S2753 Nodular Regenerative Hyperplasia-Induced Peristomal Variceal Bleeding: A Rare Thiopurine Side Effect

Abstract

Introduction: Azathioprine (AZA) and 6-Mercaptopurine (6-MP) are agents used to treat Inflammatory Bowel Disease (IBD). One of the rare side-effects described in cases throughout the literature is the development of Nodular Regenerative Hyperplasia (NRH) of the liver. NRH can lead to the development of non-cirrhotic portal hypertension (NCPH) which can then progress to ascites and varices. We present a patient who developed NRH from long-standing 6MP leading to peristomal variceal bleeding. Case Description/Methods: This case involves a 12 y/o male with fistulizing and stricturing Crohn’s disease, who was on 6-MP monotherapy from ages 14-18 and then restarted at age 27. At age 29, he underwent a partial colectomy with colostomy creation. Subsequently, he began to experience blood in his ostomy bag, which was later identified to be due to peristomal varices. Abdominal CT revealed lower esophageal varices and a nodular appearing liver. Liver biopsy then confirmed NRH, which had progressed to NCPH, and ultimately bleeding peristomal varices. The patient underwent a successful TIPS procedure with resolution of the varices and has not had any further bleeding. (Figure) Discussion: While there are a few cases of esophageal and gastric variceal bleeding due to NCPH secondary to thiopurine induced NRH, a case of peristomal variceal bleeding has yet to be described. NRH is a poorly understood condition that is characterized by diffuse transformation of normal liver parenchyma into small regenerative nodules with little to no fibrosis. Increased liver nodularity can cause NCPH and subsequently formation of varices throughout the GI tract. Patients with IBD on thiopurines have a cumulative incidence of NRH of 0.6% and 1.28% at 5 and 10 years, respectively1. NRH has a variable clinical presentation- from asymptomatic to severe complications of NCPH--and patients often do not present until late in the disease course. Several risk factors associated with development of NRH are male sex, stricturing and/or fistulizing disease, and history of a bowel resection. While NRH and its pursuing complications from thiopurines remains a rare entity, clinicians should be cognizant of this potential complication--particularly in those with fistulizing/stricturing disease and/or a surgical resection with an ostomy who present with gastrointestinal bleeding.Figure 1.: A – Digital subtraction angiographic (DSA) image shows catheter-directed venography of a dilated branch of the inferior mesenteric vein (IMV) that supplies a network of peristomal varices (black arrow). B - After successful creation of a transjugular intrahepatic portosystemic shunt (TIPS) with a covered stent (white arrow), a DSA image shows a plug and foam (black arrow) in the dilated IMV branch with decreased blood flow into the peristomal varices. C- Final DSA image of completion IMV venography shows absent blood flow into the dilated IMV branch and peristomal varices.