[Anaplastic large-cell lymphoma. Conceptual and diagnostic assessment]

The authors critically review the concept of anaplastic large cell lymphoma (ALCL). In particular, they provide the guidelines to the morphologic identification of the four main varieties of the tumour: common, giant-cell-rich, lympho-histiocytic, and Hodgkin's-like. The phenotypic and molecular characteristics of the neoplasm are discussed with special emphasis to those which can assist in the differential diagnosis between ALCL and Hodgkin's disease. Finally, the clinical features are presented along with the results obtained in the course of long-term prospective therapeutical trials.