A case of primary mediastinal Ewing's sarcoma / primitive neuroectodermal tumor presenting with initial compression of superior vena cava
We describe the case of a 66-year-old no smoking woman admitted to our Hospital with dyspnea for tracheal compression, dysphagia, retrosternal pain and signs of initial extrinsic compression of superior vena cava (SVC).\nA computed tomography (CT) scan showed multiple lymph nodes extended from the left supraclavicular region to the anterior-superior mediastinum, with encasement of the anonymous arch. The patient was initially submitted to CT guided fine-needle aspiration that failed to obtain adequate tissue for cytopathologic evaluation. In this case, diagnosis can be reached with less invasive and cost-effective procedures (i.e. endobronchial ultrasound-guided transbronchial needle aspiration), but due to unavailable of technology for endobronchial ultrasound in our hospital, thoracic surgeon performed diagnostic mediastinoscopy.[] Due to initial signs of SVC, radiotherapy (RT) consultation was required from medical oncologists. Due to the clinical presentation, we planned a primary RT regarding palliation of respiratory symptoms. Before the start of RT we received the result on histopathologic examination that showed small and round blue cells with round nuclei, small nucleoli and scanty cytoplasm. Immunohistochemical analysis revealed positive staining for CD99, vimentin, S-100 and NSE and negative staining for chromogranin A, MELAN-A, thyroid transcription factor-1, DESM, panCK, cytokeratin 7, CK 20 and CEA. Based on these findings, an ES/PNET was diagnosed.\nAfter a multidisciplinary decision-making approach, we delayed the planned RT and the patient received 6 cycles primary chemotherapy in according to Italian Sarcoma Group.[]\nRestaging CT scan after four cycles demonstrated a partial response [ and ]. Chemotherapy was administered with safely profile. After a thoracic surgery consultation, the tumor was considered unresectable.\nOne month after the end of systemic therapy the patient underwent mediastinal three-dimensional conformal RT. Treatment planning was based on CT scan with 5-mm section thickness obtained in the treatment position. Dose-prescription was according to the International Commission of Radiation Unit report 62. The clinical target volume (CTV) and the planning target volume (PTV) were defined using the post-chemotherapy diagnostic CT scan. PTV was obtained with an isotropic expansion of 1 cm of CTV, to include setup error and organ motion. RT was delivered with four individually shaped non coplanar fields to include the entire PTV in the isodose 100% (range, 95%–107%) area, using 6 MV photon beam produced by a linear accelerator (Synergy Platform; Elekta). Total RT dose was 60 Gy administered with daily standard fractionation schedule of 2 Gy.\nThe maximum dose to the spinal cord was 40 Gy, the percentage of total lung volume exceeding 20 Gy (V20) was 23%; the percentage of esophagus volume exceeding 55 Gy (V55) was 59% [ and ].\nRT was well tolerated, with relief of persistent mild dyspnea and retrosternal pain.\nHowever, restaging CT scan performed at one month after RT showed a disease progression and the appearance of multiple intraparenchymal lungs metastases.\nThen, the patient underwent a second line chemotherapy, interrupted for severe hematologic and gastrointestinal toxicity. Following vertigo and mental changes the patient was submitted to a brain MRI that showed multiple supra and subtentorial metastases. Due to the systemic progression, palliative supportive care was prescribed.