Myxoid solitary fibrous tumor with rapid growth due to increased mucinous components: a case report

Background Myxoid solitary fibrous tumors are defined as solitary fibrous tumors with ≥ 50% mucinous components. As they are a rare type of pleural tumor, no reports on their rapid growth before surgery exist. Case presentation Herein, we report the case of a 63-year-old male patient with a myxoid solitary fibrous tumor. The tumor had grown rapidly from 27 to 50 mm over 6 months, and a contrast-enhancing area was observed in approximately one-quarter of the tumor on computed tomography. The tumor was located in the parietal pleura at the ventral part of the left fourth intercostal space without adhesion or invasion into surrounding organs. It was completely resected via video-assisted thoracic surgery. Based on histopathological and immunohistochemical findings, the tumor was identified as a myxoid solitary fibrous tumor. The patient was discharged on postoperative day 2 and has had recurrence-free survival for 6 months postoperatively. Conclusions To the best of our knowledge, this is the first case to report the rapid growth of myxoid solitary fibrous tumor despite its predominantly benign nature. Myxoid solitary fibrous tumors should be considered in the differential diagnosis of rapidly growing preoperative tumors.