Sclerosing mesenteritis in small bowel transplantation: possible manifestation of acute vascular rejection

[Mesenteric panniculitis]

Mesenteric panniculitis is a condition characterized by chronic nonspecific inflammation of the mesentery. There is little and often confusing information about its characteristics and the approach to take once it has been demonstrated by an imaging test. We propose to describe the epidemiological, clinical, laboratory, radiological and pathological features of the patients with mesenteric panniculitis reported in the literature, as well as possible disorders causal or associated with mesenteric panniculitis, in the opinion of the authors of each study. Finally, we will review the different therapeutic options used and the response to them. To that end a literature search was performed from the main medical databases selecting ítems with information on these aspects. This information was collected on a database stored in SPSS software for further analysis and summary.

Updates on acute and chronic rejection in small bowel and multivisceral allografts

PURPOSE OF REVIEW

The surgical management of short bowel syndrome now includes intestinal (ITx) and multivisceral transplantation (MVTx), which has advanced and is now a sustainable option for the treatment of intestinal failure. Improvements in immunosuppressive therapies, excellence in surgical and medical management and enhanced post-transplant monitoring have all contributed to optimizing this solid organ transplant as a means of supplanting the diseased native bowel and alimentary tract with a functional alternative.

RECENT FINDINGS

Post-transplant management is a critical and challenging phase of gastrointestinal transplantation, and the transplant pathologist is an essential member of the transplant team who identifies many of the early and late complications after ITx and MVTx. Among the most injurious and common complications of ITx and MVTx is acute rejection and, to a lesser degree, chronic rejection. Both of these broad categories of rejection are principally identified by histopathological changes in the allograft; however, biomarkers and other laboratory analytes are rapidly evolving into critical ancillary tools in identifying and further characterizing the rejection process. Thus, the transplant pathologist must also be able to utilize numerous other laboratory tests and panels of molecular biomarkers that provide supplementary information to accompany the biopsy interpretation and clinical suspicion of rejection.

SUMMARY

Using biopsies and an assortment of additional approaches, the transplant pathologist is now able to provide swift and detailed information regarding the rejection process in the gastrointestinal transplant. This enables the clinical team to properly and successfully intercede, contributing to enhanced patient and graft survival.

Assessment of abnormal bowel perfusion using contrast-enhanced ultrasonography after small bowel transplantation: a case report

A 59-year-old man with short-bowel syndrome received a small bowel transplantation. Because the recipient complained of severe abdominal pain 40 hours after the surgery and was highly suspected of having mesenteric vascular thrombosis, contrast-enhanced sonography (CEUS) was performed at his bedside. CEUS demonstrated that the superior mesenteric artery was patent, but the bowel graft showed hypoenhancement, indicating severely inadequate perfusion of the graft. Due to this complication, the patient underwent an exploratory laporatomy, and the bowel graft was removed. The pathologic findings support the diagnosis of acute vascular rejection after intestinal transplantation. This case suggests that CEUS can be used to assess perfusion and vascular complications after intestinal transplantation, as it is noninvasive and easily performed at bedside.

Histological alterations in transplanted small bowel after acute antibody-mediated rejection

AIM: To observe the histopathological changes in transplanted small bowel from a patient developing acute antibody-mediated rejection (AMR) and to perform a literature review.

METHODS: The resected allograft was fixed in 10% buffered formalin, embedded in paraffin, sectioned, and stained with hematoxylin and eosin. Morphological changes in the mucosa, intestinal wall and mesentery were observed by two pathologists separately. Acute rejection, vascular lesions and related changes were assessed. Immunohistochemical staining of C4d was also performed.

RESULTS: AMR lesions were widely distributed in the allograft, involving muscular arteries, arterioles, capillaries, vasa vasorum, venules and veins. The most serious AMR was observed in arterioles located in the submucosa and vasa vasorum. Main morphological changes included fibrous necrosis of blood vessel wall, thrombosis, and leucocyte margination. Neutrophilic granulocyte infiltration was noted in the edematous interstitium surrounding the involved blood vessels, with numerous erythrocytes extravasated. The fibrocollagenous network and part of the smooth muscle cells of the outer layer of the muscularis externa showed fibrous necrosis. Foci of lysis were present in the outer layer of arteries adjacent to the involved vasa vasorum. Foci of medial necrosis in the arteries were also observed. Immunohistochemical staining showed C4d deposition in the involved blood vessels. The blood vessels in the lamina propria showed congestion and significant dilation, and thrombosis was occasionally observed. No morphological changes were found in the crypt epithelium. There was no acute rejection in the mucosa.

