Liver nodules, usually a sign of liver disease, can be caused by certain parasitic or viral infections, immune system abnormalities, cancer and genetic conditions, according to Mayo Clinic. Contributing factors include heavy alcohol or drug use, unprotected sex, obesity, diabetes and exposure to certain chemicals.
Liver nodules are caused by cellular irregularities that are usually a sign of disease. Viral and parasitic infections are a major cause of liver disease and can be contracted through blood and semen or contaminated food and water, reports Mayo Clinic. The most common viruses that cause liver disease are hepatitis A, B and C. Certain autoimmune disorders can cause liver disease as well; in these cases, the immune system attacks the liver or biliary cells.
Bodily chemicals or substances can build up in the liver as well due to a heritable faulty gene, according to Mayo Clinic. Disease in the liver is common if the body stores too much iron (hemochromatosis), oxalate (hyperoxaluria) or copper (Wilson's disease). Nodular growths in the liver can also be a sign of cancer multiplying in the liver or bile duct. Finally, fat can accumulate in the liver and cause nodules; this is typically a result of alcohol abuse or nonalcoholic fatty liver disease.