Diagnosis and management of gastrointestinal SMARCA4-deficient undifferentiated tumors

First-line combination therapy of immunotherapy plus anti-angiogenic drug for thoracic SMARCA4-deficient undifferentiated tumors in AIDS: a case report and review of the literature

Background

Thoracic SMARCA4-deficient undifferentiated tumors (SMARCA4-UT) exhibit a notably aggressive phenotype, which is associated with poor patient survival outcomes. These tumors are generally resistant to conventional cytotoxic chemotherapy, thereby limiting the availability of effective treatment options.

Case presentation

We describe a 69-year-old AIDS patient who initially presented with a fused, enlarged lymph node on the right clavicle and mild, unexplained pain under the right axilla that worsened with severe coughing episodes. An initial chest CT scan revealed multiple nodular and mass shadows in the mediastinum and multiple nodules in both lungs, as well as a small amount of pericardial effusion. Additionally, serum biomarkers of lung cancer were abnormal as follows: carcinoembryonic antigen (CEA) at 13.74 ng/mL, cytokeratin 19 fragment (CYFRA21-1) at 6.82 ng/mL, neuron-specific enolase (NSE) at 25.49 ng/mL, and progastrin-releasing peptide precursor (ProGRP) at 89.35 pg/mL. Subsequent pathology confirmed SMARCA4-deficient undifferentiated tumors. Considering that the weak immune status and intermediate PD-L1 level, the patient was treated with a first-line combination therapy of immunotherapy and anti-angiogenic drug instead of chemo-immunotherapy. The patient responded well to immunotherapy combining anti-angiogenic drugs and achieved an overall survival for more than 22 months.

Conclusion

Our study presented a rare case of thoracic SMARCA4-deficient undifferentiated tumors and AIDS, suggesting that first-line immunotherapy plus anti-angiogenic drugs as a potential therapeutic option for SMARCA4-UT patients under specific conditions.

A Case of Thoracic SMARCA4-Deficient Undifferentiated Tumor on 18F-FDG PET/CT

A 65-year-old man, who denied a smoking history, presented with chest distress and pain persisting for over a week. A contrast-enhanced chest CT scan revealed a large irregular mass in the right thoracic cavity with heterogeneous enhancement. The 18F-FDG PET/CT showed a large mass in the right thoracic cavity with heterogeneous markedly high FDG uptake. The patient subsequently underwent a bronchoscopic-guided mucosal biopsy at the opening of the right upper lobe. The histological and immunohistochemical findings were consistent with thoracic SMARCA4-deficient undifferentiated tumor.

Thoracic SMARCA4-deficient undifferentiated tumor: current knowledge and future perspectives

Thoracic SMARCA4-deficient undifferentiated tumor is a newly recognized disease entity characterized as a high-grade malignant neoplasm with an undifferentiated or rhabdoid phenotype. The tumor was initially identified as a subtype of thoracic sarcoma with SMARCA4 loss, but further investigation resulted in its classification as a subtype of epithelial malignancies in the current World Health Organization classification. SMARCA4-deficient undifferentiated tumor is highly aggressive and has a poor prognosis. Because of its rarity, an optimal treatment strategy has not yet been identified. In this review, we summarize the literature on SMARCA4-deficient undifferentiated tumor in terms of its clinical characteristics, diagnosis, treatment strategy and future perspectives.