(P 524) PRESENTATION AND OUTCOMES OF EXTRASKELETAL CHONDROSARCOMAS TREATED WITH SURGICAL RESECTION

Objective: Chondrosarcomas are malignant tumors arising from cartilage that typically arise in the skeleton. Rarely, these tumors initially present outside of the skeleton and represent only 2% of sarcomas found in the soft tissues. Due to the rarity of these tumors, there is minimal literature regarding their presentation and outcomes. The purpose of this study is to describe the diagnosis, treatment, and prognosis of these sarcomas.

Methods: A retrospective review of all patients who were diagnosed with an extraskeletal chondrosarcoma at our institution between January 1989 and December 2021 was performed. The patient’s age at the time of diagnosis, sex, site and size of the initial tumor, and subtype of chondrosarcoma was collected. In addition to this, treatment modalities, margin status after surgery and surgical complications were obtained in addition to disease free and overall survival.

Results: A total of 11 patients with 12 extraskeletal chondrosarcomas at presentation were identified with 5 males and 6 females. The average age of the patient was 57 (range 14 to 88) and average follow-up was 6.3 years (range 8.1 months to 26.2 years). The size of the tumors ranged from 3.5 cm to 12 cm with the median tumor size being 6.1 cm. Multiple subtypes were diagnosed, including 8 myxoid, 2 mesenchymal, and 1 dedifferentiated extraskeletal chondrosarcomas. Two patients initially presented with lung metastasis. All patients underwent surgical excision, and 6 patients had positive surgical margins and 5 had negative margins. Eight patients received radiation, 7 (64%) patients had a local recurrence, and 6 (55%) patients developed metastatic disease, with 4 (36%) patients who experienced both a local recurrence and developed metastatic disease. All 5 patients that developed metastatic disease had a tumor arise in their lung with one patient who developed a metastatic disease in the inguinal region. Clinical and disease characteristics are reported in Table 1. The overall survival rate was 77% at 3 years and 64% at 5 years. Progression-free survival rate was 70% at 1 year and 50% at 3 and 5 years, respectively. Radiation therapy had no impact on local recurrence (p=1.0). Margin status had no impact on local recurrence (p=0.55) or development of metastatic disease (p=1.0).

Conclusion: Overall, the location of the initial extraskeletal presentation varied, with the majority arising in the appendicular skeleton, and most being myxoid chondrosarcomas. In this series, margin status did not impact local recurrence or the development of metastatic disease. Further studies are necessary to continue to evaluate the presentation and prognosis of these rare tumors.