Idiopathic Myointimal Hyperplasia of Mesenteric Veins: A Challenging Diagnosis with Dreadful Complications in Geriatric Population

INTRODUCTION Idiopathic myointimal hyperplasia of mesenteric vein (IMMHV) is an uncommon cause of ischaemic bowel ulceration.[1] It is a rare condition characterised by smooth muscle proliferation of tunica intima of small- and medium-sized veins of the mesentery. It has been reported in all the groups with peak incidence in middle age. Patients commonly present with protracted complaints of abdominal pain, constipation or diarrhoea and rectal bleeding. On initial evaluation, this rare entity is always misdiagnosed as inflammatory bowel disease (IBD).[2] As a result, patients suffer from recurrent episodes of bleeding per rectum, which often lead to complications such as perforation, necrosis, infection and shock.[3] Surgical resection on the involved segment is the only way of diagnosis and treatment. We hereby report a case of a geriatric male who presented with multiple episodes of profuse bleeding and complications. This case emphasises this rare but important diagnosis of IMHMV in geriatric population. CASE REPORT An 81-year-old male patient presented to the emergency department of our tertiary care centre with complaints of bleeding per rectum. The patient had several episodes of haematochezia and melena in the last 8 months and a history of multiple colonoscopies, capsule endoscopy and multiple transfusions. The patient had a past history of chronic kidney disease Stage 5 and was on maintenance haemodialy sis with controlled diabetes mellitus type II, hypertension and coronary artery disease with stent placement. During the present admission, triple-phase computed tomography revealed hyperdense contents in the colon, representing the blood clots. There was no evidence of active vascular leak or extravasation and only a few small diverticuli and calcified appendices epiploicae were noted. Colonoscopy showed few intraluminal blood clots only. The patient had another episode of profuse bleeding for which exploration laparotomy with intraoperative enteroscopy was performed. Transillumination revealed a group of abnormal vessels within the jejunal mesentery. Segment having abnormal vessels was resected with end-to-end anastomosis. On gross inspection, mucosa revealed several small longitudinal ulcers of reddish-brown colour with punched-out borders, varying from 0.5 to 1.5 cm in length [Figure 1]. There was thinning of underlying wall. The rest of the mucosa was grossly unremarkable. Representative sections from the ulcers and entire length of the attached mesentery were processed. Microscopic examination revealed loss of surface villi with necrosis and sloughing of surface epithelium, fibrin accumulation and intramucosal haemorrhages with withering of underlying crypts. Mucosal capillaries were dilated and congested [Figure 2]. Sections from attached mesentery showed marked myointimal hyperplasia of mesenteric veins with obliteration of vascular lumina [Figure 3]. This was highlighted by Verhoeff’s van Gieson (VVG) stain and by immunohistochemistry for smooth muscle actin (SMA). There was no evidence of activity, chronicity, granulomatous or neoplastic pathology.Figure 1: Small longitudinal ulcers of reddish-brown colour with punched-out borders and clean base (black arrows)Figure 2: Withering and loss of surface villi with necrosis and sloughing of surface epithelium, fibrin accumulation and intramucosal haemorrhages with loss of underlying cryptsFigure 3: Myointimal hyperplasia of mesenteric veins with obliteration of vascular lumina (a and b) highlighted on Verhoeff’s van Gieson staining (c and d)DISCUSSION Idiopathic myointimal hyperplasia is a rare non-thrombotic, non-inflammatory vascular cause of intestinal ischaemia which clinically mimics IBD. It was first described in 1991 by Genta and Haggitt in a case series of 4 male patients with a variable age range from 25 years to 67 years.[4] To the best of our knowledge, only 50 cases have been reported in the literature.[5] This is a fairly underdiagnosed condition given that pre-operative biopsies show non-specific findings, and definitive diagnosis is made on histopathological review of resected specimens.