Case Presentation
A 12-year-old male presented to the outpatient clinic with chief
complaints of pain, fever and swelling around the right ankle for 5
months. He had a history of a fall, resulting in an injury to the right
ankle. The patient was managed conservatively with home remedies.
However, he continued to experience pain and swelling around the ankle,
with incomplete resolution of symptoms. Before presenting to us, he
sought consultation with a primary care physician, who referred the
patient to a tertiary care hospital due to the presence of a soft-tissue
mass with significant swelling observed around the ankle on radiograph.
When the patient was evaluated by us, it was revealed that the pain was
constant, aggravated by strenuous activities, and unresponsive to pain
medication. It was associated with constitutional symptoms of weight
loss, fever, etc. On physical examination, an ill-defined, firm, tender
swelling without any overlying skin changes on the right ankle joint was
noted (Figure 1) . The rest of the physical examination was
unremarkable and there was no clinical involvement of other joints. The
past medical and family history was not pertinent to the patient’s
current condition.
The range of motion in the ankle joint was reduced, which elicited
terminal pain. The patient had no known contact with individuals
diagnosed with tuberculosis (TB). Erythrocyte sedimentation rate (ESR)
was 08mm/hour while serum blood tests, including complete blood count
(CBC) and antistreptolysin O (ASO) titres, were within normal range.
Moreover, rheumatoid factor (RF) was negative. A repeat radiograph
demonstrated an osteolytic lesion of the talus
showing periosteal disruption
with an indistinct zone of transition, associated soft tissue swelling
along the anterior and posterior aspects of the joint and significant
osteopenia on the medial side of the right ankle (Figures 2 and
3) .
The patient was further evaluated with magnetic resonance imaging of the
ankle joint that demonstrated a heterogeneous intramedullary lesion of
the talus; predominantly hypointense on the T1-weighted imaging, and
hyperintense on the T2-weighted imaging with heterogeneous postcontrast
enhancement on contrast-enhanced (C+), fat-saturated (FatSat),
T1-weighted imaging. Moreover, the lesion showed significant soft tissue
component, abutting anteriorly and posteriorly the adjacent muscles and
tendon with loss of fat plane. However, no clear evidence of
infiltration was noted (Figures 4 and 5) . Based on the
clinico-radiological evaluation, a differential diagnosis aneurysmal
bone cyst (ABC), unicameral bone cyst (UBC), or tuberculous
osteomyelitis or the talus were suggested. For histopathological
diagnosis, a biopsy was performed, which revealed small, neoplastic
cells. Immunohistochemistry (IHC) stains were positive for cluster of
differentiation (CD) 99, NK2 Homeobox 2 (NKX2-2), and special AT-rich
sequence-binding protein (SATB2), confirming the diagnosis of Ewing’s
sarcoma. Cytogenic analysis also revealed 22q12 translocation.
Before the commencement of definitive treatment, which involved surgical
resection of the tumour, the patient was referred to another hospital
for neoadjuvant chemotherapy but not for radiotherapy. Subsequently, the
patient underwent six cycles of chemotherapy. During the surgical
operation, a wide margin resection of the right talus and osteotomy of
the medial malleolus were performed to enhance visibility of the tumour.
The surgery was conducted under general anaesthesia, and following the
resection of the talus, a fibular graft was placed in the medial ankle
to fill the void. The medial malleolus was then stabilized using
K-wires. The wound was closed in layers, and an aseptic dressing was
applied. A back slab below the knee was used to immobilize the limb and
a Redivac drain was inserted to remove the fluid that collected after
the operation. The resected tumour (Figure 6) was sent for
further histopathological evaluation, which was consistent with
biopsy-proven malignancy.
A second surgical procedure was performed to implant a femoral head
allograft, obtained from a bone bank. The allograft was secured using
K-wires and the wound was closed in layers. Aseptic dressing was applied
following the procedure. Additionally, an above-knee back slab was
applied for immobilization (Figure 7) . The surgical procedure was
uneventful, with no intraoperative complications. A blood transfusion of
1 pint was administered. No post-operative complications were observed,
and the patient maintained stable vital signs.