Clinical features of bone and soft tissue tumors of the foot and ankle: Results from a retrospective single-center case-series.

BACKGROUND: The malignant potential of the musculoskeletal tumors of the foot and ankle has often been underestimated because of their rarity. The current study reviewed the clinical features of the tumors of the foot and ankle, and evaluated the tumor size via imaging-based analysis to distinguish between benign and malignant lesions.

METHODS: A retrospective review was performed using the clinical records of all patients with histologically confirmed musculoskeletal tumors of the foot and ankle, treated between 1998 and 2020 at our institution. We examined the distribution of tumors, rate of unplanned excision for primary surgery, and subsequent outcomes. In addition, the tumor size was examined via magnetic resonance imaging, and the cut-off value was determined via receiver operating characteristic (ROC) curve.

RESULTS: A total of 103 bone and soft tissue tumors of the foot and ankle were included, of which 78 were soft tissue tumors and 25 were bone tumors. Of the 14 cases of malignant bone and soft tissue tumors, 6 (42.9%) received unplanned excision in the primary surgery, followed by amputation in 3 cases. Tumor size of malignant soft tissue tumors was significantly larger than that of benign soft tissue tumors (47.6 mm vs. 31.0 mm, respectively, P < .001). However, the difference between benign and malignant bone tumors was not statistically significant with the numbers available. ROC curve determined that the optimum diagnostic cutoff value for soft tissue tumor size was 40 mm, with a high area under the ROC curve 0.816 (95% CI: 0.711-0.921, sensitivity 91.7%, specificity 70.5%) CONCLUSIONS: We highlighted that bone and soft tissue tumors of the foot and ankle were often misdiagnosed and initially inadequately treated. We suggest that a cutoff value of 40 mm may be a useful index for prediction of malignancy in soft tissue tumors of the foot and ankle.

LEVEL OF EVIDENCE: Ⅲ.