title: Thymic epithelial cells expressed unusual follicular dendritic cell markers: thymic extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue.
abstract: Described herein is a case of thymic extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue. Using immunohistochemical double staining it was found that most of the thymic lymphoid follicles in this case possessed cytokeratin-positive and follicular dendritic cell (FDC) marker-positive cells. Moreover, using immunoelectron microscopy it was confirmed that some of the double-positive cells were thymic epithelial cells. The candidate of cytokeratin subtype expressed on the double-positive cells was cytokeratin 1 (CK1), which was expressed only by the epithelium of Hassall's corpuscles in thymuses from age-matched patients with myasthenia gravis. The present case indicates a possibility that some thymic epithelial cells become FDC, although it was uncertain whether they were derived from the epithelia of Hassall's corpuscles or whether they were at the same differentiation stage as Hassall's corpuscles.
authors.affiliation: Department of Surgical Pathology, Showa University Fujigaoka Hospital, Yokohama, Japan. acchi@yk9.so-net.ne.jp
authors.forename: Atsuko
authors.initials: A
authors.lastname: Masunaga
authors.forename: Sanju
authors.initials: S
authors.lastname: Iwamoto
authors.forename: Hisayoshi
authors.initials: H
authors.lastname: Nakamura
authors.forename: Rhosuke
authors.initials: R
authors.lastname: Usuda
authors.forename: Mikio
authors.initials: M
authors.lastname: Masuda
authors.forename: Shuichi
authors.initials: S
authors.lastname: Suzuki
authors.forename: Akira
authors.initials: A
authors.lastname: Miyazaki
authors.forename: Takashi
authors.initials: T
authors.lastname: Suzuki
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Mitsuya
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Yoshitake
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism; D020566:Dendritic Cells, Follicular / Q000378:metabolism* / Q000473:pathology; D004847:Epithelial Cells / Q000378:metabolism / Q000648:ultrastructure; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D018442:Lymphoma, B-Cell, Marginal Zone / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D016253:Microscopy, Immunoelectron; D017464:Receptors, Complement 3d / Q000032:analysis; D013934:Thymectomy; D013950:Thymus Gland / Q000378:metabolism* / Q000473:pathology; D013953:Thymus Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000601:surgery
chemical_list: D014408:Biomarkers, Tumor; D017464:Receptors, Complement 3d