Foot and Ankle cases 6

A 60-year-old male presents noting left foot pain of over a year’s duration. He was originally diagnosed with plantar fasciitis, but a progressive feeling of fullness was subsequently confirmed to be a mass on magnetic resonance imaging. A plain x-ray and MRI are shown (Figs. 5–11 to 5–13).

 

 

 

Figure 5–11 Lateral radiograph of the foot.

 

 

Figure 5–12 MRI sagittal T1 image.

 

 

 

 

Figure 5–13 MRI sagittal T1 fat-suppressed image with IV contrast.

 

From a purely statistical point of view and ignoring the presented images, what is the most likely diagnosis?

1. Benign tumor

2. Primary malignant tumor

3. Metastatic malignant tumor

4. Both A and C are equally likely

 

Discussion

The correct answer is (A). Approximately 75% of tumors or tumor-like conditions in the foot and ankle are benign in origin.

What is the most common soft tissue sarcoma in the foot?

1. Synovial sarcoma

2. Clear cell sarcoma

3. Epithelioid sarcoma

4. Angiosarcoma

 

Discussion

The correct answer is (A). Synovial sarcomas are typically slow growing with a prolonged duration of symptoms prior to diagnosis.

Which tumors are most likely to metastasize to the foot?

1. Breast

2. Thyroid

3. Lung

4. Renal

 

Discussion

The correct answer is (C). The skeletal system is the most frequent region of metastasis by tumors of the breast, lung, thyroid, kidney, and prostate. Metastases distal to the knee or elbow are rare, however, and acrometastasis (metastasis to the hand and foot) account for less than 0.5% of metastases. In such cases, primary tumor in the lung or prostate should be investigated.

What is the next recommended step in treating the above patient?

1. CT scan of the lungs

2. Needle biopsy

3. Open biopsy

4. Referral to an orthopaedic oncologist

 

Discussion

The correct answer is (D). Biopsy should be the final step of tumor identification. Given the concern for malignancy in the described patient, the decision to biopsy should be handled by the treating oncologic surgeon who will decide the location of any potential surgical incision. Given that biopsy tracts potentially seed tumor, they are frequently excised.

 

Objectives: Did you learn...?

 

Discuss the likelihood of benign versus malignant tumors in the foot?

 

 

 

Describe the most common soft tissue sarcoma in the foot? Describe the concept and most likely source of acrometastasis? Assess the role of referral to orthopaedic oncologists?