[Morphological and functional studies in a case of primary (idiopathic) thrombocythaemia in childhood (author's transl)].

Primary (idiopathic) thrombocythaemia is a rare disease in childhood. Haemorrhagic diathesis and splenomegaly are principal findings besides thrombocytosis. The cases of a nine year old girl with thrombocyte levels between 2.8 and 4.5 X 10(6) microliter is described. The examination in light and electron microscopy revealed various morphological abnormalities in thrombocytes and megakaryocytes. Platelet function was disturbed in various degrees. The impact of functional abnormalities on the haemorrhagic diathesis is discussed. The findings in this child were compared to those of the better characterized picture of primary and secondary thrombozytosis in adulthood. Possible pathogenic relations to myeloproliferative diseases are also discussed.