CD7+ stem cell leukemia/lymphoma. Features of a subgroup without circulating blast cells

Abstract

Recent advances in immunology have clarified the cellular origin of hematopoietic neoplasms. Blast cells with a CD7+ CD4‐ CD8‐ phenotype are demonstrated to originate from malignant pluripotent hematopoietic stem cells. In this article, the authors describe three rare cases, designated as a lymphoma type of CD7+ stem cell leukemia/lymphoma, with clinical features described below. All three patients were admitted with non‐Hodgkin lymphoma with a 2‐month to 4‐month history of lymphadenopathy. Histologic examination of lymph nodes showed lymphoblastic lymphoma (LBL) in all patients. Bone marrow blast cells had an immunophenotype consistent with CD7+ CD4‐ CD8‐ acute leukemia, although abnormal cells were not observed in the peripheral blood during the course of the disease. One patient had a recurrence in the bone marrow, with myeloperoxidase‐positive blast cells expressing myeloid differentiation antigens. Chromosomal analysis detected a common abnormal karyotype initially and at relapse. Furthermore, the same T‐cell receptor gene rearrangement was found initially and at relapse, suggesting that these blast cells originated from the same pluripotent leukemic clone. Additional studies on more patients are required to determine the clinical significance of this group, including the difference from CD7+ stem cell leukemia/lymphoma with circulating blast cells (leukemic type) or LBL. Cancer 1993; 72:99–104.

Electron microscopical analysis of myeloperoxidase of leukemic cells in CD7 + stem cell leukemia/lymphoma

“…These patients do not respond to conventional chemotherapy for either acute lymphoid or myeloid leukemia. Other investigators have reported that leukemic cells of this type of leukemia sometimes expressed myeloid markers (CD13, CD33) during the clinical course of the disease (3)(4)(5)(6). In this study, we report unique ultrastructural morphological and myeloperoxidase features of leukemic cells in a patient with this type of leukemia.…”

Acute undifferentiated leukemia limited to neck lymph nodes and a large mediastinal mass

“…Like AUL, CD7-positive stem cell leukemia is considered to originate from pluripotent hematopoietic stem cells based on the evidence that CD7-positive/CD4/8-negative blast cells have the ability to differentiate into myeloid and lymphoid lineages. 15,16 In the presented case, we presumed that the blast cells originated from pluripotent hematopoietic stem cells prior to the prothymocyte stage because of the lack of CD3 which is usually observed in the process of differentiation into prothymocytes. 14 Chromosomal analysis from the patient's G-banding patterns revealed the presence of tetraploidy (92, XXYY).…”

“…Before the revision of the classification, some cases of leukemia, which were only positive for CD7 and had no lineage markers like this case were reported; they were called CD7positive stem cell leukemia. [14][15][16] CD7-positive stem cell leukemias frequently exhibit bone marrow invasion, mediastinal masses, and lymphadenopathy. These leukemias are characterized by rearrangements of the TCR or immunoglobulin heavy chain and show at relapse myeloid or lymphoid lineages.…”

Aleukemic extramedullary T lymphoid/myeloid bilineage hematopoietic and lymphoid malignancy with progression to bilineage leukemia at relapse: A case report

“…This indicated that the neoplastic cells of T-SCL/lymphoma originated from the HSCs, which maintained the ability to differentiate into lymphoid and myeloid lineages ( 26 , 30 ). In almost all the reported T-SCL/lymphoma cases, the patients presented with a giant mass in the mediastinum or lymph nodes, with coexpression of T lymphoid and myeloid phenotypes on blast cells ( 27 , 29 ). However, with molecular and immunological progress in the studies of hematopoietic diseases, the diagnostic criteria depending only on the expression of CD7, CD4 and CD8 were far from accurate.…”