Patients with SMARCA4-deficient thoracic sarcoma and severe skeletal-related events.

Objectives: SMARCA4-deficient thoracic sarcoma(DTS) is a recently identified new entity of thoracic malignancies characterized by inactivation of SMARCA4. Patients with SMARCA4-DTS have a particulary aggresive clinical course and no effective treatments. However, the detailed clinical features of SMARCA4-DTS remain unclear. Here, we report the clinical courses and molecular profiles of two cases of SMARCA4-DTS.

Materials And Methods: We experienced strikingly similar two patients of SMARCA4-DTS. The clinicopathologic features were reviewed, and detailed immunohistochemical and comprehensive cancer panel analysis with next generation sequencing confirmed the diagnosis.

Results: Our cases had many clinical and radiological observations characteristic of SMARCA4-DTS in common. Immunohistochemical staing showed complete loss of SMARCA4 in tumor cells. Loss of function mutations were detected in SMARCA4. We found that severe SREs comprise a new significant clinical feature of SMARCA4-DTS.

Conclusion: Integrated clinico-radiologic-pathologic-genetic diagnosis is essential for SMARCA4-DTS and physicians should pay attention to severe SREs during the clinical course of this disease.