Blue Cell Tumour at Unusual Site: Retropritoneal Ewings Sarcoma.

Ewing's sarcoma is a highly malignant tumour of osseous or non-osseous origin, tremed as extra-skeletal Ewings sarcoma if arising from soft tissue. It is rare occurrence tumor most commonly occurring in paravertebral area, chest wall, head & neck and retroperitoneum. Reporting an interesting case of retroperitoneal Ewing's sarcoma in 39 years old female. Patient had complains of abdominal discomfort & vague pain since 2 months, following weakness in lower limb and loss of weight. On detail history and examination she was further referred to detail pathological and radiological investigations. Haematological profile, renal function test and liver function test were in normal limits. USG abdomen was normal, MRI showed a mass in pelvis retroperitoneum measuring 10x10cms, bilateral ovaries and tubes were normal. Because of retroperitoneal nature of tumor and suspicion of uterine sarcoma, laparotomy was performed. The large retroperitoneal mass adherent to posterior of uterus was excised and send for histopathological diagnosis. On gross and microscopy examination the diagnosis of blue cell tumor with PAS positivity, possibility of extraskeletal Ewing's sarcoma/primitive neuro-ectodermal tumor was made which was further confirmed by immunohistochemistry, positive for S100, Vementin and CD99 and negative for desmin and CK. Confirmed diagnosis help in accurate management and improves survival rate.