Thymoma Type B3

**Semantic type:** Neoplastic Process

**Definition:** Also known as well-differentiated thymic carcinoma, atypical thymoma, or epithelial thymoma, this type of thymoma displays morphologic characteristics of a well-differentiated carcinoma. The majority of cases occur in the anterior mediastinum as Masaoka stage II or stage III tumors. It is almost always invasive, it recurs frequently, and metastasizes in approximately 20% of the cases.

**Synonyms:** - Atypical Thymoma - Epithelial Malignant Thymoma - Epithelial Thymoma - Malignant Thymoma Type B3 - Squamoid Thymoma - Thymoma, atypical, NOS - Thymoma, atypical, malignant - Thymoma, epithelial, NOS - Thymoma, epithelial, malignant - Thymoma, type B3, NOS - Thymoma, type B3, malignant - Well Differentiated Thymic Carcinoma - Well differentiated thymic carcinoma - Well-Differentiated Thymic Carcinoma