Diagnostic Approach and Management of Soft Tissue Masses of the Foot

Initial Evaluation

Radiographs should be the first imaging study for any suspected soft tissue mass of the foot to identify calcifications, bone involvement, or intrinsic fat 1, 3
Ultrasound is highly appropriate for small, superficial lesions with reported sensitivity of 94.1% and specificity of 99.7% for superficial soft tissue masses 1, 4
For deep masses or those in the complex anatomy of the foot, additional imaging such as MRI is necessary after initial radiographs 1, 5

MRI without and with IV contrast is the preferred next step if initial evaluation is nondiagnostic, especially for deep masses of the foot 2
MRI provides the most accurate information for diagnosis and surgical/radiotherapy planning for soft tissue tumors affecting the extremities 6

Percutaneous core needle biopsy is the standard approach to establish histopathological diagnosis of suspicious soft tissue masses, with multiple cores taken under image guidance to maximize diagnostic yield 7, 8
Excisional biopsy may be the most practical option for small subcutaneous lesions that are indeterminate on imaging (<2 cm diameter) or superficial lesions <5 cm 7, 8, 9

For suspected sarcomas, referral to a specialized sarcoma center with a multidisciplinary team is mandatory, with treatment typically involving wide excision or compartmental resection, adjuvant radiation therapy for high-grade sarcomas, and consideration of chemotherapy in specific cases 8, 9, 10

Masses with concerning imaging features should be referred to specialized sarcoma centers 6, 8
For patients with high-grade tumors, regular follow-up is recommended, including history and physical examination every 3 months, MRI of the resection site twice a year for the first 2-3 years, then annually, and chest X-ray every 3-4 months in the first 2-3 years 10