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Neuroradiology Case of the Week

Case 75

Ravinder Sidhu MD and P-L Westesson MD, PhD, DDS

Clinical Presentation: A 28-year-old male presented with painful and progressive swelling of the left jaw.

Radiological Findings:  PA and lateral view of the neck showed multiple ill-defined lytic and sclerotic areas involving body and ramus of the left mandible. There was breach in the cortex of the body of the mandible seen inferiorly along with the soft tissue swelling (Fig. 1A&B). The molar teeth were removed due to carious changes as a sequale of radiation treatment. Computed tomography revealed multiple, ill defined hypodense areas with bony erosion in the left mandible (Fig. 2 A&B). Axial T1-weighted MR image showed a heterogeneous intensity signal lesion involving ramus and body of the left mandible (Fig. 3A). Post-gadolinium fat suppressed axial MR image showed irregular peripheral rim enhancement. Areas of low-signal intensity suggestive of necrosis were seen within the lesion. These hypointense signals could represent necrotic changes due to post radiotherapy changes (Fig. 3B).

Diagnosis: Ewing’s sarcoma of the mandible

Discussion:  Ewing’s sarcoma, first described by Ewing in 1921, and also known as diffuse endothelioma of bone or endothelial myeloma, is a highly malignant primary bone tumor that represents approximately 4% to 7% of all primary bone tumors [1]. The long bones and the pelvis are the sites of predilection; involvement of the jaw is rare. However, the mandible is involved eight times more frequently than the maxilla. Ewing’s sarcoma is most commonly seen in the first three decades of life, with highest incidence between 10 and 15 years of age. Men are more often affected than women. Clinically, it presents with pain and local swelling, fever, anemia, increased sedimentation rate and leukocytosis [2].
     The diagnosis of Ewing’s sarcoma is usually suggested on plain radiographs. The radiographic features of Ewing’s sarcoma of the mandible are variable. The most frequent appearance is a coarse permeative destruction of the bone with an extensive soft tissue component. The associated periosteal reaction may be seen, although it is more pronounced in long bones and pelvis [3].
     Conventional radiography is essential for the diagnosis, assessment of tumor aggressiveness, and detection of pathological fractures. Computed tomography has been proven to be valuable in the preoperative evaluation by accurately defining the intramedullary and soft tissue involvement of the tumor, cortical bone destruction, and fine periosteal reaction. Contrast-enhanced MR imaging serves as an important tool for the assessment of most viable parts of the tumor. A diminished signal intensity along with peripheral rim of low signal intensity on T2-weighted images after chemotherapy is an indicator of good histological response [4].
     Ewing’s sarcoma needs to be differentiated from osteogenic sarcoma, osteomyelitis, histiocytosis X, and metastatic carcinoma.

References:

1. Ewing J. Classics in oncology. Diffuse endothelioma of bone. James Ewing. Proceedings of the New York Pathological Society, 1921. CA Cancer J Clin 1972; 22:95-98.
2. Fonseca AS, Mezzalira R, Crespo AN, Bortoleto AE Jr, Paschoal JR. Ewing’s sarcoma of the head and neck. Sau Paulo Med J. 2000; 118:198-200.
3. Hardy P, Gibbs AR. Ewing’s sarcoma of mandible. Br J Oral Maxillofac Surg. 1984; 22:287-294.
4. van der Woude HJ, Bloem JL, Hogendoorn PC. Preoperative evaluation and monitoring chemotherapy in patients with high-grade osteogenic and Ewing’s sarcoma: review of current imaging modalities. Skeletal Radiol 1998; 27:57-71.