Soft tissue sarcoma (STS) is a rare group of malignant tumors originating from mesenchymal cells derived from the mesoderm, arising from various tissues, including bone, cartilage, muscle, fat, blood vessels, and fibrous tissue [[1], [2], [3]]. With over 50 histological subtypes, STS exhibits significant variability in clinical features and treatment responses. While sarcomas constitute less than 1 % of all malignancies, their distribution varies by age: STS is more common in adults, whereas bone sarcomas are predominantly observed in younger individuals [4,5].

Angiosarcoma is a highly aggressive malignancy originating from vascular endothelial cells [[6], [7], [8]]. Although it is exceptionally rare, it constitutes only a small proportion of all sarcomas [9,10]. Angiosarcoma primarily arises in the skin and soft tissues (AS-ST), but it has also been reported in bone (AS-B). Due to its high invasiveness and metastatic potential, angiosarcoma has a poor prognosis, with a reported 5-year survival rate of approximately 30 % [11].

Existing research on angiosarcoma is largely based on small case series or retrospective studies conducted at single institutions. Comprehensive comparisons between AS-ST and AS-B using population-based data remain scarce. Although AS-ST and AS-B share pathological similarities, clinical outcomes may differ due to variations in their primary sites of origin, which remain poorly understood.

Descriptive epidemiological studies utilizing large cancer databases have provided new insights into rare cancers [[12], [13], [14]]. We therefore hypothesized that the use of large cancer databases could clarify the impact of angiosarcoma developing in bone on clinical characteristics. The purpose of this study was to analyze and compare the clinical features and prognostic factors of AS-B and AS-ST using a population-based database.