[Ischemic stroke as a presentation of essential thrombocythemia. Four case reports].

Introduction: Essential thrombocythemia (ET) is a myelodysplastic syndrome that constitutes an infrequent cause of ischemic stroke. Few clinical reports have been published describing the clinical onset of ET in the form of a vascular accident.

Case Report: We describe four cases of patients with no known haematological pathology who began with an ischemic stroke and were later diagnosed as suffering from ET, following an aetiological investigation. The patients were all young, under 45 years of age, with no significant vascular risk factors, who presented a clinical picture of ischemic stroke and platelet counts above normal values, although in two cases they were below 600 x 10(9)/L. As they progressed, their platelet counts were constantly above this threshold and a diagnosis of ET was reached.

Conclusions: Although ET is an infrequent cause of ischemic stroke, it must be taken into account even in young patients and when platelet counts do not exceed 600 x 10(9)/L. Antiplatelet drug therapy must be indicated in all cases and the clinician must evaluate the suitability of cytoreductive therapy in patients with a high risk of thrombotic event recurrence, especially if platelet counts are above 600 x 10(9)/L.