Isolated visceral small artery fibromuscular hyperplasia-induced ischemic colitis mimicking inflammatory bowel disease

Mesenteric Arteriovenous Dysplasia/Vasculopathy Is Distinct From Fibromuscular Dysplasia

Fibromuscular dysplasia (FMD) is a noninflammatory, nonatherosclerotic vasculopathy that usually affects the carotid and renal arteries. We have observed FMD-like vascular changes in specimens resected for ischemia or Crohn's disease (CD). On the basis of a systematic clinicopathologic review of these 11 cases identified between 1982 and 2014, we describe a distinct mesenteric vasculopathy that involves both arteries and veins [mesenteric arteriovenous dysplasia/vasculopathy (MAVD/V)] and is characterized by (1) concentric/eccentric smooth muscle collarette around the tunica media of both the artery and the vein in ≥2 foci, (2) varying degrees of intimal and medial hyperplasia and adventitial fibrosis, and (3) lack of inflammation or thrombi. MAVD/V cases were clinically diagnosed as CD (45%), mass/lesion (27%), ischemia (9%), obstruction (9%), or rectal prolapse (9%). Abdominal pain for >1 year was the most common symptom. Most patients were women (M:F=1:2.7; mean age, 63 y). Mucosal changes mimicking CD, such as architectural distortion (55%), multifocal ulcers (73%), and pyloric gland metaplasia (64%), were common; however, no granulomas or transmural lymphoid aggregates were identified. Ischemic pattern of injury was seen in 4 cases. Upon follow-up (mean, 31.2 mo), 8 patients were found to be asymptomatic, 2 had died of unrelated causes, and 1 was lost to follow-up. We propose the name MAVD/V for a distinct noninflammatory, nonatherosclerotic, localized form of mesenteric vasculopathy that involves both arteries and veins, distinct from FMD. Unlike FMD, surgical resection appears to be curative, with a favorable clinical outcome. Awareness of this vascular entity is important as patients may be potentially misdiagnosed as having CD and ischemic bowel disease.

Identification of the distinguishing features of Crohn's disease and ischemic colitis using computed tomographic enterography

Background and aims: The differential diagnosis between Crohn’s disease (CD) and ischemic colitis (ISC) is important as their clinical management is different. ISC can easily be misdiagnosed as CD, especially in elderly populations. The distinctive radiographic features of the two disease entities have not been investigated. The aim of this study is to assess the utility of computed tomographic enterography (CTE) in the differential diagnosis between CD and ISC.

Methods: Patients with confirmed CD and ISC were identified through an electronic medical record search of the Cleveland Clinic Foundation. Patients who had undergone CTE, with or without concurrent colonoscopy and histopathological specimens, were included in this study. CTE images were blindly re-reviewed by an expert gastrointestinal radiologist. The sensitivities, specificities, accuracies and positive and negative predictive values for each of the CTE findings in differentiating CD from ISC were estimated. Kappa coefficients (κ) were calculated to measure diagnosis agreement between CTE and the reference standard.

Results: A total of 34 eligible patients were included in this study with 17 having CD and 17 having ISC. In differentiating CD from ISC, the presence of mucosal hyperenhancement and absence of the “target sign” on CTE showed a sensitivity of 100% each for CD, while the two radiographic features yielded a low specificity of 35.3% and 76.5%, respectively. The presence of stricture had a lower sensitivity of 64.7% for the detection of CD but had a high specificity of 100%. In distinguishing CD from ISC, the accuracy of presence of mucosal hyperenhancement, stricture and absence of target sign were 67.7%, 82.4% and 88.2%, respectively. The combination of the presence of mucosal hyperenhancement and the absence of the target sign achieved an accuracy of 100% for distinguishing CD from ISC. There was a good correlation between CTE and the reference standard for distinguishing CD from ISC (κ = 0.882).

Conclusions: CTE appeared to be clinically useful in distinguishing CD from ISC.

Idiopathic myointimal hyperplasia of mesenteric veins and pneumatosis intestinalis: a previously unreported association

Idiopathic myointimal hyperplasia of mesenteric veins is a very rare disease occurring in young male patients, with no more than eight cases reported in the world literature. It causes venous ischemia in the sigmoid colon and rectum that clinically resembles inflammatory bowel disease. Pneumatosis intestinalis is also a rare condition usually associated to a wide range of diseases including bowel ischemia. We herein report on a case of pneumatosis intestinalis associated to idiopathic myointimal hyperplasia of mesenteric veins. To our knowledge, this is the first report of such an association, and the first one of idiopathic myointimal hyperplasia of mesenteric veins occurring in a female patient as well.

Ischemic colitis

Ischemic colitis is the most common form of ischemic enteropathy and occurs more frequently in elderly people. Although the etiology of ischemic colitis is diverse, the most common cause is acute, self-limited disruption of blood supply to the intestine. The typical clinical symptoms of ischemic colitis are minor abdominal pain and mild muscular tension of the affected colon segment. Hematochezia is very common, however, massive hemorrhage that can affect hemodynamics is not frequent. If the lesion is located in the mucous layer or submucosal layer, the disease is often transient and self-limited. Acute ischemic colitis with transmural infarction may lead to colonic necrosis and even death. Colonoscopy and biopsy are the gold standard for diagnosis of the disease. Most patients with ischemic colitis improve after conservative treatment in one or two days. Approximately 20% of patients may deteriorate to develop peritonitis and need surgical treatment.

Focal myointimal hyperplasia of mesenteric veins is associated with previous trauma in surgical specimens

Idiopathic myointimal hyperplasia of mesenteric veins (IMHMV) is a rare and poorly understood disease that occurs in the rectosigmoid colon of predominantly young, previously healthy, male patients. This disease is often confused with chronic idiopathic inflammatory bowel disease clinically, and pathologists may miss the diagnosis unless elastin stains are performed because diseased veins may readily be mistaken for arteries. The etiology of IMHMV is unclear, but a traumatic pathomechanism resulting in arterialization of the veins has been proposed. Review of bowel resection specimens (n=68) for non-neoplastic disease within a 1-year period in patients younger than 50 years of age revealed 10 cases with focal mesenteric vein myointimal hyperplasia. Significantly more cases with focal myointimal hyperplasia of mesenteric veins (MHMV) were associated with pre-resection trauma to the involved bowel segment (5/11 vs. 5/57; p=0.0016). A significant association of MHMV with pre-resection trauma supports the hypothesis that idiopathic myointimal hyperplasia of the mesenteric veins may be the result of trauma through torsion/stretching of the sigmoid colon and, subsequently, increased mesenteric venous pressure through arterialization.