Thoracic SMARCA4-deficient undifferentiated tumour – a case of an aggressive neoplasm

SMARCA4-deficient undifferentiated tumours exhibit undifferentiated and rhabdoid features. These highly aggressive neoplasms pose significant diagnostic challenges. They are characterised by an inactivating mutation of SMARCA4, leading to the loss of expression of Brahma-related gene 1 ( BRG1 ). Despite their rareness and poor differentiation as thoracic tumours, it is important to recognise these tumours because, despite being highly aggressive, there are potential treatment options for the future, such as immunotherapy and SMARCA4-targeted therapies. This case presentation aims to raise awareness of this rare neoplasm when evaluating cases presenting undifferentiated morphology.