Evaluation of Platelet Morphology in Peripheral Blood Smear Is a Simple but Very Useful Tool for Prediction of Primary Myelofibrosis
John Wayne, Sumire Kitahara, Serhan Alkan. Cedars-Sinai Medical Center, Los Angeles, CA
Background: Primary myelofibrosis (PM) is a clonal MPN (myeloproliferative neoplasm) characterized by a proliferation of predominantly megakaryocytes and granulocytes in bone marrow that is associated with deposition of fibrous connective tissue and extramedullary hematopoiesis. The most common presentation of PM includes cytopenia or mild leukocytosis that is not specific to distinguish from other MPN and reactive processes. Although some features noted in peripheral blood smear (PBS) such as marked leukocytosis, erythrocytosis and thrombocytosis are useful for initial differential diagnostic work-up, useful clues for diagnosis of PM are limited. We evaluated platelet morphology in PBS as an aid for initial investigation of samples submitted for cytopenia and compared the findings to other mentioned conditions.
Design: A retrospective search was conducted from our case files from 2003-2011, for diagnosis made by bone marrow of normal (defined as having no myeloproliferative neoplasm), chronic myelogenous leukemia (CML), essential thrombocythemia (ET), polycythemia vera (PV) and PM. There were 19 normal non-MPN, 18 CML, 16 ET, 9 PV, and 19 cases of PM. PBS were assessed for dysmorphic features such as large platelets, hypogranular platelets (defined as <5 granules per platelet), vacuolization, and uneven distribution of granules. In order to assess platelet abnormalities, at least 20 50X oil immersion fields were evaluated and the percentage of abnormal platelets were calculated. ANOVA was used for statistical analysis.
Results: Patients with diagnosis of PM showed significantly higher occurrence platelet abnormalities compared to other MPN and samples with non-MPN lacking reticulin fibrosis. PM samples had an average of 7.8% (range:3.1-24.7%) platelet abnormalities, normal-non-MPN samples had an average of 0.2% (range:0.1-1.0%) platelet abnormalities, CML sample had an average of 0.2% (range:0.1-0.5%) platelet abnormalities, ET samples had an average of 0.4% (range:0.1-1.3%)platelet abnormalities, and PV samples had an average of 0.3% (range:0-1.0%) platelet abnormalities. ANOVA was computed and yielded a p-value of <0.001 for demonstration of platelet abnormalities noted in PM compared to other categories.
Conclusions: PM commonly demonstrates platelet abnormalities compared to normal controls and other MPN. Therefore, if there is any significant platelet abnormality noted on initial evaluation of PBS (>3% platelet abnormalities) bone marrow biopsy evaluation should be recommend with a high suspicion of PM.
Wednesday, March 21, 2012 9:30 AM
Poster Session V # 223, Wednesday Morning