DNA methylation as a new tool for the differential diagnosis between T-LBL and lymphocyte-rich thymoma

T-lymphoblastic lymphoma (T-LBL) and thymoma are two rare primary tumors of the thymus deriving either from T-cell precursors or from thymic epithelial cells, respectively. Some thymoma subtypes (AB, B1, and B2) display numerous reactive terminal deoxynucleotidyl transferase-positive (TdT^(+)) T-cell precursors masking epithelial tumor cells. Therefore, the differential diagnosis between T-LBL and TdT^(+) T-lymphocyte-rich thymoma could be challenging, especially in the case of needle biopsy. …