CONCLUSION: Fibrous necrosis of blood vessel wall and thrombosis are main morphological changes in the transplanted small bowel after severe AMR. All types of blood vessels in the allograft can be involved, but the lesion in mucosal blood vessels may not reflect the most serious injury. Therefore, early diagnosis of AMR can not rely on the biopsy of intestinal mucosa.

[Etiologic spectrum of mesenteric panniculitis: report of 7 cases]

OBJECTIVE

Mesenteric panniculitis is a rare disorder characterized by nonspecific inflammation and/or necrosis and/or fibrosis in the adipose tissue of the bowel mesentery. Its signification, primary or associated with other diseases, is a subject of controversy.

METHODS

A descriptive and retrospective study of patients with an abdominal CT examination showing features of mesenteric panniculitis and for whom biopsy with immunohistochemical examination was obtained in all cases.

RESULTS

Seven patients were enrolled (4 men and 3 women) with a median age of 62,1 years. None of the patients without an identified etiology had a history of abdominal surgery. An associated disease was identified in 4 cases: breast cancer (1), non-Hodgkin's lymphoma based on peripheric lymph nodes biopsy (2) and cryoglobulinemic vascularitis based on renal biopsy (1). In the 3 remaining cases, isolated mesenteric panniculitis was the only abnormality despite thorough imaging and pathologic investigations.

CONCLUSION

Except an obvious malignancy context or a history of abdominal surgery, a pathologic examination of the mesenteric panniculitis lesions is necessary, especially to eliminate another mesenteric disorder. Mesenteric panniculitis is often associated with lymphoma.

[Mesenteric panniculitis]

Mesenteric panniculitis also named retractile mesenterite is a rare tumor-like lesion that thickens and shortens the mesentery. It is characterized by the association of inflammation, necrosis or fibrosis involving the adipose tissue of the bowel mesentery. The pathophysiology of this disease remains unclear despite associations with inflammatory diseases or malignancies, especially lymphomas that have been described. When symptomatic, patients may present with abdominal pain, palpable abdominal mass or intestinal obstruction. The disease remains asymptomatic in 30 to 50% of cases. Abdominal CT plays an important role in suggesting the diagnosis and can be useful in distinguishing the several conditions that can mimic mesenteric panniculitis. Nevertheless, pathologic examination of surgical excisional biopsies or sometimes percutaneous biopsies remains necessary to confirm the diagnosis and exclude an underlying infection or malignancy. Medical treatment may consist of therapy with anti inflammatory or immunosuppressive agents and can be proposed in highly symptomatic diseases. Surgical treatment should be exclusively attempted when intestinal obstruction or ischemia occur. Most of the time, it consists in intestinal derivation or segmental resection because complete excision of the lesions is often not possible. Mesenteric panniculitis usually has an uneventful clinical course and resolves spontaneously in a variable delay.

Sclerosing peritonitis after intestinal transplantation in children

Long-term graft dysfunction and/or graft loss after intestinal transplantation (ITx) is a significant concern. Sclerosing peritonitis (SP) is a manifestation of chronic allograft failure and its presence may also include classic arterial obliterative arteriopathy (OA) as in chronic rejection. We describe the clinical presentation and management of SP occurring after ITx in children. Case records of 121 children undergoing ITx from 1990 to 2003 were reviewed. Three children (2.4%) presented with SP of the intestine allograft at a mean time of 6.6 yr following ITx as follows: age at Tx (yr) 8.2, and 3.7, with indication for ITx being gastroschisis in two and midgut volvulus in one patient. Type of ITx was isolated intestine in one and liver/intestine in two patients. Gross findings of SP included fibrosis/strictures; microscopically SP showed fibrosis/serositis, and fibrous adhesions; one patient had evidence of chronic allograft vasculopathy. All patients presented with clinical signs and symptoms of bowel obstruction and gastrointestinal contrast studies confirmed distal ileal obstruction (DIO). Operative findings confirmed SP and DIO in all patients; all patients were initially treated with distal segmental intestine allograft resection and lysis of the fibrous peel. All three patients recovered, although two required repeat laparotomy, there is only one long-term survival. SP after ITx may be a different manifestation of long-term intestine allograft degeneration. Surgical resection appears to offer palliation.