Massive mesenteric panniculitis due to fibromuscular dysplasia of the inferior mesenteric artery: a case report

Fibromuscular dysplasia (FMD) is a nonatheromatous, noninflammatory arterial disorder of unknown etiology resulting in vessel stenosis and/or aneurysm formation. The renal and cephalocervical (mainly carotid arteries) arterial beds are classically involved; involvement of visceral arteries is rare. Mesenteric panniculitis (MP) is an inflammatory process of mesenteric fat considered to be of unknown etiology. The majority of cases involve the small bowel mesentery; colorectal MP is rare. To our knowledge, no example of MP due to FMD has been described.

A 52 year old man presented with steadily worsening lower abdominal pain. Investigation revealed ischemic rectosigmoid mucosa associated with a large mesenteric mass of unknown nature. Angiography showed the disease was limited to the distribution of the inferior mesenteric artery. Subsequent symptoms of large bowel obstruction necessitated a left hemicolectomy. Pathologic examination showed bowel wall necrosis and massive panniculitis of the rectosigmoid due to FMD. Subsequent angiographic imaging of other vascular beds was negative.

Several features of this case are noteworthy: FMD limited to the inferior mesenteric artery has not been previously reported, FMD has not previously been implicated as a cause of MP, and the massive extent of panniculitis. An accompanying literature review of cases of visceral FMD, traditionally believed to almost exclusively affect females, highlights a greater than anticipated number of males (33 %), and a gender difference regarding concomitant involvement of cephalocervical and/or renal vascular beds (32 % in males versus 80 % in females). The latter observation may have implications regarding the value of radiologic screening of other vascular beds, particularly in asymptomatic males, in patients presenting with visceral artery FMD.