Abstract

Introduction: Solitary fibrous tumours (SFTs) are rare spindle cell neoplasms and have been described according to location as intra-thoracic and extra-thoracic. The World Health Organization classifies SFT as having intermediate malignant potential with low risk of metastasis. Initially extra-thoracic SFTs (ESFT) were considered to be benign with lower rates of mortality when compared to their thoracic counterpart.  However, more recent series have found that ESFT behave more aggressively than previously thought. Our tertiary referral centre for soft tissue sarcoma has seen a significant proportion of aggressive disease associated with ESFT.

Methods: A review of all patients with a pathological diagnosis of ESFT was carried out between 2006 and 2019. Histopathology data was reviewed and a database was created to record patient demographics as well as follow up data including recurrence, metastases and survival. Statistical analyses were carried out.

Results: A total of 95 patients were reviewed of which 75 had both biopsy and resection data. 29% of tumours were classified as malignant (MSFT) and 71% tumours were classified as benign (ESFT) after resection. We noted that 50% for patients with MSFT were initially benign ESFT on initial biopsy.

Conclusion: Our study showed that 50% of biopsies for patients with MSFT were initially benign and we feel this has important surgical considerations. Certain prognostic factors are important to help risk stratify these patients. We would recommend that patients with ESFT should be kept under surveillance in a manner similar to patients with malignant soft tissue sarcomas.