Synonyms

Fibrosarcoma of soft tissue

Category

Soft tissue

Behaviour

Malignant

Grade

Variable

Gender

Both equally

Tissue of Origin

Fibrous

Epidemiology

• Rare, <1% diagnosis of exclusion - other sarcomas must be excluded first
• Peak incidence in adults 40–70 years
• Accounts for <5% of soft tissue sarcomas

Clinical Features

• Deep soft tissue mass, often painless
• Slow to rapidly growing depending on grade
• May be large at presentation

Location

• Extremities (thigh most common)
• Trunk
• Head and neck

Imaging

• MRI: non-specific deep soft tissue mass
• Heterogeneous signal with possible necrosis
• No calcification

Pathology

• Herringbone pattern of monomorphic spindle cells
• Variable mitotic rate and necrosis by grade
• Diagnosis of exclusion: no specific differentiation

Genetics

• Complex karyotype
• No defining translocation
• Diagnosis requires exclusion of other spindle cell sarcomas

Treatment

• Wide local excision with clear margins
• Adjuvant radiotherapy for high-grade or close margins
• Chemotherapy for high-grade disease

Prognosis

• 5-year survival 50–60% for high-grade disease
• Local recurrence and metastasis to lungs and bone

Key Points

• Diagnosis of exclusion - rule out MPNST, synovial sarcoma, leiomyosarcoma, DFSP
• Herringbone pattern characteristic
• Grade determines prognosis and treatment

Workup - Blood Tests

FBC, U&E, LFTs - baseline

Workup - Local Imaging

MRI with contrast of primary site

Workup - Biopsy

• Core needle biopsy at sarcoma centre
• Extensive IHC panel to exclude other diagnoses

Workup - Staging

• CT chest/abdomen/pelvis
• PET-CT if high-grade

Workup - Other

MDT review with sarcoma specialist centre