases and progression of MP to retractile mesenteritis not only appears very being rare but finally remains doubtful.

Mesenteric panniculitis part 2: prevalence and natural course: mdct prospective study

“…In histo-pathological terms, the preferred terminology is Sclerosing Mesenteritis (1,3,(7)(8)(9). It represents the more accurate term because of Classically on CT, MP appears as a mass of increased-attenuation mesenteric fat containing small softtissue nodes, with a maximal transverse diameter directed toward the left abdomen consistent with the orientation of the jejunal mesentery.…”

“…other mesenteric diseases (1,4,6,(12)(13)(14)(15): the presence of a tumoral pseudocapsule (found in up to 60% of MP reported cases) and the "fat ring" sign of hypodense fatty halo surrounding mesenteric nodules and vessels (seen in up to 75% of reported cases) (1, 6, 8, 16-18) (Fig. 1).…”

“…1). The overall prevalence of MP in abdominal CT examinations has previously been estimated at approximately 0.6%, commonly appearing as an incidental finding, mostly in middle or late adulthood (1,4,8,19). It is our opinion that this prevalence has probably been extremely underestimated when compared with the results of our prospective study which shows a mean prevalence of 7,83% when at least 3 CT signs are found (group 1) and still of 3,42% when all five CT signs are considered (group 2) including the "halo sign" and the presence of a "pseudocapsule" .…”

A case of symptomatic mesenteric panniculitis presenting with unusual positive FDG PET/CT nodular components: an atypical imaging strategy with histopathologic correlation.

“…The radiological CT diagnosis of MP is classically based on typical if not pathognomonic features clearly described and documented in the literature (1)(2)(3)(4)(5)(6). They comprise the presence of a well-defined "mass effect" on neighboring structures (sign 1) constituted by mesenteric fat tissue of inhomogeneous higher attenuation than adjacent retro peritoneal or mesocolonic fat (sign 2) and containing small soft tissue nodules (sign 3).…”

“…In a recent couple of papers published in volume 94 (2011) of JBR-BTR we successively tried to explore the typical imaging findings and to prospectively study the prevalence and natural course of MP (1,2).…”