[1256] Development of Monocytosis in Patients with Primary Myelofibrosis Indicates an Accelerated Phase of the Disease.

Rosanny Espinal-Witter, Julia T Geyer, Shalini Verma, Daniel M Knowles, Attilio Orazi. Weill Cornell Medical Center, New York, NY

Background: Primary myelofibrosis (PMF) is a chronic myeloproliferative neoplasm characterized by progressive bone marrow failure with worsening cytopenias. A subset of patients (5-30%) progress to acute leukemia. Better prognostic parameters are needed to identify these patients. We describe a subset of PMF patients who developed monocytosis during the course of disease. Published data have shown that some patients with myelodysplastic syndrome may develop monocytosis resembling chronic myelomonocytic leukemia, and this event usually portends poor prognosis. It is unclear whether such occurrence also has prognostic value in PMF.
Design: Over a three-year period (2008-2010), we identified 8 of 237 cases of PMF in our departmental database, which over time developed persistent absolute monocytosis (≥1x109L). All available bone marrow (BM) samples were reviewed and correlated with monocytosis as well as clinical and laboratory data, JAK2 status, and cytogenetic analysis.
Results: Three patients were women and five were men; mean age: 69.9 years (range 52-82). The mean follow up time after initial diagnosis of PMF was 91.5 months (range 24-204). Monocytosis developed after diagnosis at a mean interval of 51.3 months (range 5–192). Monocyte count ranged from 1.0–26.0x109L. Monocytosis persisted for a mean of 14.7 months (range 0.3-38). Two (25%) patients died after the development of monocytosis, including one patient who developed acute leukemia (7 months) and one patient with circulating blasts (48 months). Five of the six patients who are still alive have worsening/refractory disease. Monocytosis correlated with increased WBC (n=6), decreased hemoglobin (n=4), decreased platelet count (n=3), and circulating blasts (n=4). Review of BM samples showed predominantly granulocytic proliferation in the cellular areas in all cases. Six of eight (75%) patients were JAK2 negative and two (25%) JAK2 positive. Four of eight (50%) patients had normal karyotypes. Cytogenetic abnormalities included del 13q (n=1), trisomy 8 (n=1), trisomy 9 and 21 (n=1), t(1:15) (n=1). There was no cytogenetic evolution or change in JAK2 status associated with the development of monocytosis.
Conclusions: This is the first study correlating monocytosis with clinical follow-up, laboratory data, molecular analysis, and bone marrow morphology in patients with PMF. Our data shows that the development of monocytosis in patients with established PMF is associated with rapid disease progression (i.e. accelerated phase).
Category: Hematopathology

Monday, February 28, 2011 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 169, Monday Morning


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