Apport du pathologiste au diagnostic en hépatologie

Hepatic punch-biopsy (HPB) is an essential investigation for the diagnosis of most liver diseases. It refers to an invasive procedure that must be performed by a trained physician, and which is indicated following consensual decision. Echo-guided biopsies and needle punctures of nodules reduce the risk of serious complications; these remain rare. The histological analysis of a HPB necessitates a tissue fragment sufficiently long (25 mm at least), multilevel incisions, and systematic coloration of iron and collagen. A pathologist familiar with hepatic diseases examines and classifies the elementary lesions, and then elaborates an interpretation of all these lesions taking into consideration the patient's clinical, biological, and radiological data. Anatomoclinical confrontation is necessary for a good understanding of the lesions and definitive diagnosis. Immunohistochemistry is frequently used in the research context; in daily practice, it is useful for the diagnosis of poorly differentiated tumours or metastases. In most lesional syndromes, histology confirms the diagnosis, indicates the aetiology, and guides the prognosis: chronic intrahepatic cholestasis, chronic hepatitis, steatosis and alcohol-induced hepatic disease, metabolic diseases, vascular diseases with hepatic microvascular disorder, unexplained portal hypertension, and tumoural syndromes. Using evaluation scores internationally recognized (METAVIR score for viral hepatitis) allows large-scale prognostic studies and therapeutic follow-up, with histology as the gold standard. In the next future, therapeutic advances (especially antiviral agents) and new markers of hepatic lesions will probably limit the indications of biopsy to well determined pathological contexts. However, to date, biopsy remains the only investigation that allows simultaneous, complete and precise evaluation of all anatomic lesions.