Indolent T-lymphoblastic proliferation: report of a case with a 16-year course without cytotoxic therapy.
ABSTRACT T-lymphoblastic lymphoma is a high-grade malignant lymphoma. Clinically indolent T-lymphoblastic proliferations have not been described. We present a case report of an indolent T-cell lymphoblastic proliferation studied by histopathology, immunohistochemistry, flow cytometry, antigen receptor gene rearrangement studies, and cytogenetics. The patient had recurrent masses in the upper aerodigestive tract over a 16-year period, was treated by multiple surgical excisions, and never received either chemotherapy or radiotherapy. A proliferation of lymphoblasts was present histologically. The cells were positive for terminal deoxynucleotidyl transferase, CD1, and CD3, and coexpressed CD4 and CD8. No clonal rearrangements of the T-cell receptor beta or gamma chain genes were identified. Cytogenetic studies revealed a questionable inversion of the short arm of chromosome 9, affecting the 9p21-22 region. Although ectopic thymic tissue was considered, the case was considered to be an indolent lymphoblastic proliferation. It should be recognized that rare lymphoblastic proliferations may not behave in a high grade fashion as typically seen in T-lymphoblastic lymphoma.
- SourceAvailable from: PubMed Central01/2015; 49(1):1-4. DOI:10.4132/jptm.2014.11.17
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ABSTRACT: Adenoidal tissue (also known as nasopharyngeal tonsils) of 58% of humans in the pediatric age group contains immature T-lymphoid cells with the phenotype of thymocytes (TdT+,CD1abc+, cytoplasmic CD3+, coexpressing CD4 and CD8, lacking an Intraepithelial Lymphocyte-associated phenotype). The notable difference in comparison to palatine tonsils is the clustering in groups and sheets, comprising hundreds or thousands of cells (1.7%±0.2 of total T cells). The thymic epithelium is morphologically and phenotypically absent. Adenoids share with tonsils and lymph nodes the presence of immature B cell precursors (TdT+, CD1a-, Pax5+, Surrogate light chain±), however in these latter the presence of TdT+, CD1a+, Pax5- precursors is absent or limited to individual cells. Human adenoids are distinct among the Waldeyer's ring lymphoid tissue because of the known embryogenic derivation from the third pharyngeal pouch, from which the thymus develops; in addition, they may display phenotypic incomplete features of a vestigial thymus.PLoS ONE 05/2014; 9(5):e98222. DOI:10.1371/journal.pone.0098222 · 3.53 Impact Factor
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ABSTRACT: To investigate the occurrence of lymphoid progenitor cells in human tonsils, we studied tonsils from children and adults by immunohistochemistry by using a panel of antibodies to antigens associated with lymphoid progenitor cells, including terminal deoxynucleotidyl transferase (TdT), CD10 (CALLA), CD34, CD99 (p30/32mic2), and CD117 (c-kit), and compared them to reactive lymph nodes. Lymphoid progenitor cells, positive for TdT, CD10, and CD99, but not CD34 or CD117, were readily identified in tonsils from children and adults (TdT, 14 of 15; CD10, 15 of 15; CD99, 11 of 15), but were rarely present in lymph nodes (TdT, 1 of 8; CD10, 1 of 8; CD99, 0 of 8). Lymphoid progenitor cells in tonsils were localized to discrete foci at the periphery of lymphoid lobules adjacent to fibrous septae. Lymphoid progenitor cells are present in human tonsils, and the tonsils are a potential site of postnatal lymphopoiesis. The presence of lymphoid progenitor cells in human tonsils should not be confused with lymphoblastic lymphoma or leukemia.International Journal of Surgical Pathology 02/2003; 11(1):21-4. DOI:10.1177/106689690301100105 · 0.96 Impact Factor