P424 MEDIASTINAL ROUND CELL SARCOMA WITH PULMONARY ARTERY STENOSIS: CLINICAL USEFULNESS OF CARDIAC MRI IN CARDIO–ONCOLOGY

Abstract

Abstract Case description: a previously healthy 26–year–old man presented with dyspnea on exertion and dry cough. CT scan revealed a large mediastinal mass with displacement of great vessels and trachea and pericardial effusion. Cardiac MRI showed the huge mediastinal mass, literally leaning on the heart with signs of compression of the pulmonary artery (Figure 1) with the typical D–shape of inter ventricular septum. Pericardial effusion did not compress the RV due to high intraventricular pressure. At baseline echo the mass simulated pulmonary artery stenosis as a consequence of pulmonary artery “ab extrinseco” compression. Surgical biopsy showed Ewing sarcoma lately redefined into undifferentiated round cell sarcoma so the patient started chemotherapy with VAI (vincristine, adriblastine, and ifosfamide) x6 followed by maintenance etoposide and ifosfamide (no anthraciclines for risk of cardiac toxicity). After induction phase MRI showed a partial response to treatment; mediastinal mass further reduced at the end of maintenance (Figure 2). Pericardial effusion disappeared and peak velocity of pulmonary artery went back to normal level at echo. Our patient underwent surgery with en–block removal of mediastinal mass with pericardium and anonymous vein and partial pulmonary upper left lobe resection with R0 resection. Pathology report confirmed an undifferentiated round cell sarcoma (possible embryonal origin, FISH analysis for EWS/FUS genes and 12p negative). Adjuvant mediastinal radiotherapy was delivered. The patient is alive without disease recurrence at one–year follow–up. Conclusions cardiac MR offer great tissue characterization (differential diagnosis between malignant and benign masses) inside/outside the heart. CMR is non–invasive/non radiation and ideal technique for surgery indication and follow–up imaging.