A 36-year-old man presented with a pleural tumor. The first pathologic analysis diagnosed biphasic pleural malignant mesothelioma. However, the atypical clinical course, the early development of lung metastases and a new reading of histologic documents led to the diagnosis of primary pleural synovial sarcoma. The literature review is limited, as only nine other cases have been reported to date. Chest pain is the only constant clinical feature. Misleading interpretation of histologic material is frequent (6 of 10 cases). Only a complete immuno-histochemical study confronted with the clinical course can lead to the correct diagnosis. Because the efficacy of chemotherapy and/or radiotherapy is poor, surgery remains the basis of treatment, whenever possible. Evolution is mainly intra-thoracic, with multiple local recurrences and lung metastases. Prognostic is poor, a survival rate is similar to that of primary pulmonary sarcomas.