The majority of abdominal masses in the newborn are genitourinary in origin.1 However, those masses arising from the liver or biliary tree, ie, subcapsular hematoma, choledochal cyst, hemangioendothelioma, and hepatoma, are also part of the differential diagnosis.2
We describe three premature neonates who had palpable right upper-quadrant masses. In each case, the mass was shown by ultrasonography to be a distended but otherwise normal gallbladder.
Report of Cases.—Case 1.—A 2,030-g male infant born at 34 weeks' gestation was admitted with severe respiratory distress syndrome and required mechanical ventilation. An exchange transfusion for hyperbilirubinemia was performed on the fifth hospital day; the total serum bilirubin concentration at that time was 17.6 mg/dL, with a direct fraction of 1.6 mg/dL. A firm, movable right upper-quadrant mass was palpated at 5 days of age, just before the exchange transfusion. The infant had not been fed enterally before this time.