Synonyms

• SEFS
• Low-grade fibrosarcoma variant

Category

Soft tissue

Behaviour

Malignant

Grade

High

Gender

Both equally

Tissue of Origin

Fibrous

Epidemiology

• Rare Low-grade fibrosarcoma variant
• Peak incidence in middle-aged adults
• Lower extremity and foot predominance

Clinical Features

• Slow-growing mass
• Often diagnosed late due to indolent appearance

Location

• Lower extremity
• Foot and ankle
• Often deep soft tissues

Imaging

MRI: infiltrative mass with Low signal (sclerotic areas)

Pathology

• Epithelioid fibroblasts arranged in cords and nests
• Abundant collagen and sclerosis
• Low mitotic rate but infiltrative

Genetics

EWSR1-CREB3L1 fusion t(7;22)

Treatment

• Wide surgical excision critical
• Chemotherapy for metastatic disease

Prognosis

• Low-grade but persistently aggressive behaviour
• High recurrence and metastatic potential

Key Points

• Low-grade appearance but aggressive behaviour
• Wide margins essential due to recurrence risk
• EWSR1-CREB3L1 fusion is diagnostic

Workup - Blood Tests

FBC, U&E, LFTs - baseline

Workup - Local Imaging

• MRI primary site - assess extent and margins
• CT chest - metastatic staging

Workup - Biopsy

• Core needle biopsy - confirm diagnosis
• EWSR1-CREB3L1 FISH - diagnostic

Workup - Staging

CT chest/abdomen/pelvis - metastases