Myointimal hyperplasia of mesenteric vein- an experience in a tertiary care centre

Background: Idiopathic myointimal hyperplasia of mesenteric vein (IMHMV) is an extremely rare cause of venous mesenteric ischemia. It is defi ned as non-thrombotic occlusion of the mesenteric veins secondary to myointimal hyperplasia. IMHMV is a poorly understood condition involving the rectosigmoid colon predominantly young previously healthy male individuals Purpose to analyze surgically resected bowel specimens reported routinely as intestinal ischemia for the presence of features of IMHMV. There were 30 IMHMV of 118 cases that had been reported as intestinal ischemia. Results: Clinical and laboratory fi ndings in these 30 cases were re-evaluated. Mean age was 41.83±21.67 years and male female ratio was 5:1. Common presenting symptoms were abdominal pain (93.3%), diarrhoea (70%) and rectal bleeding (40%). Left colon was commonest site of involvement followed by right colon and ileum. Unique histological features observed were variable grades of fi brosis with subserosal and submucosal small to medium size veins showing myointimal proliferation. Thirteen of these 30 patients had associated intestinal stress conditions like strictures, torsions, volvulus and intussusceptions. Majority of these patients were investigated further for hypercoagulable states and were documented to be negative. Conclusion: IMHMV is a selfl imited condition where surgical resection of the affected segment is suffi cient for a defi nitive treatment and needs to be recognized to avoid further unwarranted “management”. Research Article Myointimal hyperplasia of mesenteric veinan experience in a tertiary care centre Rama Kumari Badyal, Jasmina Ahluwalia* and Kim Vaiphei Departments of Histopathology and Hematology*, Postgraduate Institute of Medical Sciences and Research, Chandigarh, India Dates: Received: 01 August, 2017; Accepted: 01 September, 2017; Published: 04 September, 2017 *Corresponding authors: Kim Vaiphei, Professor, Department of Histopathology, Anand Block, Postgraduate Institute of Medical Sciences and Research, Chandigarh, India, Pin – 160012, Tel: +91 9815912943; Fax: 0172 2744401; Email:


Background
Idiopathic myointimal hyperplasia of mesenteric vein (IMHMV) is a rare disease described by Genta and Haggitt in 1991 [1]. It is a poorly understood disease frequently involving rectosigmoid usually in healthy young males. Often it is mistaken for infl ammatory bowel disease (IBD) or mesenteric infl ammatory veno-occlusive disorder (MIVOD) [2]. IMHMV usually presents with rectal bleeding or bloody stool resembling IBD. The diagnosis is established at histopathological examination of the surgical resected specimen in which the veins show intimal smooth muscle proliferation with normal accompanying arteries. IMHMV has been described mainly in the territory of inferior mesenteric venous drainage [3]. It has a benign clinical course and does not relapse after surgical resection of the affected intestinal segment [4]. Incidence of IMHMV is not known, likely to be under recognized and is important to differentiate from other conditions like IBD and intestinal tuberculosis. The present study was undertaken to determine prevalence of IMHMV in a tertiary care centre in surgical resected specimens retrospectively in cases that had been reported as ischemic enterocolitis, and to evaluate clinical profi les and laboratory parameters.

Material and Methods
We retrospectively evaluated cases that had been routinely reported as intestinal ischemia, by examining the hematoxylin and eosin (H&E) stained slides. We studied the major veins and arteries and the smaller sub-mucosal vessels. We also evaluated the clinical profi les and the laboratory parameters form the patient records. There were 118 cases which had been reported as ischemic enterocolitis over fi ve years i.e. from 2011 to 2016. Site wise distributions of these 118 cases included left (34 cases) and right (48 cases) segmental colonic resections, total colectomy (10 cases), segmental resections of small bowel (20 cases), and resection of colostomy site (6 cases).
In the present study the term pre-resection trauma refers to the bowel segment that had been exposed to signifi cant mechanical pressure and stress like volvulus, intussusceptions, obstruction due to stricture (infl ammatory and/or neoplastic) to further investigation for prothrombotic state which included prothrombin time (PT), activated partial thromboplastin time (APTT), protein C (PC) and S (PS), anti-thrombin III (ATIII), Factor V Leiden mutation (FVL), anti-cardiolipin antibody (ACA) and anti-ẞ 2GP1 testing (B2GPI). Pro-thrombotic workups were carried out after a minimum gap of six weeks following the surgical procedure and four weeks after completion of oral anticoagulation therapy.   (13) Colonic diverticular disease (8) Enteric duplication cysts (4) Lower GI bleeding (18) Small and large intestinal erforations/gangrene (24) Mesenteric venous thrombosis (8) Meckel's diverticulum (5)
And the sex ratio in our study is similar to the reported series [4,11,15,17]. The common presenting symptoms in our cases were abdominal pain, diarrhoea and rectal bleeding, similar to the reported symptoms [7,[13][14][15]17,19]. In the reported series, rectosigmoid region has been cited as the commonest site of involvement [4,11,14,16], which is similar to the present study.
Dominant involvement of rectosigmoid region by IMHMV has led to the speculation of the underlying etiology to be related to an increased mobility of this bowel segment resulting in repeated vascular trauma resulting in myointimal hyperplasia in the involved relatively hypoxic veins [2,[21][22][23].
Underlying etiology of IMHMV still remains obscure.
Abu-Alfa et al. [2], hypothesized segmental arteriovenous fi stulization secondary to torsion or stretching injury to be the underlying etiology for myointimal hyperplasia (MH) in the affected veins, as in sigmoid mesocolon which is far more mobile than other colonic segment. This hypothesis has been supported by Sherman et al. [4]. In the present study,   stage of MIVOD or enterocolic lymphocytic phlebitis, as seven of their patients who had intestinal ischemia, three showed evidence of MHMV along with active phlebitis and venulitis. They had used the termed MIVOD by hypothesizing that it might be a precursor lesion of MHMV. Small bowel IMHMV had also been reported in association with appendiceal mucocoele and pseudomyxoma peritonei [16]. We also have one patient who was treated for IPSID and had developed MH one year after completion of chemotherapy. Most reported cases of IMHMV were considered clinically to be IBD and were invariably treated with steroids and other specifi c anti-infl ammatory drugs which might result in reduction of infl ammation [17,[24][25][26]. Potential overlap between the two disorders is highlighted in a reported case as enterocolic lymphocytic phlebitis or mesenteric infl ammatory veno-occlusive disorder [25]. In all documented cases of IMHMV, the diagnoses had been established on histological examination of the surgical resection specimens as the diagnostic features were not obvious in mucosal biopsies and in none of these reports and our cases did not have any associated mucosal changes of IBD [17,18]. Recently reported fi ndings of subtle angiographic changes may have a supportive role in the diagnosis of IMHMV [26].