Mesenteric panniculitis (MP) is often used as an umbrella term in radiology to describe a spectrum of incidental changes affecting the adipose tissue of the mesentery. Although initially considered a rare entity [1], the prevalence of MP is much higher than previously reported, likely because of the increased use of high-resolution computed tomography (CT) for clinical work-ups [2]. Several terms such as “misty mesentery”, “liposclerotic mesenteritis”, and “mesenteric lipodystrophy” have been reported in the literature to describe the same range of findings [3], [4], [5]. Although considered a radiological entity encompassing a broad range of non-specific mesenteric disorders, histopathologically, MP has been shown to correspond to a mixture of chronic mesenteric inflammation, fat necrosis, and fibrosis [6], [7], [8], [9].

The pathogenesis of the MP phenomenon is uncertain, and although presumably benign, clear management guidelines for this incidental finding are lacking. Such lack of consensus is partially due to several studies that suggested the possibility of MP being a paraneoplastic syndrome or an early-stage lymphoma [10], [11], [12], [13], [14], [15], [16]. Therefore, the authors of these studies considered the finding of MP as a reason to search for malignancy or at least to perform clinical or imaging follow-up [13,14]. For other authors, MP was an insignificant discovery that did not require any further investigation [17], [18], [19], [20]. However, most of these articles are subject to significant selection biases because they did not take into consideration the clinical context of discovery and did not report patient follow-up.

Because an association with subsequent malignancies has been reported, patients are frequently referred for follow-up imaging on multiple occasions over an extended period [21]. The precise extent to which this occurs is unknown, but anecdotal evidence suggests that it is substantial. A systematic review concluded that no study in the existing literature could determine the proportion of idiopathic MP with subsequent malignancy [22]. The prevalence of MP is 1.7% [22], so unnecessary imaging follow-up would represent a substantial burden on the healthcare system with respect to cost and overuse of imaging resources. The value of a size criterion for soft-tissue nodules remains unclear with contradictory results [10,12,23]. Some authors reported a threshold of 12 mm in patients followed for malignancy without considering any relationship with MP, while others reported no difference between patients with or without malignancy.

We hypothesized that MP should be considered a benign condition unless worrisome CT imaging features raise suspicion of an unknown underlying malignancy. Therefore, the aims of this study were to report the incidence and type of newly diagnosed malignancies in patients with MP and identify features on abdominal CT examinations of patients with MP that should raise the differential diagnosis of malignancy with mesenteric involvement.