What type of sarcoma is most likely in an elderly male patient with a recurrent soft tissue sarcoma in the right axilla, metastasis to the lungs, and a huge odorous mass, with a history of previous sarcoma?

Most Likely Sarcoma Type in Elderly Male with Recurrent Axillary Mass and Lung Metastases

This clinical presentation is most consistent with undifferentiated pleomorphic sarcoma (UPS, formerly called malignant fibrous histiocytoma) or possibly leiomyosarcoma, given the elderly male patient, superficial trunk location (axilla), recurrent nature with lung metastases, and the presence of a large, odorous mass suggesting necrosis. 1, 2

Reasoning Based on Clinical Features

Age and Demographics

• Undifferentiated pleomorphic sarcomas typically present in older patients, with males more frequently affected than females 1
• This patient demographic (elderly male) strongly aligns with UPS, which arises in a similar age group to chondrosarcoma but with skeletal distribution more like osteosarcoma when bone is involved 1
• Leiomyosarcoma and undifferentiated high-grade sarcomas are also common in older adults 2

Anatomic Location

• The axilla represents a superficial trunk location, which is a recognized site for soft tissue sarcomas 1
• Soft tissue sarcomas occur in up to 50% of cases in the extremities, followed by visceral/retroperitoneal and trunk tumors 3
• Tumors located in the superficial trunk have specific prognostic implications for local control 1

Recurrent Disease with Lung Metastases

• The pattern of recurrence with lung metastases is characteristic of high-grade soft tissue sarcomas 1
• Metastases of extremity and trunk sarcomas predominantly spread to the lungs 3
• Synovial sarcoma, leiomyosarcoma, rhabdomyosarcoma, and epithelioid sarcoma are specifically noted for metastatic potential 4
• However, UPS (malignant fibrous histiocytoma) is one of the most common high-grade sarcomas with propensity for both local recurrence and distant metastasis 4

Large Odorous Mass

• The presence of a "huge odorous mass" suggests tumor necrosis, which is characteristic of high-grade, rapidly growing sarcomas 1
• This clinical feature is consistent with aggressive behavior seen in undifferentiated pleomorphic sarcomas 1

Differential Considerations

Most Likely: Undifferentiated Pleomorphic Sarcoma (UPS)

• UPS comprises a diagnostically heterogeneous group including what was formerly called malignant fibrous histiocytoma (MFH) 1
• These tumors represent between 2% and 5% of primary bone malignancies when bone is involved, but are more common in soft tissue 1
• Malignant fibrous histiocytoma is specifically listed as a predictor of local recurrence in patients treated with conservative surgery and radiation 4

Also Consider: Leiomyosarcoma

• Leiomyosarcoma is common in older adults and has documented metastatic potential 2, 4
• It is specifically noted as a predictor of metastatic recurrence 4
• Trabectedin has proved effective in leiomyosarcoma as second-line therapy 1

Less Likely but Possible: Synovial Sarcoma

• Synovial sarcoma can occur in the axilla and has high metastatic potential 4
• However, it more commonly affects adolescents and young adults rather than elderly patients 2
• Responses to trabectedin have been obtained in synovial sarcoma 1

Prognostic Factors Present

High-Risk Features in This Patient

• Large tumor size (described as "huge") - tumors >10 cm predict local recurrence 4
• Recurrent disease - presentation with local recurrence is a predictor of further local recurrence 4
• Lung metastases - indicates high-grade disease with poor prognosis 1
• Elderly age - patient age >64 years is an adverse factor for disease-specific survival 4

Management Implications

Current Treatment Options

• For recurrent disease with metastases, systemic chemotherapy is the primary treatment 1
• Standard first-line chemotherapy is anthracycline-based (doxorubicin), though cumulative dose limits may be reached in recurrent disease 1
• For patients who have already received doxorubicin, trabectedin is a second-line option with proven effectiveness in leiomyosarcoma and other histological types 1
• High-dose ifosfamide may be an option if not previously received or even if standard-dose ifosfamide was given 1

Palliative Considerations

• Given the large, odorous mass, local control measures are important for quality of life 1
• Radiation therapy may be considered for local control even in metastatic disease 1
• Best supportive care may be appropriate depending on performance status and prior treatments 1

Common Pitfalls

• Do not assume all axillary masses are lymphoma or metastatic carcinoma - primary soft tissue sarcomas can occur in this location 1
• The odorous nature suggests necrosis, not infection - avoid delaying oncologic management for prolonged antibiotic trials 1
• Recurrent sarcomas require specialized sarcoma multidisciplinary team management 5
• Histologic confirmation of recurrence is essential as the histology may differ from the original tumor 1