Dedifferentiated primary mediastinal liposarcoma mimicking a thymic tumor.

Mediastinal tumors are heterogeneous and the diagnosis depends on their location in the mediastinum. The most frequent tumors are germinal tumor, lymphoma and thymoma. The clinical and radiological aspects are often not sufficient to orient the diagnosis and biopsy is necessary to confirmed it. Here, we present a rare case of an anterior mediastinal mass incidentally detected in a 63 years old man during assessment for asthma. The lesion was presumptively diagnosed as a thymic epithelial tumor based on location and radiological characteristics. Surgical biopsy revealed a primary dedifferentiated mediastinal liposarcoma with multiple lung metastases.