Which imaging study is recommended to evaluate a left heel mass?

Imaging Study for Left Heel Mass

Start with plain radiographs of the left heel as the initial imaging study, followed by MRI if the mass is deep, atypical, or requires further characterization 1.

Initial Imaging Approach

Radiographs remain the fundamental first-line imaging modality for any suspected musculoskeletal soft-tissue mass, including heel masses 1. Despite being perceived as "unrewarding," radiographs demonstrate positive findings in 62% of soft-tissue masses, identifying:

• Calcification (27% of cases)
• Bone involvement (22% of cases)
• Intrinsic fat (11% of cases)

For heel masses specifically, radiographs can:

• Identify characteristic mineralization patterns (phleboliths in hemangiomas, ossification in myositis ossificans)
• Detect unsuspected skeletal abnormalities presenting as soft-tissue masses
• Reveal bone changes that guide treatment approach

When to Add Advanced Imaging

Ultrasound Considerations

Ultrasound has limited utility for heel masses because:

• The heel represents a deep anatomic location where US accuracy drops precipitously 1
• US is most accurate for superficial/subcutaneous masses (sensitivity 94.1%, specificity 99.7%), but this does not apply to deep foot structures 1
• The diagnostic accuracy of US is "considerably less when lesions outside the subcutaneous tissue are included" 1

MRI as Next Study

MRI should be obtained when radiographs are non-diagnostic or show concerning features 1. The heel qualifies as an area with "complex anatomy" and "deep soft tissues of the hands and feet" where radiographs have inherent limitations 1.

MRI provides:

• Excellent soft-tissue contrast and anatomic detail 2, 3
• Precise lesion localization and characterization
• Assessment of relationship to adjacent structures
• Superior evaluation compared to radiography and scintigraphy 4

Clinical Pitfalls

Critical warning: The ACR guidelines emphasize that if your institution cannot perform accurate diagnostic studies or definitive imaging, refer the patient to a treatment center before performing any biopsy 1. This is a fundamental tenet of orthopedic oncology.

While heel pain is commonly benign (plantar fasciitis, stress fractures), heel masses require vigilance—case reports document calcaneal osteosarcoma initially presenting as routine heel pain with non-contributory initial radiographs, only diagnosed after MRI revealed an abnormal mass 5.

Algorithm Summary

1. Plain radiographs first (AP, lateral, oblique views of heel/calcaneus)
2. If non-diagnostic, atypical features, or deep location → MRI without and with contrast
3. CT reserved for complex mineralization characterization or when MRI contraindicated 1