A general review of anomalies of hepatic morphology and their clinical implications.

Anomalies of hepatic morphology, as opposed to anatomical variations, are rare. Nevertheless, knowledge of such anomalies is important since they do not always remain clinically latent. Four case studies of different types of anomalies encountered in surgical practice in the adult are reported herein. A general review of hepatic anomalies can be divided into two categories, i.e. anomalies due to defective development and anomalies due to excessive development of the liver. Such disturbances are sometimes associated with malformations of other structures, especially the diaphragm and suspensory apparatus of the liver. Defective development of the left lobe of the liver can lead to gastric volvulus. Conservely, defective development of the right lobe either remains clinically latent or leads to portal hypertension. Anomalies related to excessive development of the liver lead to formation of accessory lobes annexed to the liver. Despite their diversity of shape, size and location, such accessory lobes have common features allowing them to be considered as an entity. In most cases the accessory lobe is found in the infra-hepatic position. Riedel's lobe is the best known example of a sessile accessory lobe. Accessory lobes may also stimulate tumor. In cases where the accessory lobe has a pedicle, torsion is a common event leading to discovery of the abnormal mass. The origin of the anomalies of hepatic morphology occurring in the course of organogenesis remains to be elucidated. The use of ultrasonography should now allow identification of such anomalies prior to the occurrence of an acute complication and in the future to possibly detect them in the fetus.