Extra-skeletal Ewing sarcoma of the diaphragm in a young female: a case report.

Introduction and importance: Extra-skeletal Ewing sarcoma (EES) belongs to the family of primitive neuroectodermal tumors (PNET) and arises from soft tissue, with only 30 cases reported in the literature until now. Early diagnosis is crucial, and the management requires a multidisciplinary approach for better patient outcomes and survival. Case presentation: A 20-year-old female presented to the surgical outpatient department with complaints of shortness of breath and right lower chest pain. Upon physical examination, a lipomatous lesion was observed. Ultrasound and CT scan showed a heterogeneously enhancing soft tissue mass in the right lower hemithorax causing erosion and osteolysis of the right 9th rib, involving intercostal muscles, and exerting mass effect on the underlying hemidiaphragm. Later USG-guided Tru-cut biopsy was performed to confirm the diagnosis, which reported Ewing sarcoma with CD 99, FL-1, and NKX 2.2 positive. En-bloc tumor resection along with a portion of the diaphragm was performed, and a tube thoracostomy was carried out. Chest wall reconstruction was done with mesh and a local muscle rotation flap cover. Adjuvant chemotherapy was initiated. Clinical discussion: EES often presents with vague symptoms such as shortness of breath or abdominal or chest pain, thus making the diagnosis even more difficult. However, it has a relatively poor prognosis and thus is an important differential to rule out. Conclusion: Extra-skeletal Ewing Sarcoma is a highly aggressive tumor that requires prompt diagnosis and treatment, with surgical resection being the first line of treatment. Adjuvant chemotherapy has also shown better outcomes.