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Essential Thrombocythaemia — RACP Adult Medicine MCQ

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ModerateHaematologyEssential ThrombocythaemiaRACP Adult Medicine

A 55-year-old woman presents with platelets 850 × 10⁹/L on routine FBE. She has erythromelalgia (burning pain and redness of fingers). JAK2 V617F is positive. Hb and WCC are normal. Bone marrow shows megakaryocyte hyperplasia with large hyperlobulated forms. There is no iron deficiency or inflammation. What is the most likely diagnosis?

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Correct answer: E — Essential thrombocythaemia

Persistent thrombocytosis (>450 × 10⁹/L) with JAK2 positivity (~60% of ET), erythromelalgia (pathognomonic for MPN-related thrombocytosis), and characteristic bone marrow (large hyperlobulated megakaryocytes) fulfils WHO 2022 criteria for ET. Risk-stratify using IPSET-Thrombosis score. Treatment: aspirin for all (unless very high platelets >1500 — acquired VWD risk); cytoreduction (hydroxyurea) for high-risk patients (age >60 or prior thrombosis).

Reference: WHO – 2022 – MPN; ELN 2024