Case report and literature review on T-SMARCA4-DUT diagnosis and treatment response in a single patient

This source is a case report and literature review focusing on thoracic SMARCA4-deficient undifferentiated tumor (T-SMARCA4-DUT), lung adenocarcinoma, and mediastinal lymphoma. The narrative centers on a single 64-year-old male patient whose initial diagnosis was suspected mediastinal lymphoma based on CECCT imaging but was pathologically confirmed as metastatic poorly differentiated lung adenocarcinoma. The authors review the clinical course of this specific case to highlight diagnostic challenges associated with this rare tumor type.

The patient received combined chemotherapy plus immunotherapy, which resulted in tumor shrinkage. However, subsequent development of bilateral axillary lymphadenopathy occurred, leading to a revised diagnosis of lymph node-metastatic T-SMARCA4-DUT. The review notes that the non-specific clinical features of T-SMARCA4-DUT and an inadequate initial immunohistochemistry panel contributed to the initial diagnostic confusion. No specific adverse events or tolerability data were reported for this single case.

The authors conclude that definitive diagnosis requires testing for SMARCA4/Brg1, SOX2, and the highly specific TTF-1 (clone 8G7G3/1). Given the limitations of non-specific clinical features and the potential for initial misdiagnosis, clinicians should maintain a high index of suspicion for T-SMARCA4-DUT in appropriate contexts. The practice relevance underscores the necessity of comprehensive molecular profiling to avoid diagnostic errors in complex thoracic malignancies.