Liver lesions are any abnormalities found on the liver, the largest glandular organ in the human body. Consisting of two main lobes, the liver is about the size of a football and triangular in shape. The liver is vital to human life. The body can only survive a few days if the liver shuts down. The discovery of liver lesions can therefore be the cause for considerable anxiety.

Among the many causes for liver lesions are malignant tumors or benign causes such as cysts, hepatic adenoma, infectious causes, hemangiomas or focal nodular hyperplasia. Statistically, benign causes of liver lesions account for more than malignant ones. Lesions on the liver remain as they began, either benign or malignant. Benign lesions on the liver do not become malignant.

The majority of liver tumors do not cause any symptoms, and liver function continues normally. Most lesions on the liver are benign and require no treatment, but accurate identification of lesions that should be investigated by specialists is vital. Unnecessary biopsy of benign liver lesions will therefore be avoided.

About 1 percent of the population has asymptomatic simple cysts on the liver. More than 95 percent of cystic lesions of the liver are simple cysts and can be easily diagnosed by ultrasonography. About 50 percent of people with simple cysts will have at least two cysts.

The most common benign solid tumors of the liver are hemangiomas, occurring in about 3 percent of the general population. The majority of hemangiomas can be readily diagnosed by contrast-enhanced computed tomography, or CT scans. Resection is resorted to only in the presence of troublesome symptoms from large tumors, typically more than 4 inches (about 10 cm) in diameter. Hemangiomas rarely become a malignant transformation or rupture spontaneously.

Liver cell adenoma and focal nodular hyperplasia are uncommon tumors, occurring primarily in women of childbearing age. The introduction of the contraceptive pill in the 1960s saw a rise in liver cell adenoma. The reduced level of oestrogen in contemporary oral contraceptives has correlated with a reduction in the incidence of liver cell adenoma. The use of oral contraceptives has no impact on the formation of focal nodular hyperplasia, is usually asymptomatic, is not premalignant and generally does not require treatment.

A patient presenting with pain from a liver cell adenoma might have a tumor that is growing rapidly, might have an intratumor hemorrhage or can feel a mass. In a presentation of this nature, there is a 10 percent risk of rupture, and the tumor is discovered to have become a malignant transformation in 10 percent of resected specimens. Liver resection might prevent these occurrences.

The most common of the malignant liver lesions throughout the world is hepatocellular carcinoma, occurring predominantly in men in African and Asian countries. The incidence of hepatocellular carcinoma is increased in areas with high carrier rates of hepatitis B and C and in patients with hemochromatosis. The fact that within three months, a healthy liver in a fit patient can regenerate a 75 percent resection, along with technical advances in liver surgery and imaging techniques means that more patients are able to access safe and potentially curative resections for both malignant and benign liver lesions.