Thymic epithelial cells expressed unusual follicular dendritic cell markers: thymic extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue.
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.
Masunaga
Atsuko
A
Department of Surgical Pathology, Showa University Fujigaoka Hospital, Yokohama, Japan. acchi@yk9.so-net.ne.jp
Iwamoto
Sanju
S
Nakamura
Hisayoshi
H
Usuda
Rhosuke
R
Masuda
Mikio
M
Suzuki
Shuichi
S
Miyazaki
Akira
A
Suzuki
Takashi
T
Mitsuya
Toshiyuki
T
Yoshitake
Tsuyoshi
T
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
D014408:Biomarkers, Tumor; D017464:Receptors, Complement 3d