A 5 millimeter low-attenuation lesion indicates a questionable spot in the left lobe of the liver that is roughly the size of a pencil eraser. Because the spot is low-attenuating or not well-defined, it requires further study and testing to diagnose the cause, according to World Journal of Gastroenterology.
Lesions that are less than 1 centimeter in size are benign most of the time, explains World Journal of Gastroenterology. Lesions of this sort are found in over 20 percent of the population, the majority of which present with no symptoms at all. These types of lesions range from a simple cyst to a benign tumor of blood vessels called a hemangioma.