Primary pulmonary synovial sarcoma: A clinicopathological study of 22 cases

According to the World Health Organization (WHO) classification, synovial sarcoma is a malignant tumour of uncertain differentiation. Primary pulmonary/ pleuropulmonary synovial sarcoma (PPSS) is similar to the soft tissue SS but arises from the lung parenchyma, tracheobronchial tree, pulmonary artery and pleura mainly (genuine PPSS) and comprises 0.1%-0.5% of all lung neoplasms.1-3 It may also include SSs that arise from the chest wall, heart, mediastinum and hemithorax.2-3 Primary intrathoracic SSs, as well as Primary pleuropulmonary and mediastinal SSs (PPMSSs), are the other terms used for the same anatomic subset of SSs which loosely encompass the above-mentioned regions.3-5 There are two major histological subtypes of SS: monophasic (spindle or epithelial) and biphasic. Poorly differentiated areas were defined by the presence of in part or entirely of densely cellular proliferation of primitive round to spindled cells displaying severe nuclear atypia, necrosis and high mitotic activity (> 15/10 HPF) or large epithelioid cells with prominent nucleoli or epithelioid cells with rhabdoid change.6-9 The French Federation of Cancer Centers Sarcoma Group grading system (FNCLCC) was used to grade synovial sarcoma.13 Immunohistochemistry (IHC) The IHC archival slides that were reviewed had been carried out using the Ventana Benchmark XT (Ventana Medical Systems, Tucson, AZ, USA). Real time and Reverse transcription polymerase chain reaction (RT-PCR) Molecular studies were performed on eleven cases (11/22 cases) by RT-PCR for the detection of the common translocations (SYT-SSX1/ SYTSSX2).