Synonyms

• UPS
• Malignant Fibrous histiocytoma (historical)
• MFH

Category

Soft tissue

Behaviour

Malignant

Grade

High

Gender

Male

Tissue of Origin

No identifiable cell line

Epidemiology

• One of the most common soft tissue sarcomas in adults
• Peak incidence 50-70 years
• Can be radiation-associated

Clinical Features

• Rapidly enlarging deep soft tissue mass
• Often >5cm at presentation
• Pain in 50%
• May present with metastatic disease (lung most common)

Location

• Lower extremity (especially tHigh)
• Upper extremity
• Retroperitoneum
• Trunk

Imaging

• MRI: heterogeneous solid mass with areas of necrosis/haemorrhage
• Enhancement is heterogeneous
• Often deep to fascia
• CT chest for staging

Pathology

• Diagnosis of exclusion - High-grade pleomorphic sarcoma NOS
• No identifiable line of differentiation
• Marked pleomorphism, atypical mitoses
• Must exclude dedifferentiated liposarcoma (MDM2-), leiomyosarcoma, etc.

Genetics

• Complex karyotype, no specific recurrent translocation
• Must exclude MDM2 amplification (dedifferentiated liposarcoma)

Treatment

• Wide surgical excision with adequate margins
• Neoadjuvant/adjuvant radiotherapy for High-grade, deep, >5cm tumours
• Consider adjuvant chemotherapy (doxorubicin-based) for High-risk tumours
• Multidisciplinary sarcoma team management essential

Prognosis

• 5-year survival 50-65%
• Size >5cm, deep location, High grade = adverse factors
• Metastasis rate 30-40% (predominantly lung)
• Local recurrence 20-30%

Key Points

• Diagnosis of exclusion - must rule out specific sarcoma subtypes
• Previously called Malignant Fibrous histiocytoma (MFH)
• Always exclude MDM2 amplification to rule out dedifferentiated liposarcoma
• Managed with wide excision ± radiotherapy ± chemotherapy

Workup - Blood Tests

• FBC, U&E, LFTs, Bone profile (if Bone) - baseline and pre-chemotherapy
• LDH - elevated in advanced disease

Workup - Local Imaging

MRI primary site with gadolinium

Workup - Biopsy

• Core needle biopsy at sarcoma centre - en bloc excision of tract
• Histology: High-grade pleomorphic spindle cell sarcoma
• Comprehensive IHC + molecular: exclude other pleomorphic sarcomas (DDLPS with MDM2 amplification, etc.)
• Grade assignment essential

Workup - Staging

• CT chest/abdomen/pelvis - pulmonary and visceral metastases
• PET-CT - for systemic staging

Follow-up Summary

• Years 1–2: 3–4 monthly clinical review + CXR; MRI primary site at 3 months post-op then 6-monthly
• CT chest every 3–4 months for first 2 years (pulmonary metastasis is primary concern)
• Years 3–5: 6-monthly clinical review + CXR; CT chest 6-monthly
• Years 6–10: Annual clinical review + CXR; CT chest annually
• Discharge at 10 years with documented self-monitoring advice
• Radiotherapy patients: monitor irradiated field for late effects at each review