Abernethy malformation type II with nephrotic syndrome and other multisystemic presentation: an illustrative case for understanding pathogenesis of extrahepatic complication of congenital portosystemic shunt.

Abernethy malformation, an extrahepatic congenital portosystemic shunt, is more often diagnosed based on associated cardiac or pulmonary malformation. Although predominately a pediatric diagnosis, "late diagnoses" in adulthood have been reported especially in type II malformations that involve only a partial shunt of portal circulation directly into the inferior vena cava. Aside from the cardiac-related presentation, Abernethy malformation is also associated with multiple liver nodules, either benign or malignant, and pulmonary hypertension. In this report, we present immunoglobulin A glomerulonephritis with nephrotic syndrome as a hitherto unrecognized manifestation of this malformation outside the pediatric population, in a patient who also had pulmonary hypertension and multiple liver tumors. We also propose a pathogenetic basis for this multisystemic presentation that includes release into the systemic circulation of unfiltered bacteria, vasoactive substances, and immunoglobulin A-antigen complexes.