Unusual liver variant mimicking a retroperitoneal mass. CT scan appearance and diagnosis by SPECT imaging.

An unusual posterior extension of the right lobe of the liver mimicked a retroperitoneal mass on CT scanning. Tc-99m SC SPECT imaging documented normal liver uptake within the suspected mass, proving that it was an anomalous extension of the right lobe of the liver rather than a pathologic lesion. This unusual liver variant is not believed to have been reported previously.