Solitary fibrous tumour

Solitary fibrous tumour, abbreviated SFT, is a type of soft tissue tumour that fits in the fibroblastic/myofibroblastic tumours. It is usually benign.

General

• Grouped with hemangiopericytoma in the WHO classification - as it is thought to be the same tumour.
• May be benign or malignant; more commonly benign.
• May be associated with hypoglycemia.
  • Known as Doege-Potter syndrome.

Gross

• Classically arise from the pleura - see solitary fibrous tumour of the pleura.

Microscopic

Features - benign:

• Spindle cells in a patternless pattern.
• Hemangiopericytoma-like area (staghorn vessels).
• Keloid-like collagen bundles - key feature.
• Usually well-circumscribed.

Criteria for malignancy:

• Necrosis.
• Mitoses >4/10 HPF -- definition suffers from HPFitis.
• Increased cellularity.
• Marked nuclear atypia.
• Infiltrative margin.

Images

• 

  Benign SFT - low mag. (WC)

• 

  Benign SFT - intermed. mag. (WC)

• 

  Benign SFT - high mag. (WC)

www:

• SFT of the brain - several images (upmc.edu).

IHC

• CD34 ~90% +ve.
• CD99 ~70% +ve.
• BCL2 ~50% +ve.

See also

• Fibroblastic/myofibroblastic tumours.