186 RARE CASE OF A GIANT THYMIC CYST: A CHALLENGING DIFFERENTIAL DIAGNOSIS OF A PARACARDIAC CYSTIC LESION

Abstract Background Benign thymic cysts are a rare clinical entity, representing approximately 3% of all mediastinal masses. Thymic can be congenital or acquired. We describe case 58-year-old female with giant benign cyst which entered in differential diagnosis pericardial and effusion. Case presentation A was brought to our hospital due new onset dyspnoea fatigue. She had history liquid mass accidentally discovered 9 years before interpreted at that time as loculated effusion (Fig. 1). An echocardiogram performed showed increased size the known lesion without any signs hemodynamic compromise 2). magnetic resonance voluminous originated from anterior mediastinum, extending caudally diaphragm maximum dimensions on right hemithorax 16×12×9 cm (antero-posteriorly, transversely cranio-caudally respectively) 10×5×13 left 3). It initially cyst. All findings were then collegially reviewed for first it suspected being cyst, especially its spatial distibution growth over time; particular cranio-caudal both hemithoraxes suggested might have thymus gland then, by force gravity, extended downword bilaterally. The surgically removed using unilateral thoracoscopic approach. Histological examination confirmed origin excluded malignancy. At three month follow up, patient presented no symptoms, normal. Discussion echocardiographic features not lesion-specific, so location used diagnosis. Computed tomography has best resolution, while better capacity differentiate content when is homogeneous lesion. In case, distribution and, particular, nine crucial hints suspect Indeed, sole evaluation last imaging exam would made more problematic because huge dimensions, exact site very challenging identify. Conclusion Our example extremely difficult other paracardiac cystic lesions required integrated discussion team experts different specialties make correct