Solitary fibrous tumour presenting with a single bone metastasis: report of six cases and literature review.

Vittoria Colia,Salvatore Provenzano,Paolo G Dagrada,Andrea Marrari,Angelo Paolo Dei Tos,Claudia Sangalli,Paola Collini,Silvia Stacchiotti,Salvatore Lorenzo Renne,Paolo G Casali,Carlo Morosi

doi:10.1186/s13569-016-0055-1

Abstract

BackgroundSolitary fibrous tumour (SFT) is a rare soft tissue sarcoma with a low metastatic potential. A higher metastatic rate is observed in the high-grade/dedifferentiated variant. The most common expected site of distant spread are the lungs and the liver. Bone involvement is generally viewed as a late stage of disease spread. We report on a retrospective series of SFT patients relapsing with a single distant bone recurrence as first metastatic event, without evidence of other organ involvement.Case presentationAll patients affected by a single distant bone metastasis from SFT as first distant event, without any evidence of other site of metastasis, observed at our Institution, were considered. Bone involvement from SFT was pathologically assessed in all cases and confirmed by expert pathologists. A total of six patients were retrospectively identified. Primary tumour arose from the meninges in four patients, from soft tissues in two. Bone metastases were located to the vertebrae, the hip, the acetabulum and the rib. In all cases, bone relapse was the first event, with one patient presenting a local relapse. Median time from the primary tumour and the evidence of bone relapse was 40 months (range 0–58). In 2/6 patients bone metastasis was treated with radiotherapy (RT), in 2/6 with surgery, in 2/6 with surgery plus RT. At a median follow-up of 55 months (range 23–88), 5/6 patients are alive (2/5 without disease, 3/5 with multicentric metastatic disease) and one is dead of disease. 2/6 patients did not relapse after the treatment of the bone metastasis.ConclusionsThis small series in a relatively rare histology suggests that isolated, possibly late, bone metastases are a plausible scenario, in particular in meningeal SFT. Notably, new bone lesions in a patient with a history of SFT should be always investigated. Exclusive local treatments may be an option, though collection of such series would be needed to define the best treatment strategy.

Highlights

Solitary fibrous tumour (SFT) is a rare soft tissue sarcoma with a low metastatic potential
SFT is characterized by a specific NAB2–STAT6 gene fusion which is responsible for the nuclear expression of the chimeric oncoprotein STAT6, which is the immunohistochemical hallmark of SFT [5,6,7,8] and helps in differential diagnosis
We report on a retrospective series of SFT patients who suffered from a single distant bone recurrence as their first metastatic event, without evidence of any other organ involvement

Summary

Conclusions

This small series in a relatively rare histology suggests that isolated, possibly late, bone metastases are a plausible scenario, in particular in meningeal SFT. New bone lesions in a patient with a history of SFT should be always investigated. Exclusive local treatments may be an option, though collection of such series would be needed to define the best treatment strategy

Background

Discussion

Conclusion