[Benign liver tumors]

With widespread use of ultrasonography, fortuitous discovery of benign tumors of the liver raises the question of surgical management in a large number of young subjects. In order to obtain certain diagnosis and determine appropriate management, avoiding unnecessary surgery for asymtomatic tumors with a benign evolution or inversely delaying surgical treatment of malign lesions, the surgeon must be aware of the different features of benign tumors, their expected course, and the capacity of imaging techniques to provide positive diagnosis.

The most frequent benign tumors found in the liver are hemangiomas or angiomas. Lesions measuring less than 3 cm are often fortuitous discoveries at ultrasonography,: a typical homogeneous hyperechogenic zone is sufficient for diagnosis. There are two situations where diagnosis can be difficult: atypical hypoechogenic or large remodeled lesions, hepatopathy in the context of a malignant disease. Certain diagnosis can generally be achieved with MRI. Cystic lesions of the liver are generally biliary cysts. Ultrasonography is the examination of choice and is usually sufficient for diagnosis. In certain cases there is a differential diagnosis with a young hydatid cyst or a cystadenoma although cystadenomas are very rare tumors usually observed in symptomatic middle-aged women. In case of atypical images, cystic or necrotic malignant tumor should also be entertained as a possible diagnosis. Liver cell tumors include adenomas and focal nodular hyperplasia (FNH). Adenomas related to estrogen-progestogen treatment can lead to two potentially fatal complications (intratumor or intraperitonial hemorrhage or more rarely degeneration to hepatocellular carcinoma), justifying systematic resection. FNH is on the contrary ten times more frequent than adenoma; observed independently of hormone replacement therapy, it does not lead to complications and does not require treatment. It is crucial to establish the diagnosis of noninvasive FNH in order to avoid unnecessary surgery. MRI provides 80% and 95% specificity. If the imaging work-up evidences an atypical FNH and/or a non-tumor anomaly, histological proof is needed. As the performance and risk of percutaneous biopsy remain to be assessed, we prefer laparoscopic large needle biopsy with extemporaneous pathology examination. Imaging cannot provide positive diagnosis of adenoma.

The rule is abstention from surgery for confirmed diagnosis of angioma, biliary cyst or asymptomatic FNH, irrespective of the size. For symptomatic patients, it is essential to establish positive diagnosis initially and determine the relationship between the signs and symptoms and the tumor before deciding on adapted surgery (fenestration, enucleation, hepatectomy). Surgery may be necessary for cystadenomas, adenomas or cases of doubtful diagnosis, keeping in mind the risk of morbidity and mortality associated with hepatic surgery for benign tumors.