Decitabine-containing G-CSF priming regimen overcomes resistance of primary mediastinal neoplasm from early T-cell precursors to conventional chemotherapy: a case report

Yuhuan Yang,1,* Shuna Yao,1,* Jiuyang Zhang,1 Zheng Yan,1 Junfeng Chu,1 Haiying Wang,1 Zhihua Yao,1 Fan Zhang,2 Qingxin Xia,3 Yanyan Liu11Department of Internal Medicine, Affiliated Cancer Hospital of Zhengzhou University, Zhengzhou, Henan, People’s Republic of China; 2Department of Central Laboratory, Affiliated Cancer Hospital of Zhengzhou University, Zhengzhou, Henan, People’s Republic of China; 3Department of Pathology, Affiliated Cancer Hospital of Zhengzhou University, Zhengzhou, Henan, People’s Republic of ChinaCorrespondence: Yanyan LiuDepartment of Internal Medicine, Affiliated Cancer Hospital of Zhengzhou University, 127 Dong Ming Road, Zhengzhou, Henan 450008, People’s Republic of ChinaEmail yyliu@zzu.edu.cnQingxin XiaDepartment of Pathology, Affiliated Cancer Hospital of Zhengzhou University, 127 Dong Ming Road, Zhengzhou, Henan 450008, People’s Republic of ChinaEmail 13838173710@139.com*These authors contributed equally to this workAbstract: Early T-cell precursor (ETP) leukemia represents a new subtype of T-lymphoblastic leukemia/lymphoma with unique immunophenotypes expressing T-cell and one or more of the myeloid/stem cell markers. Here, we report a young patient who had primary mediastinal mass and pleural effusion without bone marrow involvement. A CT-guided mediastinal biopsy and flow cytometry analysis of the pleural effusion revealed the blast cells to have complicated immunophenotypes: strongly expressed T-cell antigen CD7, myeloid-lineage antigens CD33 and CD13 and stem cell markers cTdT, CD34, and HLA-DR; dimly expressed myeloid-lineage specific antigen cMPO and B-cell antigen cCD79a; but did not express T-cell specific antigen cytoplasmic CD3 and B-cell specific antigen CD19. Clonal T-cell receptor rearrangement eventually determined the cell of origin from ETPs, not myeloblasts. The patient showed primary resistance to lymphoid and myeloid-directed induction therapy. Finally, low-dose decitabine combined with modified-CAG regimen induced a complete remission and allogeneic stem cell transplantation was performed as consolidation. The case indicates a primary mediastinal neoplasm from ETP with distinctive immunophenotype from leukemia type. Low-dose decitabine and modified-CAG regimen in combination with allogeneic stem cell transplantation may improve the outcome of patient.Keywords: early T-cell precursor, decitabine, G-CSF priming, T-lymphoblastic lymphoma