“A Fatal Transformation”: A Case Report on Essential Thrombocythemia Transformed to Acute Myelogenous Leukemia

Abstract

Essential thrombocythemia is a benign myelodysplastic disorder. However, it can transform into a more malignant disorder such as acute myelogenous leukemia (AML). Here, we report a case of a 60-year-old lady diagnosed with essential thrombocythemia (JAK2 and BCR-ABL negative) and was treated with hydroxyurea. She also has comorbid disease of diabetes type II and bronchial asthma. She developed persistent pancytopenia and hydroxyurea was withheld since then. Repeated full blood picture analysis shows white cell of 6.3 x 10⁹/L with 28% of leukemic blast cells. The blast showed negative staining with myeloperoxidase by immunostaining. Immunophenotyping of bone marrow aspirate shows presence of a blast population gated at CD45 and the cells are positive for immature markers of CD34, HLA DR, CD117, myeloid associated marker CD13 (bright), CD33 (heterogeneous), CD38 and CD71.  Bone marrow BCR ABL analysis was undetectable. Based on these findings, the leukemic blast cells were classified as AML. Patient was given induction chemotherapy with daunorubicin (60 mg/m² per day for three days) and cytarabine (100 mg/m² per day for seven days). In conclusion, leukemic transformation can occur in essential thrombocytosis, and any eligible patients should be given chemotherapy as per protocol for AML.