BACKGROUND: The synchronous or metachronous development of multiple primary soft tissue sarcomas (STS) of different histopathology has been reported only in isolated case reports. METHODS: The records of patients who developed multiple primary STS and who were treated at a tertiary cancer center between 1982 and 2003 were reviewed. RESULTS: Nine patients with multiple primary STS were identified, representing 0.2% of all patients who were treated for STS. The median age of patients at the time of initial presentation with sarcoma was 60 years (range, 51-81 years). Most patients in this series (n = 7) had metachronous development of a second primary STS. The incidence of second primary sarcomas in patients who were diagnosed previously with STS (4.0 per 10,000 population per year) was significantly greater than the incidence of primary STS in the general population (3.2 per 100,000 population per year; P < 0.01). CONCLUSIONS: Although it is an uncommon occurrence, patients who have a history of STS are at an increased risk for the development of a second primary STS.
