Pleuropulmonary blastoma in a young adult presenting as a ruptured cystic teratoma in radiology.

Pleuropulmonary blastoma (PPB) is a rare malignant dysontogenetic neoplasm primarily affecting children and is characterized histologically by a variably mixed blastematous and sarcomatous patterns. We herein report a very exceptional adult case of PPB. A 21-yr-old male patient presented with a left chest pain of two weeks' duration. A computed tomography scan revealed a large, multicystic tumor occupying the left lower hemithorax, leading to the impression of a ruptured mediastinal cystic teratoma. A thoracotomy for resection of the tumor was performed. On histologic examination, the tumor consisted of cystic walls and associated solid lesions which showed undifferentiated blastemal tissues with focal fibrosarcomatous and rhabdoid features. Immunohistochemically the tumor cells only showed diffuse strong positivity for vimentin. The histologic findings corresponded to a type II PPB. The authors suggest that PPB, especially of type I or II, should be included in the radiologic differential diagnosis of mediastinal cystic neoplasms in a young adult.