Case Study Highlights Polycythemia Vera, Pure Erythroid Leukemia Connection

Adding to the limited evidence available on pure erythroid leukemia (PEL), a rare and aggressive form of acute leukemia, researchers have published their findings of a patient with the disease following transformation from polycythemia vera (PV).

Their study appeared recently in Cureus.

PEL, defined by immature erythroid precursors levels above 80%—of which 30% are proerythroblasts—accounts for less than 1% of all acute myeloid leukemia cases, the authors noted, and carries a poor prognosis, with a median overall survival of 2 to 3 months.

Just a handful of cases have been reported of PEL arising from myeloproliferative neoplasms (MPNs), such as PV. According to the researchers of the current case study, just 5 such cases were reported between 1952 and 1962.

In this most recent documented case, a 67-year-old female was living with PV for 7 years before the chronic MPN evolved into PEL, which was discovered following complaints of ongoing fatigue, darker urine, and swollen legs. Testing revealed leukocytosis, anemia, and thrombocytopenia, and subsequent bone marrow aspirate findings were consistent with PEL.

“The mechanism underlying leukemic progression remains unclear and has been suggested to be multifactorial. Advanced age and leukocytosis are well-established risk factors in patients with PV for progression to myelofibrosis,” explained the researchers.

“Other factors associated with leukemic transformation include previous exposure to myelosuppressive therapy, abnormal karyotypes, and certain mutations in genes such as serine/arginine-rich splicing factor 2 and isocitrate dehydrogenase 1/2,” they added.

Adding to an already rare phenomenon, the researchers noted that unlike most of the previously reported cases, which were associated with radiation therapy or chemotherapy with alkylating agents. In contrast, the patient of the current case report received treatment for her PV via phlebotomy and hydroxyurea prior to her disease evolving into PEL.

This finding may have important implications, as hydroxyurea as firstline treatment for PV has increased in recent decades.

“There remains some confusion in pinpointing the pathogenesis of PEL in our patient. Some studies have accepted leukemic transformation as a late event in the natural progression of PV,” explained the researchers. “Our patient’s duration of disease and long-term use of hydroxyurea does not allow for easy discrimination between the risk of hematologic transformation due to the natural evolution of the disease and that due to long-term pharmacologic cytoreduction. We speculate whether hydroxyurea may have a leukemogenic risk in PV.”

Reference

Liu L, Dudheker N, Sumarriva Lezama LM, Shah S, Nwaokoro M, Ranpura V. Transformation of polycythemia vera to pure erythroid leukemia. Cureus. Published online July 4, 2021. doi:10.7759/cureus.16168