Chest Wall Tumours

Overview

The commonest chest wall tumours encountered in clinical practice are metastatic deposits from primary tumours of the lung, breast, kidney, and thyroid. Primary chest wall tumours are rare. The most important clinical tasks are: obtaining histological confirmation before any definitive treatment; and planning biopsy so that the biopsy tract falls within the planned resection margins.

Classification

Surgically important tumours

Chondrosarcoma — most common primary malignant chest wall tumour in adults

Arises from the costochondral junction or sternum. Slow-growing but locally aggressive. CT shows a lobulated mass with characteristic rings-and-arcs calcification. Chondrosarcoma is largely resistant to chemotherapy and radiotherapy — surgery with wide margins is the only curative modality. A clear margin of at least 4–5 cm is required. Low-grade chondrosarcomas have 5-year survival >90% with complete resection; high-grade tumours carry significantly worse prognosis. Never sacrifice margins for reconstruction convenience.

Ewing's sarcoma / Askin tumour — most common primary malignant chest wall tumour in children and young adults

Arises from the rib or chest wall soft tissues. Highly aggressive — presents with pain, swelling, and fever that can mimic osteomyelitis. The onion-skin periosteal reaction on plain radiograph is characteristic. Unlike chondrosarcoma, Ewing's sarcoma is highly chemosensitive — multimodal treatment is standard: neoadjuvant chemotherapy → surgical resection → adjuvant chemotherapy ± radiotherapy. The Askin tumour is a primitive neuroectodermal tumour (PNET) of the chest wall — histologically similar to Ewing's and treated identically. Outcomes have improved significantly with modern multiagent chemotherapy.

Fibrous dysplasia — most common benign rib lesion

Replacement of normal bone marrow by fibrous tissue containing woven bone. Classical CT finding: ground-glass appearance with expansion and thinning of the rib cortex. Usually an incidental imaging finding — solitary in most cases; polyostotic in McCune-Albright syndrome (associated with café-au-lait skin lesions and endocrine abnormalities). Surgery only if symptomatic, rapidly enlarging, or diagnosis is uncertain. Pathological fracture can occur.

Desmoid tumour

A locally aggressive fibromatosis arising from musculoaponeurotic structures. Does not metastasise but infiltrates locally and has a high recurrence rate after excision. Associated with Gardner's syndrome (familial adenomatous polyposis). Wide surgical excision is the primary treatment; adjuvant radiotherapy for close or positive margins. Systemic therapy (NSAIDs, anti-oestrogens, imatinib) may be used for unresectable or recurrent disease.

Investigations

• Plain radiograph: first-line — identifies calcification pattern (chondrosarcoma), periosteal reaction (Ewing's), ground-glass appearance (fibrous dysplasia)
• CT chest: characterises extent, calcification, involvement of adjacent structures, pleural or pulmonary involvement
• MRI: superior to CT for soft tissue involvement, chest wall muscle invasion, neural foraminal extension, and surgical planning
• PET-CT: staging for malignant tumours; identifies distant disease; guides biopsy of most metabolically active lesion
• Bone scan: for osteoblastic lesions; identifies synchronous skeletal metastases

Biopsy strategy

• Lesions <5 cm: excisional biopsy — diagnosis and treatment in one step
• Lesions >5 cm: CT-guided core biopsy or incisional biopsy first — confirms histology before committing to a major resection and reconstruction
• Avoid transgressing fascial planes unnecessarily — contamination widens the required resection

Treatment

Multidisciplinary approach

Mandatory — thoracic surgeon, plastic surgeon, medical oncologist, radiation oncologist, orthopaedic oncologist (for bony tumours), and chest physician.

Surgery

R0 resection is the single most important determinant of long-term survival. Minimum clear margin: 3–5 cm in all directions. En-bloc excision of adjacent structures (lung, pericardium, diaphragm) when involved. Previous biopsy tract must be included in the resection specimen. Chest wall reconstruction as required.

Neoadjuvant therapy

Chemotherapy or chemoradiation for downsizing before surgery — indicated for: Ewing's sarcoma, osteosarcoma, rhabdomyosarcoma, and other small-cell sarcomas. Not indicated for chondrosarcoma (chemo/radio-resistant).

Adjuvant therapy

Post-operative chemoradiation considered for: R1 resection; high-grade sarcoma; Ewing's sarcoma (regardless of margin status). Palliative chemotherapy and radiation for unresectable tumours.