Thymic Epithelial Tumors

Neoplastic epithelial component CK5/6 -P, CK7 +, CK8 -P, CK18 -P, CK19 +, CD57 (leu7) -/+, 

Tumor-assodated lymphocytes predominantly immature T-lymphocytes TdT -P, CDla -P, CD3 -P, CD99 + 

CK19 +/-, CK7 -/+, EMA-P, HER-2 -/+ Tumor-assodated lymphocytes predominantly mature T- and B-lymphocytes (TdT) — 

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Kodama T, Watanabe S, Sato Y, et al. An immunohistochemical study of thymic epithelial tumors. I. Epithelial component. Am J Surg Pathol. 1986 10 26-33. 

Chan JK, Tsang WY, Seneviratne S, Pau MY. The M1C2 antibody 013. Practical application for the study of thymic epithelial tumors. Am J Surg Pathol. 1995 19 1115-1123. 

Hishima T, Fukayama M, Hayashi Y, et al. NE differentiation in thymic epithelial tumors with special reference to thymic carcinoma and atypical thymoma. Hum Pathol. 1998 29 330-338. 

Fukai I, Masaoka A, Hashimoto T, et al. Cytokeratins in normal thymus and thymic epithelial tumors. Cancer. 1993 71 99-105. 

Nakagawa K, Matsuno Y, Kunicoh H, et al. Immunohistochemical KIT (CDl 17) expression in thymic epithelial tumors. Chest. 2005 128 140-144. 

Tateyama H, Eimoto T, Tada T, et al. p53 protein expression and p53 gene mutation in thymic epithelial tumors An immunohistochemical and DNA sequencing study. Am J Clin Pathol. 1995 104 375-381. 

Weirich G, Schneider P, Fellbaum C, et al. p53 alterations in thymic epithelial tumors. Virchows Arch A. 1997 431 17-23. 

Yang Wl, Efird JT, Quintanilla-Martinez L, et al. Cell kinetic study of thymic epithelial tumors using PCNA (PCIO) and Ki-67 (MlB-1) antibodies. Hum Pathol. 1996 27 70-76. 

Tumors that may be confused with CUPS within the mediastinum include thymic neoplasm (thymoma, thymic carcinoid, or thymic carcinoma), thyroid tumors, lymphomas, paragangliomas, and germ cell tumors. Thymomas are generally easy to recognize owing to their characteristic admixture of neoplastic thymic epithelial cells with non-neoplastic lymphocytes. The neoplastic thymic epithelial cells are positive for keratins,... 

Thymomas may occur in the pleura and can be confused with mesothelioma. These neoplasms may be confused with a sarcomatoid mesothelioma with a heavy lymphoid infiltrate or with a lymphohistiocytoid mesothelioma. None of the cases presented by Moran and coworkers showed radiographic evidence of a mediastinal tumor, however 6 cases showed histologic features of a mixed (lymphocyte-epithelial) thymoma. The neoplastic thymic epithelial cells express keratin and CD5. 

Keratin Subclasses As in many other organs, keratin subsets have been analyzed in the normal thymus and in tumors deriving from it. ° In particular, keratins 7, 13, and 18 appear to be expressed in this spectrum of tissues. Keratin 13 is restricted to epithelial cells of the thymic medulla but is shared by thymomas of all types. Keratins 7 and 18 likewise appear to be preferentially seen in neoplastic proliferations of this gland. 

Basaloid squamous cell carcinoma (BSCC) also may be either a primary thymic tumor > ° or a mediastinal metastasis from a primary neoplasm of the oropharynx, hypopharynx, larynx, esophagus, lungs, or anorectal region. Keratin is universally present in BSCC with a diffuse cytoplasmic pattern of labeling, and reactivity for epithelial membrane antigen, keratin 5/6, and p63 may also be observed. h78,80,8i author s experi-... 

CD57 (leu 7) Neuroendocrine tumors T-cell lymphoma and pre T-ALL, chordoma, MPNST, germ cell tumors, papillary thyroid carcinoma, thymic carcinoma, germ cell tumors, synovial sarcoma, carcinoid tumors, schwannoma, mesothelioma, astrocytoma and glioblastoma NK-cells, Schwann cells, gastric chief cells, adrenal medulla, pancreatic islets, renal tubular epithelium, epithelial cells of thymic cortex, retina, oligodendrocytes... 

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