TdT Negativity and ETP Phenotype in Young Patients with Acute T- Lymphoid Leukemia: A Case Report

TdT is generally positive in patients with T-Acute Lymphoblastic Leukemia/ Lymphoma (T-ALL/LBL) and can often become negative after chemotherapy. TdT negativity at the time of diagnosis is not a common condition and is evaluated in favor of a poor prognosis. Due to its infrequent occurrence, there are not enough clinical studies, and there are often publications on the basis of case and case series. While its incidence increases in young people and children, the possibility of accompanying Early T Precursor (ETP) phenotype also increases. The presence of the ETP phenotype has negative repercussions on prognosis. Here, we will describe the diagnosis and treatment process of a young adult patient with TdT negative T-ALL accompanied by the ETP phenotype.