We describe a case characterized by the onset of bone marrow hypoplasia. After treatment with steroid and anabolic compounds, it evolved into a myelodysplastic syndrome (MDS) as demonstrated by morphological and karyotypic analysis. Despite the dysplastic nature of the disorder, a unique feature was its association with a high platelet count. The pathogenesis of the thrombocytosis could not be clearly identified. In fact, the course of the disease was complicated by severe infections that, together with therapy, could have played some role in stimulating thrombopoiesis. However, since MDS can precede or follow a chronic myeloproliferative disease, it is also possible that the platelet elevation in our patient could have been sustained by a primitive thrombocyte disorder.