Diagnostic Challenges of Early T-cell Precursor Acute Lymphoblastic Leukemia: A Case Report and Literature Review

Early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) is an uncommon subtype of T-cell acute lymphoblastic leukemia (T-ALL), constituting approximately 10-13% of T-ALL cases in childhood and 5-10% in adults. A 55-year-old female patient presented with no significant medical history and was hospitalized in the internal medicine department due to anemia and deterioration of her overall health. The clinical examination did not reveal any tumor syndrome. A complete blood count was performed showing normocytic normochromic anemia with leukocytosis. The myelogram revealed bone marrow invasion by blasts of 80%. Immunophenotyping revealed the presence of a blast population of T lymphoid nature estimated at 74% of the marrow elements with a particular immunophenotype. Thus, the diagnosis of ETP-ALL was retained. A karyotype was carried out showing the presence of a hypotetraploid clone with clonal anomalies in number and structure. The patient was put on hyper-CVAD protocol (cyclophosphamide, doxorubicine, vincristine, dexamethasone). A myelogram at the end of induction revealed the presence of 45% blasts. The categorization of ETP-ALL as a distinct entity in the WHO classification arises from its distinguishable phenotypic and genetic characteristics. However, the diagnosis and management of ETP-ALL always constitutes a challenge for the biologist and clinician. Therefore, it is essential to conduct more extensive studies for a better comprehension of the clinical and biological features of ETP-ALL, specifically focusing on its genetic nuances.