P150

Y. Shinohara*a (Dr), Y. Ishiia (Dr), A. Iwakoshia (Dr), M. Okia (Dr)

a National Hospital Organization Nagoya Medical Center, Nagoya, JAPAN

* shinoyuka0107@gmail.com

Background: Thoracic SMARCA4-deficient undifferentiated tumors (SMARCA4-UT) are a rare and relatively new disease that was first reported in 2015. These tumors frequently occur in the mediastinum and pulmonary hilum, and there is no established treatment. The tumors progresses quickly, and patients often have a poor prognosis.

Case report: Case 1: A 58-year-old man who had dyspnea for two months prior to admission and underwent emergency transport to the previous hospital for exacerbated dyspnea. He was transferred to our hospital for bronchoscopic treatment of a mediastinal tumor that was found to cause an airway stricture by CT scan. On the same day, he underwent airway stenting using a rigid bronchoscope under general anesthesia, and the dyspnea disappeared. On day four, a biopsy was taken from the esophagus, and the patient was diagnosed with a SMARCA4-UT. He received best supportive care because his performance status score was 3; however, he died because due to rapid disease progression on day 22. Case 2: A 64-year-old male who was admitted to his previous hospital for close examination of a mediastinal tumor. He was transferred to our hospital for bronchoscopic treatment, because he had extensive tracheal stenosis, from the trachea to both main bronchi, and dyspnea on exertion. On day two, he underwent airway stenting using a rigid bronchoscope under general anesthesia, and the dyspnea disappeared. He was diagnosed with a SMARCA4-UT by intraoperative biopsy, and radical radiation therapy initiated on day 18. The radiation therapy resulted in tumor shrinkage and an improvement of his performance status score.

Conclusion: We present two cases of patients with SMARCA4-UT with severe airway stenosis that required airway stenting. SMARCA4-UT frequently occur in the mediastinum and pulmonary hilum, and severe airway stenosis can be fatal. However, stenting may enable subsequent treatment.

Disclosure of funding source(s): none