False positive liver scan due to a thin left hepatic lobe.

A young man with pectus excavatum and Gilbert's syndrome was found to have an abnormal hepatic photoscan, repeatedly interpreted as showing a mass lesion in the left lobe. Although his habitus suggested that it was a normal anatomic variant, numerous diagnostic procedures did not convincingly exclude disease of the liver. Peritoneoscopy confirmed that the left lobe was thin but otherwise normal. We review the causes of false positive liver scans.