Posterior mediastinal Ewing sarcoma with multiple metastases on FDG PET/CT: a rare entity

Abstract Background Ewing sarcoma and peripheral primary neuroendocrine tumors are aggressive neoplasms which consist of small, round, blue cells neuroectodermal origin. They usually arise from the skeleton genetic mutations EWSR1 in chromosome 22 FL1 gene on 11. Extraskeletal sarcomas (EES) rare entities with most common sites EES being extremities, head neck region retroperitoneum. Posterior mediastinal is rare. For its evaluation, 18F-fluorodeoxyglucose positron emission tomography (18F FDG PET/CT) plays significant role staging, management planning prognostication. Case presentation We describe a case posterior mediastinum 20-year-old boy who presented signs upper motor neuron lesion below D10 level. Contrast-enhanced magnetic resonance imaging (CEMRI) showed heterogeneously enhancing mass pre- paravertebral intraspinal extension D2-D4 levels. Fluorodeoxyglucose PET/CT metabolically active occupying superior, middle left, displacing trachea esophagus toward right side causing complete collapse left lung. Posteriorly was seen destroying D2-D5 vertebrae at Metabolically metastatic disease pleura, skull, D12 vertebra, iliac bone bilateral proximal femorae. Biopsy obtained lung adjacent pleura features round cell tumor positive for NKX 2.2, weak FLI 1 negative PAN CK, LCA, Vimentin TLE-1, suggestive sarcoma. Based these investigations, diagnosis made. Conclusion entity. Management comprises radiotherapy systemic chemotherapy reduces burden micrometastasis. However, response to treatment poorer than localized overall 5-year survival rates less 30%. can be useful tool accurately detect extent local presence atelectasic as well evaluating therapy.