Pediatric T-lymphoblastic leukemia with an entirely mature immunophenotype: a prompt and challenging diagnosis

Children with T-ALL/LBL often requires prompt diagnosis and treatment. Flow cytometric analysis of T-lineage (such as CD3) and immaturity markers (TdT, CD34, CD1a) is usually straightforward for a diagnosis, except in occasional T-ALLs expressing bright CD45 and lack expression of immature markers. Moreover, occasional mature T-cell lymphomas lack surface CD3 expression or aberrantly express immature markers. It’s critical to differentiate T-ALLs from mature T-cell lymphoma in children because of distinct treatments. Here, we summarize the features of pediatric T-ALL cases with an entirely mature immunophenotype.