Multiple recurrent malignant solitary fibrous tumors: long-term follow-up of 24 years.

Solitary fibrous tumor (SFT) of the pleura is a rare, generally benign, neoplasm that accounts for less than 5% of all pleural tumors. However, 10% to 30% of SFTs display aggressive behavior with local recurrence, malignant transformation, and distant metastasis. We report a case of multiple recurrent SFTs of the thorax in a 77-year-old Korean woman. During a 24-year period, she underwent six surgical resections for six recurrent SFTs. The tumor eventually underwent morphologically malignant transformation. This unique case highlights the necessity of long-term follow-up in cases of SFT because of the potentially malignant biological behavior of this type of tumor.