Solitary fibrous tumor

Solitary fibrous tumours (SFT) are a a rare neoplasm of of mesenchymal origin that comprise <less than 2% of all soft soft tissue tumours tumours. The majority are benign majority are benign, although up to 20% may be malignant.

For a discussion of specific presentations of SFT, please refer on: to

• solitary fibrous tumour of the pleura
• solitary fibrous tumour of the spinal cord
• solitary fibrous tumour of the dura

Epidemiology

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

Clinical presentation

Although typically asymptomatic asymptomatic, it  may  present with symptoms symptoms and signs related related to extrinsic compression of  adjacent organs. Rarely solitary fibrous tumours result innon-islet cell tumor hypoglycemia (NICTH) as a result of secretion secretion of insulin-like growth factor-2 (IGF-2) ^4-7,11. Rarer still is acromegaly ¹¹. 

Pathology

Location

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

• pleura
• spinal cord^2-3
• dura
• head and neck 
• extremities
• abdominal parenchymal organs
• retroperitoneum
• peritoneum
• pelvic organs organs

Histology

SFT most likely arises from submesothelial fibroblasts and and used to to be included inhaemangiopericytoma spectrum ¹⁰.  

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

Radiographic features

CT

CT  reveals a well-circumscribed, smooth, lobulated soft soft tissue mass that may contain scattered calcifications. Smaller tumors tend to enhance homogeneously, whereas larger larger lesions may have have central tubular or rounded 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 signal intensity relative to skeletal muscle on both  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 well as non-enhancing cystic or necrotic foci that are more heterogeneous heterogeneous and higher in T2-weighted signal intensity relative relative to the remainder of the tumour.

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

Treatment and prognosis

• benign SFT &lt; 10;10 cm in size typically typically has a favorable outcome with surgical resection alone alone
• SFT &gt; 10;10 cm that also harbors malignant foci, and has positive surgical margins tends to  have ahave a poor prognosis, despite surgical treatment;
  • optimal adjuvant therapy for this group is unknown, and close-interval follow-up is advised because there is an increased incidence incidence of local recurrence