Ultrasonography is the modality of choice for demonstrating many cystic structures within the body. However nuclear medicine is often able to demonstrate functional disturbance where ultrasound and conventional radiography are unsuccessful. A case is presented in which a 16 day old male child presented to nuclear medicine with a right upper quadrant cyst found on ultrasound with exact location equivocal. Determining the location and nature of the cyst was essential to the treatment team for patient management. A hepatobiliary study was performed and evidence of a choledochal cyst was found. In partnership with ultrasound, nuclear medicine was able to identify a possibly malignant structure and consequently patient management was determined.