Primary Pleural Leiomyosarcoma – A Diagnostic Challenge

Primary pleural malignancy is uncommon accounting for 0.3-3% of all thoracic tumours. Of these, 90% are malignant mesotheliomas with pleural smooth muscle tumors being exceptionally rare. We present a case of pleural leiomyosarcoma as a second malignancy in a 58 year old ex-smoker who had been previously treated for mucinous adenocarcinoma colon. The pleural tumor presented as acute onset symptomatic left sided pleural effusion and was confirmed by light microscopy and immunohistochemistry of thoracoscopic pleural biopsy. To the best of our knowledge, primary pleural leiomyosarcomas have been described in less than 10 case reports in the past, and this is the first such case of pleural sarcoma involving multiple primary malignancies. This case is being reported to increase awareness about this uncommon clinical entity.