A subset of patients with familial platelet disorder with propensity to myeloid
malignancy and germline RUNX1 mutation develops
hematological malignancies, often
myelodysplastic syndrome/acute myeloid leukemia, currently recognized in the 2016 WHO classification. Patients who develop
hematologic malignancies are typically young, respond poorly to conventional
therapy, and need allogeneic stem cell transplant from non-familial donors. Understanding the spectrum of bone marrow morphologic and genetic findings in these patients is critical to ensure diagnostic accuracy and develop criteria to recognize the onset of
hematologic malignancies, particularly
myelodysplastic syndrome. However, bone marrow features remain poorly characterized. To address this knowledge gap, we analyzed the clinicopathologic and genetic findings of 11 patients from 7 pedigrees. Of these, 6 patients did not develop
hematologic malignancies over a 22-month follow-up period; 5 patients developed
hematologic malignancies (3
acute myeloid leukemia; 2
myelodysplastic syndrome). All patients had
thrombocytopenia at initial presentation. All 6 patients who did not develop
hematologic malignancies showed baseline bone marrow abnormalities: low-for-age cellularity (n=4), dysmegakaryopoiesis (n=5), megakaryocytic hypoplasia/
hyperplasia (n=5), and
eosinophilia (n=4). Two patients had multiple immunophenotypic alterations in CD34-positive myeloblasts; 1 patient had clonal hematopoiesis. In contrast, patients who developed
hematologic malignancies had additional
cytopenia(s) (n=4), abnormal platelet granulation (n=5), bone marrow hypercellularity (n=4), dysplasia in ≥2 lineages including megakaryocytes (n=3) and acquired clonal genetic aberrations (n=5). In conclusion, our study demonstrated that specific bone marrow abnormalities and acquired genetic alterations may be harbingers of progression to
hematological malignancies in patients with familial platelet disorder with germline RUNX1 mutation.