[CD5+, CD7+, and CD19+ non-Hodgkin's lymphoma in a child]

The 9-year-old boy was admitted to Shizuoka Children's Hospital because of cervical lymphoadenopathy. Complete blood count showed normal RBC and platelet counts. WBC was 2700/microliters with no tumor cells. Bone marrow aspirate showed normocellularity with 34% tumor cells. Lymph node biopsy from his right neck was performed and the patient was diagnosed as non-Hodgkin's lymphoma (lymphoblastic type). Surface marker analysis disclosed that the tumor cells were positive for CD5, CD7, CD19, CD38, CD71, and Ia antigen. Chromosomal analysis of the cervical lymph node revealed 46, XY, t(7;14) (p15;q32). Molecular investigation with appropriate probe showed germ-line configurations of IgH gene, TcR beta gene, and TcR gamma gene, and one rearranged band of TcR delta gene. Monoclonality of tumor cells was demonstrated from chromosomal analysis and molecular study. CD7 and CD19 are not lineage specific antigens because CD7 is expressed on immature AML cells and CD19 is expressed on T ALL cells or AML cells. Moreover, TcR delta rearrangement is considered to occur at early phase of hematolymphoid cells. Based on these data, tumor cells of this patient is considered to originate from immature lymphoid cell, so-called lymphoid stem cell.