title: Well-differentiated thymic carcinoma. An organotypical low-grade carcinoma with relationship to cortical thymoma.
abstract: Based on a study of 26 cases, the well-differentiated thymic carcinoma is described as a distinct organotypical carcinoma of the thymus with low-grade malignancy. It is characterized by a predominance of epithelial cells with usually low mitotic rate, an epidermoid differentiation with slight to moderate cytological atypia, the constant presence of interepithelial immature cortical thymocytes, lobular growth, and formation of epithelial palisades around perivascular spaces. The tumor occurs at age 14 to 76 years in both sexes. An association with myasthenia gravis is found in 77% of the patients, and 83% of the tumors show invasion of adjacent organs or endothoracic metastasis at primary operation. This rate is higher than in cortical thymomas (47%) but lower than in other thymic carcinomas (92%). Two of 18 patients with follow-up died of tumor recurrence and pleural metastasis. Well-differentiated thymic carcinoma can be related to cortical thymoma by common morphological features and a similar immunophenotype of epithelial cells. It must be differentiated from the lymphocyte-depleted cortical thymomas after corticosteroid treatment and from the benign epithelial-rich medullary thymomas.
authors.affiliation: Institute of Pathology, University of Wüzburg, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Kirchner
authors.forename: B
authors.initials: B
authors.lastname: Schalke
authors.forename: J
authors.initials: J
authors.lastname: Buchwald
authors.forename: M
authors.initials: M
authors.lastname: Ritter
authors.forename: A
authors.initials: A
authors.lastname: Marx
authors.forename: H K
authors.initials: HK
authors.lastname: Müller-Hermelink
mesh_terms: D000293:Adolescent; D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000188:drug therapy / Q000473:pathology* / Q000601:surgery; D002294:Carcinoma, Squamous Cell / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D005629:Frozen Sections; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000209:etiology; D013945:Thymoma / Q000188:drug therapy / Q000473:pathology* / Q000601:surgery; D013950:Thymus Gland / Q000473:pathology; D013953:Thymus Neoplasms / Q000188:drug therapy / Q000473:pathology* / Q000601:surgery; D013997:Time Factors
chemical_list: D000305:Adrenal Cortex Hormones