Introduction: Angiosarcoma is a rare endothelial malignant neoplasm with variable clinical behavior, predominantly aggressive, originating in endothelial cells. Its presentation in the chest wall is unusual and its diagnosis is often complex, and it can evolve into serious complications such as metastatic splenic rupture.

Clinical case: We present the case of a 47-year-old male patient who presented with a tumor in the left anterior rib cage. The first biopsy was inconclusive. The clinical evolution was accelerated, presenting from persistent bleeding from the surgical wound and subsequent massive hemoperitoneum secondary to a grade V splenic lesion due to splenic metastasis, where multiple metastatic lesions were also evident in the liver, intestine and peritoneum. An extension study such as computed tomography of the skull, thorax, abdomen and pelvis was performed, where metastatic lesions were evident, as well as in the skin, brain and lung. Patient who also presented severe systemic deterioration. Histopathological examination of the splenic specimen revealed vascular neoplasia compatible with low-grade angiosarcoma.

Discussion: This case underscores the rarity of the initial presentation, the biological aggressiveness of angiosarcoma even in low-grade forms, its capacity for hematogenous dissemination with an extensive metastatic pattern, and the inherent difficulties in managing surgical complications in cancer patients. Metastatic splenic rupture, although uncommon, represents a true surgical emergency requiring an immediate and aggressive multidisciplinary approach, even when the overall prognosis is guarded.

Conclusion: Splenic rupture due to metastatic angiosarcoma represents a serious complication in the course of advanced disease. This case highlights the importance of maintaining a high clinical suspicion in the presence of rapidly growing thoracic masses and reaffirms the value of damage control surgery as a palliative strategy in selected acute settings.