Ewing’s sarcoma of the right kidney with multiple metastasis on PET/CT

Abstract

Abstract Background Ewing’s sarcoma is categorized as small round cell aggressive tumor which commonly occurs in bone and soft tissue. Primary renal Ewing’s sarcoma is an extremely rare entity and accounts for less than 1% of renal masses. It is characterized by a very aggressive course, with very few reported cases in the literature. Primary renal Ewing’s sarcoma is indistinguishable from renal cell carcinoma on anatomical imaging and therefore need histopathological correlation for confirmation. The positron emission tomography (PET) fused with computed tomography (CT) helps in the evaluation of disease, for staging and metastatic workup. Case presentation We present a case of 48-year-old lady who presented to urology department with difficulty in passing urine for 5 months associated with pain in the right flank region. She had an episode of haematuria 5 months back. Contrast enhanced CT showed a large lobulated heterogeneously enhancing right retroperitoneal mass in renal fossa. Histopathological examination and immunohistochemistry were suggestive of Ewing’s sarcoma. The PET/CT revealed FDG avid right renal mass with lymph nodal and skeletal metastasis. Conclusions Ewing’s sarcoma being aggressive tumour usually present with bone, liver and lung metastasis along with lymph nodal metastasis at time of diagnosis. The 18 F FDG PET/CT helps in diagnosis, staging, appropriate treatment planning, restaging, response evaluation and prognostication of Ewing’s sarcoma.