Clinicopathological contributions at diagnosis of bilineal extramedullary blast proliferation

Abstract

Blast phase of chronic myelogenous leukemia (CML) presenting as extramedullary blast proliferation is seen in only 6%–10% of cases. A bilineal blast proliferation of myeloid and T-cell lymphoid lineage is even rarer. These cases usually have various additional cytogenetic clonal abnormalities along with the presence of Philadelphia chromosome (Ph chromosome) or BCR-ABL fusion gene. Considered to be an aggressive hematologic malignancy, it needs prompt initiation of chemotherapy along with Imatinib and stem cell transplant. We report here a case of bilineal extramedullary blast proliferation in a 33-year-old male presenting with an initial diagnosis of CML. Lymphoblastic lymphoma, de novo acute myeloid leukemia are considered as close differentials; absence of proper clinical findings, lack of other components of myeloid differentiation can be potential pitfalls in arriving at a correct diagnosis.