An Unusual Lung Mass of Heterotopic Pancreatic Tissue in a Neonate With an Elevated Immunoreactive Trypsinogen on Newborn Screen.

We present a case of a neonate with tracheoesophageal fistula and esophageal atresia along with a suspicious lung mass who had a false-positive newborn screen for cystic fibrosis due to an elevated serum immunoreactive trypsinogen with an additionally elevated serum lipase. The infant's lung mass was found to contain heterotopic pancreatic tissue consisting of acini, ducts, and islet cells, without an associated gastrointestinal duplication cyst. This constellation of congenital abnormalities has not been described in previous literature. Also, this is the first reported case of a neonate with elevated serum pancreatic enzymes in which the underlying etiology was discovered to be heterotopic pancreas.