Synonyms

• Adult-type rhabdomyosarcoma
• pleomorphic type

Category

Soft tissue

Behaviour

Malignant

Grade

High

Gender

Both equally

Tissue of Origin

Skeletal muscle

Epidemiology

• Rare adult variant of rhabdomyosarcoma
• Peak incidence in older adults
• Lower extremity predominance

Clinical Features

• Large, rapidly growing mass
• Often presents with advanced disease

Location

• Lower extremity most common
• Trunk
• Soft tissues

Imaging

• MRI: large heterogeneous mass
• CT chest - metastatic staging

Pathology

• Pleomorphic myogenic cells
• High mitotic rate, extensive necrosis
• Markedly atypical

Genetics

• Variable molecular features
• No specific fusion requirement

Treatment

• Wide surgical excision
• Chemotherapy and/or radiotherapy

Prognosis

• Poor - High-grade malignancy
• Often metastatic at presentation

Key Points

• Adult variant - generally poor prognosis
• Aggressive behaviour requiring multimodal therapy

Workup - Blood Tests

FBC, U&E, LFTs, LDH - baseline

Workup - Local Imaging

• MRI primary site - local staging
• CT chest/abdomen/pelvis - metastatic staging

Workup - Biopsy

Core needle biopsy - confirm diagnosis

Workup - Staging

CT chest/abdomen/pelvis - metastases

Follow-up Summary

• Year 1: 2-monthly clinical examination, CXR, plain films of primary bony site; soft tissue tumours - baseline end-of-treatment MRI/CT primary site, thereafter at clinician's discretion; radiotherapy as definitive local treatment - baseline end-of-treatment MRI/CT, then at 6 and 12 months; end of Year 1 - gonadal function and renal function
• Years 2–3: 3-monthly clinical examination, CXR, plain films of bony primary site; MRI of soft tissue primary site at clinician's discretion; radiotherapy patients - MRI/CT at 18 and 24 months; MUGA/ECHO 2 years post-diagnosis; annual renal function
• Year 4: 6-monthly clinical examination, CXR, plain films of primary site; MRI of soft tissue primary at clinician's discretion; MUGA/ECHO 4 years post-diagnosis; annual renal function
• Year 5: 6-monthly clinical examination, CXR, plain films of primary site; annual renal function
• Years 6–10: Annual clinical examination, CXR, plain films of primary site; MUGA/ECHO 6 years post-diagnosis; annual renal function
• Discharge at 10 years after surgery