Diagnosis of a SMARCA4‐deficient undifferentiated tumor using multigene panel testing: A case report

Key Clinical Message SMARCA4‐deficient thoracic carcinoma is a malignant tumor that may present as cancer of unknown primary. This tumor is refractory and requires a novel approach. In addition to identifying therapeutic targets, multigene panel testing can reveal novel genetic mutations, leading to more pathologically relevant diagnoses and appropriate tumor care. SMARCA4‐deficient undifferentiated tumors are characterized by SMARCA4 inactivation. We present a case of a 74‐year‐old man with an undifferentiated tumor and a novel SMARCA4 mutation detected using multigene panel testing. The tumor was multiagent and refractory to three chemotherapy lines. The test results helped guide appropriate medical management. SMARCA4‐deficient undifferentiated tumors are characterized by SMARCA4 inactivation. We present a case of a 74‐year‐old man with an undifferentiated tumor and a novel SMARCA4 mutation detected using multigene panel testing. The tumor was multiagent and refractory to three chemotherapy lines. The test results helped guide appropriate medical management.