Primary intraosseous alveolar soft part sarcoma: Report of two cases with radiologic-pathologic correlation

Alveolar soft part sarcoma (ASPS) accounts for less than 1 % of all soft tissue sarcomas. ASPS presents a poor prognosis and develops frequent metastases, especially in the lungs, brain and bones. Current therapies, such as surgery, radiotherapy and chemotherapy, are not fully effective and other alternative treatments are currently being studied. ASPS is predominantly found in the deep soft tissues of the lower extremities. To our knowledge, only thirteen primary intraosseous ASPS have been reported in the literature. In this study, we report two new cases of this exceedingly rare entity. Both cases already had multiple metastases since diagnosis; one of them represents the first case of a primary bone ASPS in the ulna and is also the primary intraosseous ASPS with the longest reported case of survival, after having maintained long periods of stabilization despite not having received any systemic treatment.