Patient With Polycythemia Vera With Disease Progression to Blast-Phase Myelofibrosis

Diagnosis and Presentation

R.J. is a 37-year-old male with past medical history significant for hypertension who was referred to a hematologist/oncologist by his PCP due to persistently elevated hematocrit levels. Lab values at the time of evaluation included a WBC 8,000/μL, hematocrit 56%, and platelets of 250,000/µL. His peripheral blood molecular PCR testing for the JAK2 V617F mutation was positive, and his erythropoietin level was on the low end of normal. R.J. was diagnosed with polycythemia vera (PV) and started on aspirin 81 mg/day and phlebotomy to reach a target hematocrit of less than 45%. He felt fairly well and had stable disease for 3 years with intermittent phlebotomy and no thrombotic complications. The need for phlebotomy started to decrease over time, and his WBC had started to trend upward over the past two visits. He also mentioned generalized discomfort in the left side of his abdomen and noted he was not able to eat quite as much in one sitting. 

Interim Monitoring

Due to the change in the lab values, the frequency of CBC evaluations was increased to monthly from every 3 months to be watched more closely. After 2 months, R.J.’s WBC had significantly increased to 40,000/μL. The presence of peripheral blasts was detected at 3% at this time and LDH was elevated. He had not required a phlebotomy in 9 months, and his hematocrit had decreased to 36%. Platelets were slightly lower than baseline at 140,000 /μL. Two weeks later, labs were repeated and significant for leukoerythroblastosis, anemia, and elevated LDH. Spleen was palpable on exam.

Follow-Up Assessment

Bone marrow aspiration and biopsy were performed to confirm progression to myelofibrosis and rule out transformation to acute myeloid leukemia. Results were significant for the presence of reticulin fibrosis and megakaryocyte proliferation and atypia with 7% blasts in the marrow. Molecular panel detected a TET2 mutation in addition to the previously identified JAK2 V617F mutation. Normal karyotype.

Treatment

R.J. was referred for a transplant consultation given the high-risk features of his disease. His age and performance status were favorable for consideration of stem cell transplant. Bridging therapy with a hypomethylating agent and ruxolitinib for two cycles was pursued with the goal of reducing the blasts in the marrow and reducing splenomegaly prior to transplant.

Considerations

Seeing a progressive decrease in hematocrit levels in a patient with PV who once required phlebotomies or cytoreductive therapy should be a red flag. Additionally, increased leukocytosis or the development of peripheral blasts should raise concern for disease transformation. Following the lab trends in patients with PV is incredibly valuable as this is a dynamic disease process with the potential to change overtime.