SMARCA4 and thymus neoplasm: Interestingly, the malignant cells also showed patchy positivity for PAX-8, and TDT highlighted a few immature T cells, raising the possibility of a thymic neoplasm; however, IHC staining with BRG1 showed malignant cells with loss of SMARCA4/BRG1 expression, rendering the final diagnosis of a SMARCA4-UT (Figures 3, 4).