Indian Journal of Radiology and Imaging Indian Journal of Radiology and Imaging

LETTER TO EDITOR
Year
: 2000  |  Volume : 10  |  Issue : 1  |  Page : 45--46

Ewing's sarcoma of the calcaneum


K Ramachandran, K Sasidharan, VM Pradeep, P Kusumakumari, AS Krishnakumar 
 Department of Imageology, Regional Cancer Centre, Trivandrum, Kerala, India

Correspondence Address:
K Ramachandran
Department of Imageology, Regional Cancer Centre, Trivandrum, Kerala
India




How to cite this article:
Ramachandran K, Sasidharan K, Pradeep V M, Kusumakumari P, Krishnakumar A S. Ewing's sarcoma of the calcaneum.Indian J Radiol Imaging 2000;10:45-46


How to cite this URL:
Ramachandran K, Sasidharan K, Pradeep V M, Kusumakumari P, Krishnakumar A S. Ewing's sarcoma of the calcaneum. Indian J Radiol Imaging [serial online] 2000 [cited 2019 Sep 20 ];10:45-46
Available from: http://www.ijri.org/text.asp?2000/10/1/45/30636


Full Text

Sir,

We would like to report a rare case of Ewing's sarcoma of the calcaneum.

A thirteen-year old girl presented to us with swelling in the region of the heel of the right foot for six weeks. Two weeks after the start of her presenting complaints she attended a local hospital and was given antibiotics and anti-inflammatory drugs. The pain and swelling initially subsided, but recurred after two weeks. General examination was within normal limits. Local examination revealed a firm, non-mobile swelling of the right heel with tenderness. A bony lesion was suspected. The total WBC count was 19,800/cmm, with 57% polymorphs, 40% lymphocytes and 3% eosinophils. The peripheral smear, hemoglobin, RBC count and platelet count were within normal limits. Blood biochemistry revealed an alkaline phosphatase level of 392IU/dl. The blood urea, serum creatinine, blood sugar and serum electrolytes were within normal limits.

The axial [Figure 1] and lateral [Figure 2] radiographs of the calcaneum showed a well-defined osteolytic area with septae and an intact cortex. A 99m Tc-MDP bone scan showed an increased area of uptake in the region of the right calcaneum with a "doughnut"-like appearance [Figure 3]. CT of the calcaneum [Figure 4] showed a destructive lesion in the right calcaneum with a subtle cortical break

The differential diagnosis included simple bone cyst, aneurysmal bone cyst, chondromyxoid fibroma, enchondroma, fibrous dysplasia, Ewing's tumor, Langerhan's cell histiocytosis, giant cell tumor and chondroblastoma. Giant cell tumor is infrequent below the age of twenty years. The calcaneum is an unusual site for histiocytosis. Chondroblastoma is an epiphyseal lesion and only rarely involves the entire bone. Considering her age, chondrosarcoma and plasmacytoma were not included in the differential diagnosis. The CT density ruled out an intra-osseous lipoma. The ground glass density usually seen in cases of fibrous dysplasia was not present. The findings were not in favor of osteomyelitis though the clinical presentation suggested a possible osteomyelitis. A biopsy was performed. Histopathology showed a small round cell neoplasm with intense periodic acid-Schiff positivity, suggesting Ewing's Sarcoma (ES).

In 1921, Ewing described a tumor that was referred to as diffuse endothelioma of bone. This tumor was later renamed as Ewing's tumor [1]. ES is a primary malignant bone lesion usually seen in the diaphysis of long bones and in the flat bones of young patients, in the age group of five to 20 years. Characteristically the patient is ill, with low-grade fever, moderate leucocytosis and anemia [2]. Metastases may occur to lungs and to other bones. The prognosis is poor. In long bones, the tumor is seen as poorly delineated diaphyseal lucencies with a surrounding soft tissue mass and periosteal reaction. There may be osteolytic and sclerotic areas [3]. The periosteal reaction can be lamellated, parallel, spiculated, perpendicular or mixed. There may be multiple layers of subperiosteal reactive new bone, which produces an "onionskin" appearance, which is said to be characteristic. In the early stages of the disease, the disease often needs to be differentiated from non-neoplastic conditions such as osteomyelitis or trauma, since both may produce periosteal reaction with little bone destruction.

Ewing's sarcoma may involve the small bones of hands and feet and even the os calcis [4], though this is rare. In one report of 165 cases of Ewing's sarcoma, only four cases occurred in the feet [2]. Ewing's tumor may cause expansion of bone with a cystic appearance. The entire bone may be involved [1]. In flat bones, the radiological picture is of mottled destruction and patchy reactive sclerosis. The cortex may be destroyed, with thin lamellations; rarely there may be thickening rather than destruction. The lack of lamellated or spiculated periosteal reaction and the absence of cortical thickening are more commonly seen in ES of the hands and feet than at other locations [5]. Absence of periosteal reaction and the lack of cortical thickening were noted in our patient. CT or MR will optimally delineate the osseous and soft tissue extent of the tumor, which is often much greater than may be appreciated on conventional radiographs.

References

1Pritchard DJ. Small round cell tumors. Orthopaedic Clin North Am 1989; 20; 367-375.
2Dahlin DC, Coventry MB, Scanlon PW. Ewing's Sarcoma: a critical analysis of 165 cases. J Bone Joint Surgery (Am) 1961; 43: 185-192.
3Ghelman B. Radiology of bone tumors. Orthopedic Clin North Am 1989; 20: 287-312.
4Greenfield GB. Sarcomas of bone. In: Berman CB, Brodsky NJ, Clark RA eds. Oncological imaging; a clinical perspective. New York: Mc Graw Hill, 1988: 279-306.
5Escobedo EM, Bjorkengren AG and Moore SG. Ewing's sarcoma of the hand. AJR 1992; 159: 101-102.