Benign cause of increased radiocolloid accumulation on a liver scan

Increased focal radiotracer accumulation in the /sup 99m/Tc sulfur colloid liver scan was initially described in 1972. The location and intensity of the liver scan abnormality apparently correlates well with certain types of pathologic processes. The demonstration of a focal increase in radioactivity along the inferior edge of the liver between the right and left lobes has been suggested as indicative of superior vena caval obstruction. It has been postulated that obstruction to flow in the superior vena cava leads to systemic-portal shunting via superficial thoracic and abdominal venous collaterals with resultant increased delivery and phagocytosis of radiocolloid in the liver overlying the portal vein. Our case had a static liver scan consistent with superior vena caval obstruction. A normal superior vena cava was subsequently demonstrated. The etiology of the focal increase in radioactivity seen on the scan was found to be a benign alteration in hepatic morphology