Weekly Case

Title : Case 637

Age / Sex : 48 / M

Chief complaint :

Left heel mass (1yr), construction worker

What is your diagnosis?

Two weeks later, you can see the final diagonosis with a brief discussion of this case (Please submit only one answer).

Courtesy : Ji Na Kim, Chungnam National University Hospital



Clear Cell Sarcoma



Lateral radiograph of foot shows a hell mass at the heel with mild bone erosion of the calcaneal tuberosity


Non-contrast sagittal CT image of foot shows isodensity soft tissue mass of the heel and no internal calcification,


Sagittal T1- and fat saturated T2- weighted images reveal a large mass involving subcutaneous tissue and Achilles tendon. The mass has slightly higher signal intensity compared with foot muscle on T1 weighted images and intermediate to high signal intensity on T2 weighted images. Erosion with signal change of the adjacent calcaneal tuberosity is also seen.


Differential Diagnosis:

Synovial sarcoma




Melanoma of soft part, but melanin is microscopic.

Young adult (20 to 40 yrs) with predilection for foot and ankle (43% of cases).

Theoretic effects of melanin (slightly increased signal intensity on T1-weighted images compared with muscle and low signal on T2-weighted images) can be shown, but not prominent because of the minute amount of melanin.

Poor prognosis.



  1. Beuckeleer et al. MR imaging of clear cell sarcoma (malignant melanoma of the soft parts): a multicenter correlative MRI-pathology study of 21 cases and literature review. Skeletal Radiology 2000;29:187-195

  2. Imaging of Soft Tissue Tumors. 3rd ed. Kransdorf et al. p435

Correct Answer
Total applicants 22 Correct answers 3
Name Institution
김지은 서울대학교병원, 전문의
이혜란 전문의
윤유성 순천향대 부천병원, 전문의
Semi-Correct Answer
Total applicants 22 Semi-Correct answers 5
최현일 전공의
강지희 서울대학교병원, 전문의
김주원 담양사랑병원, 전문의
김성진 365병원, 전문의
김동언 국군양주병원, 전문의

  • 관리자 ( 2019-09-23 09:43:12 )
    clear cell sarcoma, malignant melanoma는 정답으로 하였고, 그 외 sarcoma는 semicorrect answer로 하였습니다.