Thymoma, association with myasthenia gravis and molecular biomarkers: A case report

Thymoma is a malignant epithelial tumor of the thymic gland, most common in anterior mediastinum and includes eight types. Type B2 thymoma is refer to mixed epithelial cell and lymphocyte or cortical. 33 - 40% of patients with thymoma have myasthenia gravis and 15 - 21% myasthenia gravis patients have thymoma. Myasthenia gravis is a T cell-dependent autoantibody-mediated disease. We report a 44-year-old male patient with myasthenia gravis and thymoma type B2 diagnosis in thymus gland and anterior mediastinum with lung metastasis. He got different clinical and molecular diagnostic measures such as histological investigations, IHC, M.D.C.T scan, etc. CD45 (LCA) plays a major role in immune system. Disruption of the equilibrium between protein tyrosine kinase and phosphatase activity (from CD45 and others) can result in immunodeficiency, autoimmunity or malignancy. It also required for thymic selection. Lymphcytes of the patient expressed CD45 around 84% and in tumor it also has been expressed. The relationship between thymoma and thymic carcinoma is poorly understood. EMA is an effective marker to establish the epithelial nature of neoplastic cells. Staining of tumors is clearly related to the degree of tumor differentiation. EMA was reported positive in tumor IHC. Almost all of thymic carcinomas show positive staining for CD5. Although concurrent with the surgery CD5 was negative in Tumor IHC, it was reported 79% in BMA IHC two years later. The results of BMA immunophenotyping showed the expression of CD2(87%), CD3(80%), CD7(71%), CD34(1.5%), CD117 (1.3%), CD19(1.2%), CD10(1.2%), CD20(1%) on Lymphocytes. We suggest some other biomarkers test. LOH in 6q25.2-25.3 is the most common chromosomal deletion and FOXC1 gene is a potential target. HRAS, NRAS, and TP53 mutations have also been reported in some thymomas.

کلیدواژه ها:

thymoma ، biomarker ، cancer