Thoracic SMARCA4-deficient undifferentiated tumor (SMARCA4-UT) is a high-grade malignant neoplasm characterized in the 5th edition of the World Health Organization classification of thoracic tumors by an undifferentiated or rhabdoid morphology and characteristic loss of SMARCA4 expression in tumor cells [1,2]. Here, SMARCA4 is linked to neoplasm.