Elevated newborn serum immunoreactive trypsinogen associated with a congenital pancreatic cyst

Abstract

Congenital abdominal cysts have a broad differential diagnosis. Pancreatic cysts are rare lesions that offer a diagnostic and surgical challenge to surgeons. We report on a case of a large left upper quadrant cyst detected in utero, which remained of unclear etiology despite cross-sectional imaging at birth. Intraoperative findings confirmed its pancreatic origin. In hindsight, a pre-operative elevated immunoreactive trypsinogen, performed as part of universal cystic fibrosis (CF) newborn screening, may have suggested the diagnosis.False-positive CF screening tests may be unnoticed by a surgical team assessing infants with an abdominal mass. As universal testing for cystic fibrosis increases in Canada and worldwide, physicians should review a patient's CF screening history. Elevated immunoreactive trypsinogen levels with normal sweat chloride and cystic fibrosis transmembrane conductance regulator (CFTR) detection tests may orient towards a pancreatic etiology when assessing a patient with a congenital abdominal cyst of unclear etiology.

Keywords

• Pancreatic cyst
• Cystic fibrosis
• Sweat chloride
• Trypsinogen
• CFTR