title: Exuberant cortical thymocyte proliferation mimicking T-lymphoblastic lymphoma within recurrent large inguinal lymph node masses of localized Castleman disease.
abstract: We report a 13-year-old adolescent girl, the youngest thus far, with "an indolent T-lymphoblastic" proliferation (~10%) that uniquely presented within recurrent, large inguinal lymph node masses in a predominating (90%) background of Castleman disease. These nodal masses were resected thrice; the patient is well 5 years after diagnosis without further treatment. Histologically, the features of Castleman disease, hyaline vascular type, were present. Importantly, the interfollicular T-lymphoblastic component occurred as multiple clusters and islands of variable shapes and sizes composed of small "lymphoblasts" indistinguishable from normal cortical thymocytes but without thymic epithelial cells. Immunohistochemically, these lymphoblasts were consistent with the intermediate stage of T-cell differentiation (TdT(+)CD34(-)CD99(+)CD1a(+)CD2(+)CD3(+)CD4(+)CD8(+)CD5(+)CD7(+)CD10(+) [subset]), with 80% Ki-67. Molecularly, the T cells were nonclonal. Our case provides evidence for the benign nature of this highly unusual and poorly understood entity; because the current terminology can be readily misinterpreted as an indolent lymphoblastic lymphoma, we suggest a new term accurately reflecting this entity.
authors.affiliation: Formerly, Department of Pathology, Cedars-Sinai Medical Center, Los Angeles, CA 90048; Department of Pathology, University of California at Los Angeles, Los Angeles, CA 90095.
authors.forename: Rina
authors.initials: R
authors.lastname: Kansal
authors.affiliation: Formerly, Department of Pathology, Cedars-Sinai Medical Center, Los Angeles, CA 90048; Department of Pathology, City of Hope National Medical Center, Los Angeles, CA 91010.
authors.forename: Bharat N
authors.initials: BN
authors.lastname: Nathwani
authors.affiliation: Department of Hematology, Athens Medical Center-Psychikon Branch, 11525 Athens, Greece.
authors.forename: Xanthi
authors.initials: X
authors.lastname: Yiakoumis
authors.affiliation: Department of Hematology, Athens Medical Center-Psychikon Branch, 11525 Athens, Greece.
authors.forename: Maria
authors.initials: M
authors.lastname: Moschogiannis
authors.affiliation: Department of Hematology, Athens Medical Center-Psychikon Branch, 11525 Athens, Greece.
authors.forename: Sotirios
authors.initials: S
authors.lastname: Sachanas
authors.affiliation: Department of Pathology, "Ag Sofia" Children's Hospital, 11527 Athens, Greece.
authors.forename: Kalliopi
authors.initials: K
authors.lastname: Stefanaki
authors.affiliation: Department of Hematology, Athens Medical Center-Psychikon Branch, 11525 Athens, Greece. Electronic address: pangalis@med.uoa.gr.
authors.forename: Gerassimos A
authors.initials: GA
authors.lastname: Pangalis
mesh_terms: D000293:Adolescent; D015415:Biomarkers / Q000032:analysis; D001706:Biopsy; D005871:Castleman Disease / Q000276:immunology / Q000473:pathology* / Q000601:surgery; D049109:Cell Proliferation; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008198:Lymph Nodes / Q000276:immunology / Q000473:pathology* / Q000601:surgery; D054218:Precursor T-Cell Lymphoblastic Leukemia-Lymphoma / Q000276:immunology / Q000473:pathology*; D011237:Predictive Value of Tests; D012008:Recurrence; D060168:Thymocytes / Q000276:immunology / Q000473:pathology*; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers
keywords: Castleman disease; Cortical thymocytes; Extrathymic T cells; Indolent lymphoblastic proliferation; Lymph node; Lymphoblastic lymphoma; TdT