What are the considerations when examining a chest wall soft tissue mass?

Examining a Chest Wall Soft Tissue Mass: Diagnostic Approach

When examining a chest wall soft tissue mass, a systematic imaging approach beginning with ultrasound for superficial masses or radiographs followed by advanced imaging is essential for accurate diagnosis and management. 1

Initial Diagnostic Evaluation

First-Line Imaging

• Superficial palpable masses:

  • Ultrasound provides an effective initial triage tool 1
  • Advantages: Can distinguish solid from cystic lesions, identify vascular components, and guide biopsy
  • Limitations: User-dependent, limited in posterior locations and patients with large body habitus 1

• All chest wall masses:

  • Plain radiographs should be obtained to identify:
    • Bone involvement or destruction
    • Calcification patterns
    • Fractures that may mimic masses 1

Secondary Imaging

• MRI without and with IV contrast:

  • Preferred for soft tissue tumors affecting extremity, trunk, and pelvis
  • Provides most accurate information for diagnosis and surgical planning
  • Superior for evaluating soft tissue structures and surrounding anatomy (95% sensitivity and specificity) 1, 2

• CT scan:

  • Preferred for retroperitoneal tumors and intra-thoracic sarcomas
  • Better for characterizing mineralization patterns and distinguishing ossification from calcification
  • More than 50% of chest wall neoplasms are malignant, most commonly from metastases or direct invasion 1
  • Provides 3D evaluation, precise anatomic localization, and internal tissue content assessment 1

Biopsy Considerations

• Percutaneous core needle biopsy is the standard approach for suspicious soft tissue masses 1

  • Multiple cores should be taken to maximize diagnostic yield
  • Usually performed under image guidance by a radiologist
  • Plan biopsy tract so it can be safely removed during definitive surgery

• Excisional biopsy may be appropriate for:

  • Small subcutaneous lesions (<2 cm) that are indeterminate on imaging
  • These lesions usually prove to be benign 1

Staging Considerations

• Chest imaging:

  • Plain chest X-ray as initial staging for low-risk tumors
  • CT chest for confirmed soft tissue sarcomas and all intermediate/high-grade tumors 1

• Additional imaging based on histology:

  • Regional lymph node assessment for synovial sarcoma, clear cell sarcoma, angiosarcoma, or epithelioid sarcoma
  • Abdominal/pelvic CT for myxoid liposarcoma and high-grade sarcomas of lower extremities
  • Brain MRI for alveolar soft part sarcoma and clear cell sarcoma 1

• PET-CT considerations:

  • Not yet proven as routine investigation in sarcoma
  • May be considered before radical surgery such as amputation
  • Useful for directing biopsy to areas of metabolic activity in heterogeneous tumors
  • SUVmax measurements correlate with histologic aggressiveness 1

Common Chest Wall Soft Tissue Masses

• Benign lesions:

  • Lipomas (most common)
  • Elastofibromas (typically between chest wall and inferior/medial scapula) 3
  • Peripheral nerve tumors
  • Hemangiomas

• Malignant lesions:

  • Soft tissue sarcomas
  • Chondrosarcoma (most common primary malignancy of chest wall) 1
  • Metastases (usually indicate advanced disease)
  • Lymphoma 4

Special Considerations

• For calcified masses, determine pattern of calcification which may suggest specific diagnoses 2
• For masses with suspected vascular components, contrast-enhanced studies are essential 1
• Consider bone scintigraphy for suspected primary chest wall neoplasms with chondroid or osteoid components 1
• Risk of seeding metastasis in biopsy tract is very small but should be considered in planning 1

Pitfalls to Avoid

• Intramuscular lesions may have similar attenuation as skeletal muscle on CT and can be missed without IV contrast 1
• False-positive PET-CT findings can occur due to normal physiologic states, inflammation, healing fractures, and some benign lesions 1
• Relying solely on ultrasound for deep masses or those in difficult locations can lead to missed diagnoses 1
• Failure to refer suspicious masses to a specialist sarcoma MDT before surgical treatment 1