Solitary fibrous tumors (SFT) represent a rare entity of soft tissue tumors which are exclusively located in the thoracic cavity as pleural fibrous tumors. Extrathoracic SFT in the soft tissues are very rare. We analyzed the oncologic outcome of the soft tissue SFT.

Between January 2009 and December 2014, we treated 6 soft tissue SFT cases. Patients' clinical data, magnetic resonance imagings and pathologic findings were reviewed.

The patients included two women and four men. The average age of the patients was 45 years (range, 32-56 years). The mean tumor size is 7.2 cm (range, 3.5-13.0 cm). One patient received wide excision of the tumor and remaining 5 patients marginal excision. After the excision, pathologic report confirmed that 4 patients showed margin positive. However, no patient received further surgery or adjuvant treatments. After the immunohistochemistry, 2 out of 6 patients identified as malignant soft tissue SFT. The mean follow-up period was 25.8 months (range, 6-66 months). Although 4 patients revealed margin positivity, no subsequent local recurrence or distant metastasis was observed.

Since the SFT are categorized as intermediated biological potential with a low risk of metastasis and recurrence, marginal excision can be a one of the surgical options for these tumors which are located adjacent to vital structures. However, close observation is needed because local recurrence can be significantly higher the patients with positive resection margins.