Primary mediastinal synovial sarcoma with subsequent development of primary adenoid cystic carcinoma of lung presenting as superior vena cava syndrome.

Primary mediastinal sarcomas are aggressive tumors with a very rare incidence. This report describes the case of a 35 year old male patient who presented with acute symptoms of dyspnoea, facial puffiness, engorged neck veins and hoarseness of voice. With the clinical picture consistent with the superior vena caval (SVC) syndrome, the patient was investigated with computed tomography of the chest. This revealed a large soft tissue density mass lesion compressing the SVC along with other critical superior mediastinal structures. Histopathological evaluation of the mass revealed features consistent with a soft tissue sarcoma and positive staining was observed for vimentin and S-100. Cytogenetic analysis by fluorescent in-situ hybridization (FISH) demonstrated the t(X: 18) translocation. Thus diagnosis was established as primary mediastinal synovial sarcoma. Patient was treated with three-cycles of neo-adjuvant (ifosfamide 2400mg/m2 on days 1-5 and doxorubicin 37.5 mg/m2 on days 1 & 2) chemotherapy, to which there was a partial response as per the RECIST criteria. Surgical excision of the mediastinal mass was performed, and further post-operative treatment with adjuvant chemo-radiotherapy was provided. Patient was under regular surveillance at our clinic and remains free of symptoms one-year after treatment completion. But after 14 months of treatment completion patient again had symptoms of progressive dyspnea, hoareness of voice and mild facial puffiness over a period of 2 months. On further investigating he was found to have right-sided centrally located mass with cystic and necrotic changes with extension and compression of trachea, SVC, right upper lobe bronchus and its branches. Histopathological examination of the biopsy from the lesion revealed adenoid cystic carcinoma of the lung. Rest of the metastatic work up was within normal. Immunohistochemistry of the specimen revealed c-Kit positivity. In view of the morbid second surgery he was put on Imatinib 400mg once a day and celecoxib 200mg twice a day. After 4 months patient had partial response and presently continuing with the same regimen. Extensive literature search didn't reveal much information on combined primary mediastinal sarcoma and adenoid cystic carcinoma of lung.