Molecular analysis of T-cell Acute Lymphoblastic Leukemia arising after Essential Thrombocythemia foreshadows a distinct clonal route for lymphoid blast crisis in Philadelphia-negative chronic myeloproliferative neoplasm: a case report with literary review.

Progression to Acute Myeloid Leukemia is a well-known complication of classical philadelphia-negative chronic myeloproliferative neoplasms, while disease progression to Acute Lymphoblastic Leukemia remains an extremely unfrequent event. A molecular explanation for this rare phenomenon is missing. However, the clonal haematopoiesis mostly present in these patients may work as a seeding soil for a second neoplastic disease. Molecular results from this case study reporting a secondary Acute Lymphoblastic Leukemia presenting after Essential Thrombocythemia support this hypothesis. In this contest secondary Acute Lymphoblastic Leukemia should not be considered as real blast crisis, but rather as a second cancer determined by a different clonal route. Given the unique features of this case, a review of the published cases of MPN transforming to Acute Lymphoblastic Leukemia available in literature is provided in the article.