Mature Mediastinal Teratoma.

A teratoma is a tumour with tissue or organ components resembling normal derivatives of more than one germ layer. We present a case of mediastinal mature teratoma as they have a low incidence rate. A 45-year-old female presented with right sided chest pain and paroxysmal attacks of dry cough and fever. A diagnosis of pulmonary hydatid cyst was made on computed tomography (CT) examination. Microscopic study revealed a tumour composed of elements from all the three germ layers. A diagnosis of mature mediastinal teratoma was made which is the second common site for germ cell tumours.