Solitary fibrous tumor

A solitarySolitary fibrous tumour tumours (SFT)  is aare a rare neoplasm of mesenchymal origin that comprises less thancomprise < 2% of  allall soft tissue tumours tumours. The majority are benign The majority are benign, although up to 20% may be malignant.⁷

Epidemiology

Intrathoracic SFT usually presents in the  6^th to 7^th decades. Extrathoracic SFT occurs in men and women of all ages equally.⁷.

Location

The majority of solitary fibrous tumours occur in an intrathoraciclocation but up to one third may occur in extrathoracic locations, and as such they may be encountered essentially anywhere, including ⁷:

• pleura (see solitary fibrous tumour of the pleura)
• spinal cord (see solitary fibrous tumour of the spinal cord) ^2-3
• dura (see solitary fibrous tumour of the dura)
• head and neck 
• extremities
• abdominal parenchymal organs,  
• retroperitoneum
• peritoneum
• pelvic organs

Histology

SFT most likely arises from submesothelial fibroblasts and is similar to a haemangiopericytoma.  

At histology, a collagenous matrix with  arrays of spindle cells is usually seen. Areas of necrosis, cystic or myxoid change, calcification, hemorrhage, increased vascularity, atypia, or malignanry may also be seen.^7-8.

RaliographicRadiographic features

CT

CT  reveals a  wellwell-circumscribed,  smoothsmooth, lobulated soft tissue mass that may contain scattered calcifications. Smaller tumors tend to enhance homogeneously, whereas larger lesions may have central tubular or rounded low-attenuation areas due to cystic or necrotic change.

MRI

On MRI, benign  solitary fibrous tumours usually has relatively homogeneous low  to  intermediate-to-intermediate signal intensity  relativerelative to skeletal muscle on  bothboth  T1-weighted imaging and T2-weighted imaging because of fibrous tissue, as well as intense enhancement. 

In addition, there may be areas of subacute haemorrhage that have high T1-weighted signal intensity, as well  as nonenhancingas non-enhancing cystic or necrotic foci that are more heterogeneous and higher in T2-weighted signal intensity relative to  thethe remainder of the tumour.

However, when  a central focus of heterogeneity and variable contrast enhancement is identified in an SFT at CT or MRI, malignant degeneration should be considered.⁷.

Treatment and prognosis

• a benign SFT less than 10cm< 10 cm in size typically has a favorable outcome with surgical resection alone.
• an SFT greater than> 10 cm that also harbors malignant foci, and has positive surgical margins tends to  have a poor prognosis, despite surgical treatment;
  • optimal adjuvant  therapytherapy for the latterthis group is unknown, and close-interval follow-up is advised because there is an increased incidence of local recurrence.