Adenoma of the liver, mixed type (hamartoma).Report of two cases

H E number of reported cases of primary benign liver tumors is extremely small, and relatively few of these have been considered benign adenoma, mixed type or hamartoma.The term "hamartoma" was first coined in 1904 by Albrecht to define tumor-like malformations in which there is demonstrable an abnormal mixing of the normal constituents of the organ in which they appear, whether it be in the amount, or arrangement, or degree of differentiation or maturation, or in all these respects.Although the precise differences between neoplasms and hamartomas are obscure, hamartomas are generally considered non-neoplastic, lacking the property of limitless growth.Witwicky is credited with first having proposed the following classification of primary benign liver tumors: (1) adenomas derived from liver cells; (2) cholangiomas derived from bile ducts; and (3) adenomas, mixed type, derived from liver cells and bile ducts.These tumors may be single or multiple; they are generally single in otherwise normal livers, and multiple in cirrhotic livers.Neither Witwicky, however, nor later German authors who discussed adenomas of the liver give examples of the mixed type.Ewing,while listing the mixed tumors in his classification, states that they must be accepted with caution, that their histogenesis is not clear, and that they probably arise in extensively cirrhotic organs.