Abstract
A 63-year-old woman presented with worsening dyspnea. Imaging revealed a right atrial mass extending to the left atrium, pulmonary veins, and vena cavae. Biopsy showed spindle-shaped cells with pleomorphism and high mitotic activity. Immunohistochemistry showed positive staining for SMA, desmin, and MDM2, supporting a diagnosis of intimal sarcoma. Due to the tumor's inoperability, she was offered palliative care. The tumour rapidly progressed, leading to pulmonary vein stenosis and obstruction of the vena cavae, leading to obstructive shock. This case illustrates the aggressive nature of intimal sarcomas, which present with local infiltration and obstructive symptoms.