Calcaneal Ewing's Sarcoma With Skip Metastases to Tarsals and Lymph Node Involvement: A Case Report.

Ewing's sarcoma (ES) represents the second most common primary malignant tumor of bone of children and occurs rarely in the bones of the foot. Dissemination to regional lymph nodes and skip metastases to adjacent bones are thought to be uncommon. We report a case of a 19-year-old female with the diagnosis of ES of the right calcaneus. Six months earlier, she had presented to the hospital with a history of ankle sprain and was treated with analgesics and ice application. Despite the treatment, the pain over the ankle persisted, her foot swelled progressively, and a mass evolved on the lateral side of the foot. She was referred to our clinic for further treatment options. Radiography and magnetic resonance imaging revealed an expansile mass originating from the calcaneus with talar and cuboidal skip metastases, with concomitant popliteal and inguinal lymph node involvement. The diagnosis was confirmed by histopathologic evaluation after Tru-Cut biopsy. Below-the-knee amputation with popliteal and inguinal lymph node dissection was performed after neoadjuvant chemotherapy. The postoperative first-year follow-up data for the patient showed no evidence of metastasis. The calcaneus is a rare location for the development of ES. A few patients with ES will present with skip metastases to adjacent juxtaarticular bones or regional lymph node involvement. Therefore, the present study has presented a unique case of ES with a rare anatomic location and an unusual metastatic pattern.