[6] The most common site involved in this disease is the rectosigmoid colon. Only few cases have been reported in small bowel and ours is one such case showing involvement of the jejunum. Although the first case of jejunal involvement showed only one vein rather than multiple with eccentric luminal occlusion, our case clearly demonstrated marked myointimal hyperplasia of multiple mesenteric veins with obliteration of vascular lumina.[7,8] Typically, the disease was considered to involve rectosigmoid. However, the current literature shows the involvement of proximal segments of the colon, as well as the ileum and jejunum. Initially, it was observed in young age, subsequent cases were reported in the middle to older age group with median age of presentation as 59 years. Clinical symptoms are non-specific such as bloody diarrhoea, abdominal pain and weight loss. Colonoscopic findings usually include friable mucosa along with erythematous, oedematous and ulcerated walls.[9] Due to these non-specific clinical symptoms and endoscopic findings, it is often misdiagnosed as IBD. The biopsy findings show ischaemic, congested mucosa with increased vascularized mucosal capillaries in the lamina propria and a lack of histological features for IBD. Since the mesenteric veins have an extramural location, myointimal hyperplasia of the mesenteric veins will not be seen on the mucosal biopsy, hence eluding the correct diagnosis.[8,9] The characteristic histopathological features include arterial-sparing intimal smooth muscle hyperplasia of small- and medium-sized mesenteric veins, which can be highlighted on immunohistochemistry for SMA. To further support the diagnosis, special stain for elastin like VVG that highlights the elastic laminae in arteries which is absent in the affected veins, can also be performed.[10] Luminal occlusion of the veins causes ischaemic injury to the mucosa resulting in ulceration, sloughing and necrosis of the surface epithelium, fibrin accumulation, intramucosal haemorrhages and superficial withering of crypts. In later stages, hyalinisation and fibrosis of the lamina propria and/or submucosa ensues.[6] Chronic inflammation is always absent differentiating it from a similar disease ‘mesenteric inflammatory veno-occlusive disease (MIVOD)’. MIVOD is another mimicker of IBD which is a disease of only small and medium venules, sparing the arterial system similar to IMHMV. However, the major difference between them is the presence of vasculitis in MIVOD with no skin or systemic involvement. Both these conditions are extremely rare and more cases need to be accumulated to ascertain whether they are simply different spectrums of the same disorder or separate disease processes.[11,12] The underlying pathophysiology of IMHMV is poorly understood. It has been reported that the histopathologic changes seen in IMHMV patients resemble those seen in explants with failed saphenous vein grafts from coronary artery bypass specimens that stain positive for SMA and collagen type IV.[13] Furthermore, stenotic arteriovenous fistulas in dialysis patients suggest an ‘arterialisation’ of veins due to increased intraluminal pressure.[14] Some researchers have proposed that increased mobility of the colonic segment renders it susceptible to traumatic injury secondary to torsion, volvulus, leading to the formation of an arteriovenous fistula and ultimately intimal hyperplasia of the mesenteric veins.[15] However, this theory fails to justify the occurrence of IMHMV in other parts of the intestine. Since no theory provides a clear insight into the actual pathogenesis, a further detailed study is mandated. Treatment for IMHMV patients is limited to surgical resection of the involved segment. Follow-up of up to 7 years has been reported without recurrence.[15] CONCLUSION IMMHV is a rare but important cause of non-thrombotic occlusion of vessels resulting in ischaemic bowel disease. Patients commonly present with bloody diarrhoea and abdominal pain. Diagnosis of IMHMV should be kept in differentials of refractory cases of IBD in middle to elderly age group. Delay in diagnosis can have significant morbidity and mortality secondary to severe blood loss. Surgical resection is the only method for accurate diagnosis and therapeutic modality without any recurrence. Awareness amongst the clinicians, regarding this entity especially when present in the elderly population, plays a key role in its timely management and prevention of complications. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest. Declaration of generative AI and AI-assisted technologies in the writing process No AI tools have been used in the process at any step.