Pretreatment biopsy for thymic epithelial tumors—does histology subtype matter for treatment strategy?

Thymic epithelial tumors (TETs) originate from thymic epithelial cells and represent a heterogeneous group of malignancies including thymomas and thymic carcinomas. Thymomas are relatively rare tumors, with an estimated incidence of 0.13 per 100,000 person-years in the United States (US) (1). Thymomas are the most frequently encountered masses in the anterior mediastinum. However, differentiating thymomas from more malignant considerations such as thymic carcinomas, lymphomas, neuroendocrine tumors, malignant germ cell tumors and metastasis is important as the treatment approach can differ drastically (2). However, it is unclear if further defining the World Health Organization (WHO) histologic subtype of TET adds to the importance of clinical staging in deciding the treatment approach.