Diagnosis of Essential Thrombocythemia (ET): Bone Marrow Findings

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The page below is a sample from the LabCE course Myeloproliferative Neoplasms. Access the complete course and earn ASCLS P.A.C.E.-approved continuing education credits by subscribing online.

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Diagnosis of Essential Thrombocythemia (ET): Bone Marrow Findings

ET is usually characterized by hypercellular bone marrow, including increased megakaryocytes. Other features include giant megakaryocytes, clusters of megakaryocytes, or other dysplastic megakaryocytic changes. Bone marrow reticulin is usually increased, although collagen fibrosis is rare. The image is a bone marrow biopsy showing megakaryocytic hyperplasia and clustering. These features are consistent with ET. The arrows in the image point to a cluster of megakaryocytes and an abnormal, multi-lobulated megakaryocyte.
Secondary or reactive thrombocytosis, polycythemia vera, and other disorders can have similar features. Therefore, additional criteria must be considered along with bone marrow findings when diagnosing ET.

BM biopsy showing megakaryocytic hyperplasia and clustering consistent with essential thrombocythemia. Used with permission from: S G Holtan, J D Hoyer and F K Buadi.