Concurrent Management of Familial Thrombocytosis and Congenital Portal Vein Anomaly: A Rare Pediatric Case

Introduction The prevalence of familial thrombocytosis and congenital portal vein anomalies is uncertain. However, the occurrence of both diseases in a single patient is extremely rare. Thus we present a complex pediatric case involving challenging treatment and recovery due to the coexistence of these conditions. Case Presentation A 3-year-old male presented to the emergency department with hematemesis due to esophageal variceal bleeding. An abdominal ultrasound identified an anomalous two-trunk portal vein, accompanied by signs of portal hypertension, and splenomegaly. The patient was discharged with Beta-blocker therapy for portal hypertension which was ineffective. The following year, the patient underwent splenic vein embolization, transjugular intrahepatic portosystemic shunt insertion, and stenting of multiple veins. Over the next three years, splenomegaly and pancytopenia advanced and led to a splenectomy. Despite successful surgery, a subsequent rise in platelet counts (PLT) up to 2000 x 109/L led to thrombosis of mesenteric and portal veins, resulting in necrosis of the small intestine which required surgical treatment. Following resection, a 40 cm portion of a small intestine remained. Due to complications like peritonitis, colitis, coagulopathy, and septicemia, the condition of an already 7-year-old boy was critical. Genetic analysis confirmed familial thrombocytosis, identifying a mutation in the THPO gene. Despite the circumstances, the patient is stable and discharged. Discussion The portal vein is primarily formed from the vitelline and umbilical veins. Venous fenestration may result from obstruction by the common bile duct or disturbed blood flow, leading to structural changes in the vasculature and the formation of separate vessels [1]. In this case, the portal vein anomaly led to portal hypertension, with splenomegaly as the primary complication [2]. Familial thrombocytosis typically presents with persistent isolated elevation of PLT [3]. However, in cases of hypersplenism, up to 72% of the total platelet mass can be sequestered in the spleen [4]. Hence, post-splenectomy, familial thrombocytosis manifested and led to thrombus formation, as observed. Conclusions This case report of such rare conditions is the first in Lithuania and highlights the importance of a comprehensive approach to managing multiple rare diseases.