Extraskeletal Ewing's sarcoma of the thigh with lung and bone metastasis: Case report.

INTRODUCTION AND IMPORTANCE: Extraskeletal Ewing's sarcoma is an uncommon tumor with a devastating prognosis and a very high mortality rate, particularly in metastatic forms, it primarily affects young people mainly in the 2nd to 4th decades of life. It can affect different parts of the body, without a particular clinical presentation which delays diagnosis.

CASE PRESENTATION: 12-year-old male patient presented with swelling over the left proximal thigh of 7 months duration associated with pain and limping. On physical examination, he had about 20 × 15 cm firm, tender, and erythematous proximal left thigh swelling that is fixed to the structures with an overlying scar.

CLINICAL DISCUSSION: Extra skeletal Ewing's sarcoma (EES) is a member of the Ewing Sarcoma Family of tumors. EES is a rare tumor with an incidence ranging from 0.1 to 0.4 per a million people. It presented with rapidly increasing swelling mainly over the soft tissue of the proximal thigh, pelvis, paravertebral region, chest wall, upper arm and shoulder. Age at presentation ranges 10 to 30 years with no gender preference. Imaging is crucial in the diagnosis, preoperative assessment, in staging and evaluation of treatment outcomes. Histopathology study is mandatory for the definitive diagnosis of EES among competitive differential diagnoses. The management of EES includes Surgery, chemotherapy and/or radiation therapy based on the stage of the disease.

CONCLUSION: EES is a rare tumor but it should be in the differential diagnosis of adolescent patients presented with soft tissue mass/swelling.