Essential thrombocythaemia first presenting as myocardial infarction in a 36-year-old male.

Essential thrombocythaemia (ET) is a myeloproliferative neoplasm where there is a clonal proliferation of thrombocytes. Whilst most often diagnosed incidentally, it can uncommonly present with arterial thrombosis. This is a case presentation of a 36-year-old male who was diagnosed with ET following myocardial infarction caused by multiple thrombotic emboli. The patient was initially misdiagnosed with viral myopericarditis based on an atypical history of chest pain with a viral prodrome. Reattendance a month later with further chest pain, dynamically raised troponin and ECG changes raised suspicions of ACS. Analysis of blood markers from both admissions showed consistently elevated platelet counts. A CMR scan revealed focal ischaemic scars in multiple cardiac segments consistent with an acute coronary event or coronary embolisation. A subsequent coronary angiography demonstrated minimal coronary artery disease. JAK2 gene V617F mutation was detected, confirming ET. The patient was commenced on pegylated interferon-alpha and dual antiplatelet therapy, and discharged with follow-up.