Anterior mediastinal mature teratoma focally infiltrating pulmonary parenchyma.

Abstract

Teratomas are germ cell tumors. Mediastinum is the second most common extra-gonadal site of these tumors.[1-3] Mediastinal masses in children and ado-lescents are usually considered malignant. Even be-nign teratomas have been reported to transform to malignant ones in case of delayed diagnosis or presentation.[3-5] Moreover, large mediastinal teratoma without any long-term symptomatology is quite rare. We describe here a large anterior mediastinal mature teratoma diagnosed in a paucisymptomatic adolescent. A 15-years-old girl was admitted for a two-days-long history of low-grade fever associated with acute-onset of cough and mild thoracic pain. Pain was re-ferred to the left hemithorax and increased with breathing and movements. Vital signs were normal, with a room-air oxygen saturation level of 99%. Physical examination was unremarkable, particularly with normal breath sounds at chest auscultation. Unexpectedly chest x-ray revealed a large homoge-neous mediastinal paracardiac mass in the left hemithorax (Fig. 1). Echocardiogram showed normal cardiac function with mild pericardial effusion. Con-trast enhanced computed tomography (CT) scans confirmed a well-demarcated mediastinal partially cystic mass of about 11x9x8 cm with regular bor-ders, completely enclosing the thymus and contain-ing soft tissue, fat and a small calcification (Fig. 2,3). The mass mildly compressed the adjacent struc-tures. There were no radiological signs of invasion into the surrounding mediastinal structures. These radiological findings were consistent with the diag-nosis of cystic teratoma. Biochemical evaluation showed lymphocytosis with neutrophilia (white blood cell count 15,240/mm3, neutrophils 67%) and in-creased ESR (67 mm/1sth). Alpha-fetoprotein and beta human chorionic gonadotropin were within normal limits. At left postero-lateral thoracotomy, the mass occupied the anterior mediastinum and focally infiltrated pulmonary parenchyma of the inferior lobe of the left lung. The mass and the infiltrated part of the inferior lobe of the left lung were totally excised. Histopathological analysis confirmed the diagnosis of mature cystic teratoma without immature elements. Chemotherapy was not administered. After a one-year of clinical, biochemical and radiological follow-up no recurrence of disease was evident. Long term follow-up is in plan.