The European Bone Marrow Working Group of the European Association of Haematopathology recently concluded the tenth International Course on Bone Marrow Pathology in Greenwich, London. During the course, it became apparent that both the pace of advancement of knowledge in bone marrow pathology has never been greater and also that there remain significant “grey zones” in bone marrow pathology where there is work still to be done.

It became clear that in both myeloid and lymphoid neoplasms, areas exist where definitions are not clear, particularly with respect to progression or transformation. Traditional terminology has had to be adapted as innovative new therapies have been introduced and monitoring of disease status is now subject to molecular investigations that compel morphological methods to defer to the new techniques. New methods of analysis are moving from the research arena to the diagnostic laboratory. Apart from the ever-expanding list of new antibodies for usage in immunohistochemistry, correlation with flow cytometry and performing FISH analysis in fixed tissues will play a major component in defining and classifying bone marrow-based diseases. Mass spectrometry-based proteomics for the sub-classification of amyloid proteins is yet another example of the changing pattern of haematopathology practice. New techniques are ever more demanding of good tissue preservation, and satisfactory processing of bone marrow biopsies is critical for successful introduction of new techniques and must be awarded a higher priority. It is notable that most countries do not have quality assurance programs in place for bone marrow biopsies.

In this special issue of the journal, several authors have submitted reviews on topics covered in the course. They emphasise challenges in the areas of bone marrow pathology at the borders of established diagnostic criteria, whether driven by new insights into biology or by new therapies. Professor Bain has contributed an erudite and entertaining summary of her highlight lecture on the “Haematopathologist as Detective”. They are joined by distinguished contributions covering the utility of the bone marrow aspirates when a biopsy is performed in lymphoma cases and two reports of morphological mimics in haematopathology.

The pathology of the bone marrow has never been more interesting and the histopathologist is in an excellent position to contribute to the clinical management of patients using the latest techniques and advances in bone marrow biopsy pathology.

Jon van der Walt and Kikkeri Naresh