Extra-Skeletal Ewing Sarcoma: A Diagnostic Dilemmas

Inguinal swellings usually occur as a result of inguinal hernia, lymphadenopathy, granuloma inguinale, femoral hernia, hydrocele of spermatic cord, ectopic/undescended testis. Soft tissue sarcomas comprise most common malignant tumours of the groin. We report an interesting case an inguinal swelling, which was evaluated and initially diagnosed as malignant Extra gastrointestinal stromal tumour (e-GIST), operated to be finally reported as Extra skeletal Ewing sarcoma. This case is being reported for its rarity in occurrence, rarity in such a presentation and for the diagnostic misinterpretation following the initial biopsy. We present a case of a 49-year-old gentleman presented with a painful swelling over the right inguinal region for 1 week, with gradual increase in size. Examination revealed a tender, firm swelling above right inguinal crease with a smooth surface. Ultrasound was suggestive of lymph-nodal mass, CECT revealed a giant soft tissue sarcoma in the pelvis involving anterior vesical and para-vesical spaces, extending into right inguinal canal along the spermatic cord. Biopsy was suggestive of malignant Extra-Gastrointestinal stromal tumor (E-GIST). Following a multidisciplinary team discussion, exploratory laparotomy with right orchidectomy was performed. Histopathology of the operative specimen was suggestive of Extra skeletal Ewing Sarcoma. It is because the immuno-histochemical expression of epithelioid GIST could mimic that of Ewing sarcoma’s, there was an oversight in arriving at an accurate diagnosis. One must be vigilant that there might be a discrepancy between initial diagnosis on biopsy and the final diagnosis on histopathology and IHC, in especially in such rare tumours.