Portal cavernoma in type 1 neurofibromatosis: A fortuitous or causal association?

Abstract

Neurofibromatosis type 1 (NF‐1) is a multisystem genetic disorder affecting the NF1 tumor suppressor gene. Patients typically develop superficial (cutaneous) and internal (plexiform) neurofibromas. The latter may rarely involve the liver locating in the hilum and encasing the portal vessels, leading to portal hypertension. Vascular abnormalities (NF‐I vasculopathy) are a well‐recognized manifestation of NF‐1. Although the pathogenesis is not well‐known, NF‐1 vasculopathy involves arteries of both peripheral and cerebral territories, with venous thrombosis being exceptionally reported. Portal venous thrombosis (PVT) is the leading cause of portal hypertension in childhood and has been associated with several risk factors. Nevertheless, predisposing conditions remain unknown in more than 50% of the cases. The treatment options are limited, and its management is nonconsensual in the pediatric age. We report the case of a 9‐year‐old boy with clinically and genetically confirmed NF‐1, diagnosed with portal venous cavernoma after an episode of gastrointestinal bleeding. There were no identifiable risk factors for PVT and intrahepatic peri‐hilar plexiform neurofibroma was excluded by MRI imaging. To the best of our knowledge, this is the first report of PVT in NF‐1. We speculate that NF‐1 vasculopathy may have been a pathogenic factor, or instead, it was a fortuitous association.