[Hairy cell leukaemia (author's transl)].

Among 12 patients with hairy cell leukaemia two died without splenectomy and two more 11 months and 7 1/2 years after the operation. In all patients removal of hypersplenism led to improvement of haematological criteria over several months up to many years. This was particularly true for platelets and granulocytes and thus for the proneness to infection and haemorrhagic diathesis. In two patients normalisation of all haematological parameters including histologically scarcely detectable hairy cells was observed. Differential diagnosis from prolymphocyte leukaemia is difficult. Nuclear morphology permits recognition of different degrees of maturation of hairy cells. In cases where tartrate resistant acid phosphatase (TRAP) cannot be demonstrated cytologically, demonstration of isoenzyme 5 is sometimes possible using gel electrophoresis. Demonstration of TRAP remains valuable for the diagnosis of hairy cell leukaemia, however only in connection with other criteria indicating this form of leukaemia.