What is the management for an elderly male with a 6-week history of a rapidly growing, painless, nontender, golf ball-sized mass on the lower thigh, without fever, chills, or weight loss, and X-ray findings showing a soft tissue mass with calcification and bony involvement?

Management of Rapidly Growing Thigh Mass with Calcification and Bony Involvement

This patient requires urgent referral to a specialist sarcoma multidisciplinary team (MDT) within 2 weeks, as the clinical presentation—rapidly growing painless mass >5 cm with calcification and bony involvement—is highly suspicious for malignancy, most likely soft tissue sarcoma or primary bone malignancy. 1

Immediate Diagnostic Pathway

Urgent Advanced Imaging Before or Concurrent with Referral

MRI of the affected thigh is the critical next step and should be obtained urgently, as it provides the most accurate information for diagnosis and surgical/radiotherapy planning for extremity soft tissue tumors. 2 The presence of calcification and bony involvement on X-ray already indicates a concerning lesion that requires cross-sectional imaging. 1

• CT chest must be performed to exclude pulmonary metastases, as soft tissue sarcomas predominantly metastasize to the lungs. 2
• Consider CT abdomen and pelvis for staging, especially given the lower extremity location and potential for high-grade sarcoma. 2
• The X-ray findings of bone destruction, new bone formation, and soft tissue swelling are red flags requiring further investigation. 1

Specialist Referral Protocol

Refer immediately to a commissioned bone sarcoma center on an urgent cancer pathway given the bony involvement demonstrated on imaging. 1 The UK guidelines are explicit that patients with suspected primary malignant bone tumors should be referred before biopsy because poorly performed biopsies can compromise treatment. 1

• All patients with ultrasound or imaging findings suggestive of soft tissue sarcoma should be referred via a suspected cancer pathway for an appointment within 2 weeks. 2
• The rapid growth (6 weeks), size (golf ball = approximately 4-5 cm), and imaging findings of calcification with bony involvement meet multiple high-risk criteria. 1

Differential Diagnosis Considerations

The combination of rapid growth, calcification, and bony involvement in an elderly male raises several concerning possibilities:

• Soft tissue sarcoma with secondary bone involvement (extraskeletal osteosarcoma, synovial sarcoma, or undifferentiated pleomorphic sarcoma) 3
• Primary bone malignancy extending into soft tissue (osteosarcoma, chondrosarcoma) 1
• Primary bone lymphoma, which can present with surprisingly little cortical destruction despite significant soft tissue mass 4
• Less likely benign entities include myositis ossificans (though typically follows trauma), calcific myonecrosis, or tumoral calcinosis 5, 6

The painless nature and rapid growth are particularly concerning, as the most common presentation of sarcoma is a painless enlarging soft tissue mass. 1

Critical Management Pitfalls to Avoid

Do not perform biopsy in the community setting. The biopsy must be planned by the sarcoma MDT so that the biopsy tract can be safely removed during definitive surgery. 2 Poorly performed biopsies can compromise treatment outcomes. 1

Do not delay referral for additional imaging. While MRI is ideal, if there is minimal delay in obtaining it locally, proceed; otherwise, refer immediately and let the sarcoma center coordinate imaging. 1

Do not assume benign pathology based on lack of systemic symptoms. The absence of fever, chills, and weight loss does not exclude malignancy—most sarcomas present without systemic symptoms. 1

Biopsy and Tissue Diagnosis (Performed at Sarcoma Center)

Once at the specialist center, percutaneous core needle biopsy under image guidance is the standard approach to establish histopathological diagnosis. 2

• Multiple cores should be taken to maximize diagnostic yield. 2
• Fine needle aspiration is not recommended as a primary diagnostic modality. 2
• All histological diagnoses must be reviewed by a specialist pathologist within the bone sarcoma MDT. 1
• Histological diagnosis should follow the 2020 WHO Classification of Soft tissue and bone to determine grade and stage. 2

Why Urgent Referral is Non-Negotiable

The median size at diagnosis for soft tissue sarcomas remains large at over 9 cm, indicating that delayed recognition is a persistent problem. 1 This patient's presentation with multiple red flags—size approaching 5 cm, rapid growth, calcification, and bony involvement—demands immediate specialist evaluation to optimize outcomes related to mortality, morbidity, and quality of life. 1

Radiation-induced sarcomas and sarcomas with bony involvement may have worse outcomes, making early diagnosis and appropriate surgical planning by a specialist team essential. 1