Background: Acute lymphocytic leukemia, also known as acute lymphoblastic leukemia, is a rapidly progressive proliferation of leukocyte precursors that can be fatal within a few months from onset if left untreated. Acute lymphocytic leukemia is further divided into the sub-types B-cell acute lymphocytic leukemia and T-cell acute lymphoblastic leukemia depending on the lineage of the cancerous cells. Both types can very rarely present in pregnant patients, complicating treatment options due to concern for harm to the fetus or mother.

Case Report: Here we present the case of a 36-year-old primigravida diagnosed with T-cell acute lymphoblastic leukemia at 17 weeks gestation. A routine complete blood count found marked leukocytosis with blasts at white blood cells (WBC) 58 x 103/uL and blasts 66%. Her bone marrow biopsy revealed T lymphoblastic leukemia/lymphoma with leukemic blasts occupying 80% of the marrow space and accounting for 90% of cells. Genetic testing of the white blood cells from her blood sample was negative for BCR-ABL1 fusion (Philadelphia chromosome). She underwent a second-trimester pregnancy termination, was started on a pediatric-inspired acute lymphocytic leukemia treatment regimen and went into remission.

Conclusion: To our knowledge, this case is the first reported case of Philadelphia chromosome-negative T-cell acute lymphoblastic leukemia in a woman of advanced maternal age treated with the older adolescents and young adults regimen for acute lymphocytic leukemia. The availability of first and second-trimester pregnancy termination procedures is a medical necessity in the management of gestational malignant hematologic neoplasia that is illustrated in this case.

Keywords: Pregnancy; Philadelphia chromosome; Precursor cell lymphoblastic leukemia-lymphoma; Precursor t-cell lymphoblastic leukemia-lymphoma; Female