Mediastinal teratoma: two case reports.
Teratomas in the mediastinum arise from pluripotent cells and are composed of a wide diversity of tissues originating from three germ layers ectoderm, mesoderm and endoderm. Hence we get all tissues represented in the mass, for example, epithelial and endodermal cysts lined by the squamous and collumnar cells respectively. It also has mesodermal elements, like tooth, bone muscle, etc. Benign teratomas are usually slow growing and give minimal symptoms and are often discovered when a routine chest x-ray is done. They are well circumscribed and usually removed without much difficulty. Malignant teratomas are fast growing, often cause pressure symptoms early and are diffuse. Diagnosis is done at thoracotomy and often only biopsy is possible. These tumours enlarge rapidly and fatal in six to twelve months after the diagnosis is established. Malignant teratomas of testes, seminoma, have better prognosis, compared to mediastinal lesions. Both types of teratomas also occur in ovaries. Two cases of benign mediastinal teratomas are presented. They were treated by thoracotomy with good results.