CD7 aberrant expression led to a lineage switch at relapsed childhood acute pre-B lymphoblastic leukemia.

Immunophenotypic changes and lineage switch between diagnosis and relapse in acute lymphoblastic leukemia are uncommon and accompanied by poor outcomes. In this report, a 12-year-old boy with diagnosis of pre-B ALL with an aberrant expression of CD 7 is described. Patient was treated with the ALL-BFM 2000 protocol and suffered an episode of relapse with a lineage switch from pre-B ALL to T cell ALL. This report concludes that presence of aberrant expression of CD7 at diagnosis of pre-B ALL can have prognostic value of lineage switch to T cell ALL at relapse.