Do metastases metastasize?

Metastatic disease is a major cause of morbidity and mortality. However, it is not clear if all metastases originate from the primary tumour or whether metastases themselves have the capacity to metastasize. In this review, the evidence for the latter phenomenon, and its biological and clinical implications, is discussed. Copyright (C) 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley Sons, Ltd.