This is more than likely an incidental finding of something completely harmeless, however you should get a follow up imaging of the liver to better assess it. Recommended studies include a "triple phase CT scan of the liver" and / or a "doppler ultrasound
of the liver".
Keep in mind that this is most likely bening, such as an Hemangioma
(that you probably have had since birth), or hepatic adenoma
(benign), or "FNH" (focal nodular hyperplasia
In any case, chances of something malignant are low, particularly if you don't have a history of liver disease or infections (Such as hepatitis B
Hope that helped, sincerely,