T-lymphoblastic leukemia/lymphoma

{{Infobox medical condition (new)

| name = T-lymphoblastic leukemia/lymphoma

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| field = Hematology, oncology

| synonyms = Precursor T-cell lymphoblastic lymphoma, Precursor T acute lymphoblastic leukemia/lymphoma

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T-lymphoblastic leukemia/lymphoma (WHO 2008),{{rp|219}} previously labeled precursor T-lymphoblastic leukemia/lymphoma (WHO 2001){{rp|219}} is a form of lymphoid leukemia{{Cite journal|vauthors=Kim MA, Lee GW, Maeng KY |title=An unusual presenting feature of precursor T-cell acute lymphoblastic leukemia/lymphoma |journal=Ann. Hematol. |volume=84 |issue=8 |pages=553–4 |date=August 2005 |pmid=15843931 |doi=10.1007/s00277-005-1042-4|s2cid=40149515 }}{{Cite journal|vauthors=Lyman MD, Neuhauser TS |title=Precursor T-cell acute lymphoblastic leukemia/lymphoma involving the uterine cervix, myometrium, endometrium, and appendix |journal=Ann. Diagn. Pathol. |volume=6 |issue=2 |pages=125–8 |date=April 2002 |pmid=12004362 |doi= 10.1053/adpa.2002.32381}} and lymphoma{{Cite journal |vauthors=Han X, Bueso-Ramos CE |title=Precursor T-cell acute lymphoblastic leukemia/lymphoblastic lymphoma and acute biphenotypic leukemias |journal=American Journal of Clinical Pathology |volume=127 |issue=4 |pages=528–44 |date=April 2007 |pmid=17369128 |doi=10.1309/2QE3A6EKQ8UYDYRC |doi-access=free }}{{Dead link|date=June 2018 |bot=InternetArchiveBot |fix-attempted=no }} in which too many T-cell lymphoblasts (immature white blood cells) are found in the blood, bone marrow, and tissues, particularly mediastinal lymph nodes.{{rp|635}} Labeling as leukemia or lymphoma depends on which feature is more pronounced in a given situation, but has no biological or treatment implication.{{rp|635}}

It is uncommon in adults, but represents 15% of childhood acute lymphoblastic leukemia and 90% of lymphoblastic lymphoma.{{rp|635}}

The 2008 terminology dropped "precursor" to avoid linguistic redundancy because the lymphoblast is an immature precursor cell by definition.{{rp|219}}