Background: Extraskeletal myxoid chondrosarcoma (EMC) is a rare soft tissue sarcoma. Although it has been regarded as a low-grade sarcoma unassociated with tumor-related death, a recent study has suggested an insidious nature with a high propensity for relapse during a long disease course. The aim of this study was to clarify the long-term clinical features of EMC treated at a single referral center using state-of-the-art techniques.
Methods: A retrospective review of 23 consecutive patients (10 males, 13 females; mean age 58 years) treated between 1979 and 2008 (mean follow-up; 109 months) was performed.
Results: Surgery for the primary tumor was performed in 22 patients, and 7 cases recurred locally due to inadequate resection. Eleven patients had metastatic disease, either at diagnosis (3) or developing later (8). The 5/10-year overall survival rates were 91/84 %, and the 5/10-year local recurrence-free and metastasis-free survival rates for patients with localized disease were 89/62 and 89/61 %, respectively. Larger tumor size (>10 cm) and metastases at diagnosis were significant negative prognostic factors. Four patients received ifosfamide-based chemotherapy with no objective response. There was no local recurrence in three patients who underwent R1 resection followed by adjuvant radiotherapy. Clinical palliation and retarded progression of the metastatic disease were achieved in three patients who underwent radiotherapy.
Conclusions: EMC is indolent but has a high propensity for relapse over 5 years of follow-up. Definitive initial surgery and careful monitoring for a prolonged period are important. Radiotherapy seems beneficial in an adjuvant setting and as palliative therapy for metastatic disease.