Introduction

‘yyto put together such apparently dissimilar diseases as chronic granulocytic leukaemia, polycythemia, myeloid metaplasia and di Guglielmo’s syndrome may conceivably be without foundation, but for the moment at least, this may prove useful and even productive. What more can one ask of a theory?’So ended the editorial entitled ‘Some Speculations on the Myeloproliferative Syndromes,’which William Dameshek published in one of the early issues of Blood in 1951. 1 He speculated that these various conditions, which he had termed ‘myeloproliferative’, were all somewhat variable manifestations of excessive proliferative activity of marrow cells, perhaps because of a thitherto undiscovered stimulus. More than half a century later, Dameshek, were he still alive, would probably have been pleased to learn that much has been learned about the cellular defects that cause these various disorders and the term he introduced, myeloproliferative, is still in daily use. It is true that we do now talk of the chronic myeloproliferative disorders (CMD), a category into which Di Guglielmo’s syndromes do not really fit, but the other haematological disorders that Dameshek grouped together do now seem to share more cellular and molecular characteristics than might have been expectedFand many of the unanswered questions in the different disorders are also very similar. It is worth noting that the 2008 World Health Organization classification scheme for myeloid neoplasms groups the chronic myeloproliferative