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Researchers Further Characterize MPN First Identified in 1991, Offer Genetic Clues
Researchers have identified 15 patients with a distinct myeloproliferative neoplasm (MPN), which they propose naming “clonal megakaryocyte dysplasia.” This new disorder, according to the researchers, is distinct from prefibrotic myelofibrosis (pre-PMF).
“In 1991, we reported 18 persons with a clinical-pathologic entity, and termed atypical myeloproliferative disorder because they did not meet the contemporary diagnostic criteria for a MPN,” wrote Giovanni Barosi, Center for the Study of Myelofibrosis, Laboratory of Biochemistry, Biotechnology and Advanced Diagnostics, Istituto di Ricovero e Cura a Carattere Scientifico Policlinico S. Matteo Foundation, Pavia, Italy, and co-authors.
The researchers conducted a retrospective cohort study of patients registered in the database of the Center for the Study of Myelofibrosis in Pavia, Italy, from 1998 to June 2020. The scientists studied clinical, histological, cytogenetic, and molecular covariates and risks of thrombosis, disease progression, and death, and compared the data with those of 546 patients with pre-PMF. A mutation in the gene JAK2V617F was present in 10 patients and CALR mutation in 1.
Fifteen new subjects with atypical myeloproliferative disorder were identified (7 male). The median age was 50 years (IQR, 41–54 years). Thirteen were diagnosed with a synchronous symptomatic or incidentally detected thrombotic event. The bone marrow showed megakaryocyte hyperplasia with dysplasia.
After a median follow-up of 101 months (IQR, 40–160 months), no patients had disease progression or blast transformation. Incidence of post-diagnosis or recurrent thrombosis was 3.9 events (95% confidence interval, 3.5–4.0) and 5.0 events (4.6–5.6) per 100 person-years.
Researchers concluded that features of patients with atypical myeloproliferative disorder differed markedly from those of patients with pre-PMF.
