Report on Slide Session, British Society for Haematology, 42nd Annual Scientific Meeting, Brighton, 2002 B. J. BAIN, D. WINFIELD, J. MURRAY, A. EDEN, E. PSIACHOU- LEONARD, M. GILLEECE, V. DEVALIA, C. HATTON, H. EAGLETON, S. RASSAN Each year, at the Annual Scientific Meeting of the British Society for Haematology, there is an educational session in which two experts discuss the morphological features of blood films or bone marrow biopsy sections from patients who have presented a diagnostic problem or who are otherwise instructive. The experts are given no informa- tion beyond the brief details provided to all participants who review the slides before the meeting. After the discussants have given their opinions, the case contributor presents further details and gives the final diagnosis. This report follows the format of the meeting so that the reader can reach a provisional diagnosis for him or herself before the definitive diagnosis is revealed. Case 1 The patient was a 57-year-old Caucasian male who presented with a 3-week history of lethargy, night sweats and weight loss. He was found to have massive hepato- splenomegaly. FBC was: WBC 195 · 10 9 /l, Hb 15 g/dl and platelet count 63 · 10 9 /l. B-cell markers were neg- ative (case contributed by Dr A. Eden, Southend). The discussant (JM) illustrated medium-sized lymphoid cells with plentiful cytoplasm, azurophilic granules, cytoplasmic vacuolation and slightly irregular nuclei with nucleoli (Figure 1). He favoured an aggressive T-cell leukaemia (Gentile et al., 1994). He felt confident in his diagnosis, as he recognized this case as a patient who had recently been published in the British Journal of Haematology (Gupta, Mills & Eden, 2001). The second discussant (DW) was left with little choice but to concur. Case 2 The patient was a 6-year-old Greek girl who presented with a 6-day history of fever. She was found to have mild cervical lymphadenopathy and the spleen was palpable 3 cm below the left costal margin. FBC was: WBC 290 · 10 9 /l, Hb 7.3 g/dl, MCV 77 fl and platelet count 307 · 10 9 /l (case contributed by Dr Elene Psiachou- Leonard, Southampton). The discussant (DW) illustrated marked leucocytosis with neutrophilia, eosinophilia, basophilia and numerous granulocyte precursors (Figure 2). Monocytes were not prominent and dysplasia was minor. He thought that there were no features to suggest that this was reactive, the presence of immature granulocytes was not compat- ible with a diagnosis of chronic neutrophilic leukaemia and the age and lack of monocytosis did not favour a diagnosis of juvenile myelomonocytic leukaemia or the monosomy 7 syndrome. He thought that, despite the child’s age, the findings were totally typical of Philadel- phia-positive chronic myeloid leukaemia. The second discussant (JM) was in complete agreement. A member of the audience commented that this type of leukaemia was in fact the most common myeloproliferative disorder Accepted for publication 5 February 2003 Correspondence: Dr B.J. Bain, Department of haematology, St Mary’s Hospital, Praed Street, London, W2 1NY, UK. E-mail: b.bain@ic.ac.uk Clin. Lab. Haem. 2003, 25, 221–226 Ó 2003 Blackwell Publishing Ltd. 221