We report on the case of a 45-years old woman with repeated pleural effusions lasting for 2 years. She had a history of breast carcinoma 6 years ago, which was treated by breast amputation and radiation. After repeated histological and cytological examinations no tumorous compromise of the pleura or other cause for the effusions could be found. A pleural resection was performed. On the histological and electron microscopical examination deposits of a foreign substance were found, which was identified as polyvinylpyrrolidone. This substance was obviously introduced in the pleural cavity by the attempts to treat the effusions by pleurodesis with Diclofenac and Tetracycline (Vibravenös). The diagnosis is suggested by the histological findings, but it must be confirmed by anamnesis, also for PVP deposits in other organs.