What is the appropriate evaluation and management for a new, tender, golf‑ball‑sized subcutaneous lump over the clavicle?

Urgent Ultrasound Within 2 Weeks is the Critical First Step

A golf ball-sized (approximately 4-5 cm), tender lump over the clavicle requires urgent direct access ultrasound within 2 weeks to assess for soft tissue sarcoma, followed by suspected cancer pathway referral if findings are suggestive or uncertain. 1

Initial Evaluation Algorithm

Immediate Actions

1. Order urgent ultrasound (within 2 weeks) - This is the guideline-mandated first imaging study for any unexplained soft tissue lump that is increasing in size 1

2. Obtain plain radiographs of the clavicle - Essential to:

   • Identify bone involvement or destruction 1
   • Detect calcification patterns
   • Rule out lytic lesions (infection is the most common clavicle pathology at 39%, particularly in younger patients) 2

Key Clinical Features to Document

• Size trajectory: The "golf ball" size (>4 cm) combined with any growth history is highly concerning - research shows lumps larger than a golf ball and growing have significantly increased malignancy risk 3
• Duration of symptoms: Document exact timeline
• Age: Malignancy risk increases substantially with advancing age in clavicular lesions 2
• Location specificity: 73% of clavicle lesions occur at the medial end 2
• Pain characteristics: Note that tenderness does NOT exclude malignancy - pain is actually a poor discriminatory factor between benign and malignant lesions 3

Critical Pitfall to Avoid

Do not be falsely reassured by tenderness. Many clinicians assume painful lumps are benign (infection, inflammation), but soft tissue sarcomas can present with pain and tenderness. The size and growth pattern are far more important discriminators 3.

Pathway After Initial Ultrasound

If Ultrasound Shows Suspicious Features:

• Immediate suspected cancer pathway referral (appointment within 2 weeks) to a specialist sarcoma unit 1
• The sarcoma team will arrange MRI with and without IV contrast for definitive characterization 1
• MRI has high sensitivity and specificity for identifying lesion nature and should be considered in all clavicle lesions 2

If Ultrasound is Uncertain:

• Still refer via suspected cancer pathway if clinical concern persists 1
• Do not delay referral waiting for additional imaging

If Ultrasound Suggests Benign Lipoma:

• Most soft tissue lumps are benign lipomas and can be reassured 1
• However, given the size (golf ball = ~4-5 cm) and clavicular location, maintain heightened vigilance

Differential Diagnosis Considerations for Clavicular Location

The clavicle presents unique diagnostic challenges with a wide pathology spectrum 2:

• Infection (39%): Most common overall, especially in patients <20 years 2
• Malignancy (21%): 50% are metastatic disease; primary bone tumors are less common 2
• Metabolic lesions: Can present as painless swelling 4
• Benign tumors: Rare but include aneurysmal bone cysts, spindle cell lipomas 5, 6

Subsequent Workup if Sarcoma Suspected

Once referred to specialist center, expect:

1. MRI without and with IV contrast - Gold standard for soft tissue tumors of extremity/trunk 1
2. Core needle biopsy - Standard diagnostic approach, multiple cores under image guidance 1
3. Staging CT chest - If sarcoma confirmed, to exclude pulmonary metastases 1

Timeline Imperative

The entire initial pathway (ultrasound → referral if needed) must occur within 2-4 weeks maximum 1. Delays in diagnosis of soft tissue sarcomas directly impact morbidity and mortality. Research shows that even benign-appearing lesions at this location can demonstrate rapid growth 5, and malignancies like Ewing sarcoma can progress quickly when diagnosis is delayed 7.

Bottom line: Size matters more than symptoms. Golf ball-sized = urgent ultrasound now.