Polycythemia Vera in a Patient With Heterozygous Beta-Thalassemia: Coincidence or Causal Relationship?

Abstract

Polycythemia vera (PV) and heterozygous beta-thalassemia (HBT) have opposing effects on the hematocrit (Hct) and may mask the presence of each other. Missing the diagnosis of PV may have serious consequences, mainly by exposing the patient to the risk of thromboses. We present a case where the diagnosis of PV was delayed due to the coexistence of HBT, and review the relevant literature. It can be postulated that "stress erythropoiesis", known to occur in patients with thalassemic syndromes, increases the probability of somatic JAK2 mutations leading to development of PV.

Polycythemia vera in patients of beta-thalassemia trait and stress erythropoiesis

“…Beta-thalassemia trait causes mild or asymptomatic anemia rarely requiring any treatment. [ 1 ] In the present case, the patient was a known case of a beta-thalassemia trait and subsequent development of PV (JAK-2 mutation-positive). PV is a myeloproliferative neoplasm caused by a mutation in JAK 2 (95% cases) which leads to a signaling defect and an uncontrolled, neoplastic proliferation of hematopoietic stem cells.…”

“…Beta thalassemia is characterized by a decreased production of the beta subunit of Hb. [ 1 ] Phenotypically it is of three types: thalassemia major, thalassemia intermedia, and thalassemia minor/trait. Beta-thalassemia major has usually been diagnosed in the first two years of life and these patients are transfusion dependent.…”

“…Common in the Mediterranean, the Middle East, and North Africa. [ 1 ] The beta-thalassemia major is characterized by the complete absence of the beta-goblins chain, leading to severe, transfusion-dependent anemia. Thalassemia intermedia includes all the heterogeneous phenotypes of decreased beta-globin production which, occasionally, may lead to transfusion need.…”

The Classification of Myeloproliferative Neoplasms: Rationale, Historical Background and Future Perspectives with Focus on Unclassifiable Cases

“…The global picture strongly favors a diagnosis of MPN, but the differential diagnosis between ET and PV cannot be definitively settled. The former is favored by thrombocytosis and by prominent ET-type megakaryocyte morphology, and the latter is supported by the coexistence of neutrophilia alongside with normal Hb levels (possible effect of the concurrent thalassemic trait) [46]. (d; H/E, 200×), which range in morphology from small/hypolobulated to large/hyperlobulated (e, H/E, 400×); a minor increase in reticulin network, consistent with MF-1 grade is observed (f; Gomori silver stain, 200×).…”

“…The global picture strongly favors a diagnosis of MPN, but the differential diagnosis between ET and PV cannot be definitively settled. The former is favored by thrombocytosis and by prominent ET-type megakaryocyte morphology, and the latter is supported by the coexistence of neutrophilia alongside with normal Hb levels (possible effect of the concurrent thalassemic trait) [46].…”