A Diagnostic Challenge: Retroperitoneal Extraskeletal Ewing Sarcoma with Subaortic Growth and Partial Aortic Encasement Presenting with Nephrolithiasis-Like Symptoms in a Middle-Aged South Asian Male.

Ewing sarcoma is an atypical and aggressive bone malignancy, most commonly observed in the pediatric population. Looking at epidemiological data shows that individuals of Caucasian descent are most susceptible to the disease, which additionally show a slight male predominance. We present the case of a 46-year-old male of South Asian descent who came into an outpatient clinic complaining of ongoing pain in the left posterior flank. The clinical picture initially raised suspicion for recurrent Nephrolithiasis because of the patient's previous medical history. The patient was advised to get a CT scan when imaging revealed a 7cm unidentified mass in the left retroperitoneum. The mass appeared to be developing under the sub aorta and was partially encasing it. Due to the conclusive findings, the patient proceeded to get sampling done by a pathologist. Pathologic examination identified small round blue cells, a key identifier and comparable biologic characteristics of Ewing's Sarcoma. This case emphasizes the diagnostic and clinical significance of encountering a destructive malignancy, specifically Extraskeletal Ewing's Sarcoma; such as anatomical site, patient age group, proximity to vital body structures, and ethnic group. Factors that challenge the traditional scope of Ewing's Sarcoma and the importance of widening diagnostic perspective.