Sclerosing mesenteritis is part of a spectrum (including mesenteric lipodystrophy and mesenteric panniculitis) of idiopathic primary inflammatory and fibrotic processes that affect the mesentery. Pathophysiologically, these processes may affect the integrity of the gastrointestinal lumen and mesenteric vessels by a mass effect. These are uncommon disorders that predominantly affect men between the fifth and seventh decades of life and may result in a variety of gastrointestinal and systemic manifestations, including abdominal pain, nausea and vomiting, diarrhea, weight loss, and fever [1-4].
The nomenclature of this pathophysiologic continuum has been beset with confusion since the term "retractile mesenteritis" was proposed in 1924 . Subsequently (in the 1960s) a report described seven patients with recurring episodes of moderate to severe abdominal pain, intermittent nausea, fever, and malaise, and, in over half of cases, a palpable abdominal mass [6,7]. On pathologic evaluation, patients had "extensive involvement of the mesentery of the small bowel by a chronic nonspecific inflammation." On the basis of these findings, the condition was called mesenteric panniculitis.
Since these initial descriptions, other terms have been applied to describe processes with overlapping clinical and histologic features, including mesenteric lipodystrophy and sclerosing mesenteritis (table 1). Most patients have a range of pathologic findings, although usually one feature predominates at a given time. Histologic progression has only rarely been documented . It is quite likely that these features represent different points in the natural history of the underlying process, with adipocyte necrosis (mesenteric lipodystrophy) evolving into a chronic inflammatory state (mesenteric panniculitis), and finally to fibrosis (sclerosing mesenteritis). Although consensus has not been achieved on the classification of these disorders, sclerosing mesenteritis may be the best umbrella term .
This topic review will provide an overview of sclerosing mesenteritis. Unless specifically noted, the same discussion applies to the entities designated mesenteric lipodystrophy and mesenteric panniculitis .
The epidemiology of sclerosing mesenteritis is unknown. An autopsy series reported a prevalence of one percent, suggesting that many cases are undiagnosed during life . A more recent report described a prevalence of 0.6 percent in over 7,000 abdominal computed tomography examinations . Although mesenteric panniculitis has been reported in persons as young as three years of age, most patients were white, and in the fifth to seventh decades of life, with a median age of 65 years . The rarity of this entity in childhood and adolescence has been attributed to a lesser amount of mesenteric fat in comparison to adults . Most reports have found a male preponderance, on the order of 2:1, although female predominance (65 percent) was described in at least one study [8,11].