Clinical outcomes of extra-thoracic solitary fibrous tumours

Extra-thoracic solitary fibrous tumours (ESFTs) have traditionally been regarded as indolent neoplasms similar to their intra-thoracic counterparts. However there has been some evidence that a subset of more aggressively malignant tumours exist. We examined our experience with these rare tumours in an effort to clarify their clinico-pathological behaviour and relate this to their histopathological findings.

All patients with a histopathological diagnosis of solitary fibrous tumour (SFT) who presented to the Royal Marsden Hospital between 1998 and 2006 were reviewed. Clinico-pathological data were recorded for all cases and subset analysis performed to compare rates of locoregional recurrence, distant metastases and death.

There were 33 cases included in the study. 18 cases had malignant features on histological examination. Locoregional recurrent disease was more common in those with malignant histopathological findings compared to those with benign histopathology (6/18 vs 0/15 p 0.021). Distant metastatic disease was more common in those with malignant histopathological findings (7/18 vs 1/15 p 0.046) and these patients were at increased risk of death (10/18 vs 0/15 p<0.01). The presence of malignant histopathology was the only factor to affect survival with no benign cases dying of disease and malignant cases having a median survival of 59 months (p 0.003).

In our experience ESFTs have a higher rate of malignant behaviour than that classically described. Those tumours with atypical or malignant features on histological examination have poor prognosis and should be managed and followed up in the same manner as other high-grade soft tissue tumours.