title: Intrathyroidal epithelial thymoma/carcinoma showing thymus-like differentiation; comparison with thymic lymphoepithelioma-like carcinoma and a possibility of development from a multipotential stem cell.
abstract: The purpose of our article is to describe the immunohistochemical findings of intrathyroidal epithelial thymoma/carcinoma showing thymus-like differentiation (ITET/CASTLE) of the thyroid in detail, to clarify the difference between ITET/CASTLE and thymic lymphoepithelioma-like carcinoma (LELC), and to discuss the pathogenesis of ITET/CASTLE. We immunohistochemically examined five ITET/CASTLE and eight LELC cases. All of ITET/CASTLE cases were strongly positive for CD5, P63, high-molecular-weight cytokeratin and B-cell CLL/lymphoma-2. Carcinoembryonic antigen-positive carcinoma cells were found in four ITET/CASTLE cases. Neuroendocrine marker-positive carcinoma cells were scattered in all cases. Immunohistochemical findings in thymic LELC were essentially similar to those in ITET/CASTLE, but the sensitivity was different. There is a possibility that ITET/CASTLE and thymic LELC are not the quite same disease entity. We think that ITET/CASTLE is derived from ectopic thymus, but not related to solid cell nests.
authors.affiliation: Department of Diagnostic Pathology, Kuma Hospital, Kobe, Japan. mhirokawa@kuma-h.or.jp
authors.forename: Mitsuyoshi
authors.initials: M
authors.lastname: Hirokawa
authors.forename: Akira
authors.initials: A
authors.lastname: Miyauchi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Minato
authors.forename: Shigeo
authors.initials: S
authors.lastname: Yokoyama
authors.forename: Seiji
authors.initials: S
authors.lastname: Kuma
authors.forename: Masaru
authors.initials: M
authors.lastname: Kojima
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism; D018956:CD5 Antigens / Q000378:metabolism; D002277:Carcinoma / Q000378:metabolism / Q000473:pathology*; D002454:Cell Differentiation; D002467:Cell Nucleus / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D039902:Multipotent Stem Cells / Q000473:pathology*; D012680:Sensitivity and Specificity; D013945:Thymoma / Q000378:metabolism / Q000473:pathology*; D013953:Thymus Neoplasms / Q000378:metabolism / Q000473:pathology*; D013961:Thyroid Gland / Q000378:metabolism / Q000473:pathology; D013964:Thyroid Neoplasms / Q000378:metabolism / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor; D018956:CD5 Antigens