S5528 A Rare Dual Diagnosis in a Young Adult: Congenital Portal Vein Atresia With Pernicious Anemia Presenting as Pancytopenia and Varices

Introduction: In isolation, pancytopenia in young adults is an uncommon presentation that warrants a thorough workup. When coupled with gastrointestinal varices in the absence of cirrhosis or significant alcohol use, it further challenges conventional diagnostic pathways. This case highlights the complex and rare presentation of congenital portal vein atresia with associated portal hypertension (PHT) and varices, confounded by pernicious anemia. Case Description/Methods: A 31-year-old man with no significant past medical history presented following referral from his primary care physician for incidental pancytopenia. Initial labs were notable for WBC 3.56 k/uL, hemoglobin 5.7 g/dL (MCV 65.7), and platelets 134 k/uL. Iron studies revealed severe iron and vitamin B12 deficiency with positive intrinsic factor antibodies. The patient received 3 units of packed red blood cells during admission with hemoglobin improving to 8.5 g/dL. The patient underwent upper endoscopy and colonoscopy which revealed grade 3 esophageal varices and rectal varices without active bleeding. Computed tomography abdomen and pelvis showed atresia of the portal vein, diffuse varices, and mild splenomegaly. A transjugular liver biopsy showed a nearly normal liver with patchy mild sinusoidal dilation and no fibrosis. The hepatic venous pressure gradient indicated presinusoidal PHT. He was started on carvedilol for variceal prophylaxis, oral iron, vitamin B12, and vitamin D. No signs of decompensated liver disease were present. He was referred for transthoracic echocardiogram with bubble study to evaluate for associated congenital cardiac anomalies outpatient, and consideration of TIPS. Discussion: The patient was diagnosed with congenital portal vein atresia, seen in 1:50,000 asymptomatic adults. It illustrates an uncommon primary presentation of pancytopenia secondary to portal vein atresia and splenomegaly, confounded by concurrent pernicious anemia. Portal vein atresia is a rare congenital anomaly often diagnosed in childhood, usually associated with other cardiovascular abnormalities; however, it has been seen in exceedingly rare cases in surviving adults and can lead to PHT without cirrhosis. Luckily, his outpatient labs allowed for early detection, prior to physical signs or complications of severe PHT. This rare presentation challenges our physiologic understanding and treatment options for adults with isolated portal vein atresia.