F 49, anterial mediastinal mass with myasthenia gravis
Normal Thymus Fibrous septa Tumor border
Type B2 Thymoma Epithelial tumor cells and background immature T lymphocytes
Type B2 Thymoma Epithelial tumor cells (arrows)
large, polygonal tumour cells that are arranged in a loose network
Type B2 Thymoma Definition: Type B2 thymoma is an organotypical thymic epithelial neoplasm composed of large, polygonal tumour cells that are arranged in a loose network and exhibit large vesicular nuclei, closely resembling the predominant epithelial cells of the normal thymic cortex. A background population of immature T cells is always present and usually outnumbers the neoplastic epithelial cells Synonyms: Cortical thymoma Lymphocytic thymoma (obsolete) Mixed lymphocytic and epithelial thymoma (obsolete)