Acute myelomonocytic leukemia and T-lymphoblastic lymphoma as simultaneous bilineage hematologic malignancy treated with decitabine: A case report

BACKGROUND: Simultaneous bilineage hematologic malignancies are rare; however, several cases of acute myeloid leukemia (AML) and T-lymphoblastic lymphoma (T-LBL) co-occurrence have been reported. A standard treatment for simultaneous AML and T-LBL has not yet been established, and its prognosis is very poor. Further studies to develop standard treatments are required to increase patient survival rates. CASE SUMMARY: A 69-year-old man complaining of pleuritic chest pain visited the emergency room. Computed tomography revealed multiple enlarged lymph nodes (LNs) in the neck and groin and pulmonary thromboembolism with pulmonary infarction. Furthermore, a peripheral blood smear performed due to leukocytosis revealed circulating blasts. Acute myelomonocytic leukemia (AMML) was diagnosed after bone marrow examination, and T-LBL positivity for terminal deoxynucleotidyl transferase, cluster of differentiation (CD)34, and CD4 was confirmed by cervical LN biopsy. Decitabine and dexamethasone were administered because he could not receive intensive chemotherapy due to poor performance status. Complete remission of AMML and T-LBL was achieved after 4 cycles of decitabine plus dexamethasone. CONCLUSION: We report the therapeutic effect of decitabine, a hypomethylating agent (HMA), in patients with concurrent bilineage hematologic malignancies and suggest that further studies are required to evaluate the therapeutic effect of HMAs on both lymphoid and bilineage hematologic malignancies.