What Is Ewing Sarcoma in the Oral Cavity?
Ewing sarcoma is a rare yet aggressive lesion or a variant of the small round cell tumors, found in the oral cavity and jaw. This is known to be quite an uncommon malignancy that usually occurs in the first to the second decade of life, that is, in childhood or in young adolescents. It can constitute almost 10 to 15 percent of all global primary malignant or cancerous tumors of the jaw. It represents the second most common cancerous or malignant bone tumor, specifically in children and young adults.
What Is the Categorization of Ewing Sarcoma?
Though it is a known fact in medical research that all primary malignant tumors of the jaws are indeed uncommon, in the few cases globally impacted by Ewing sarcoma, a delay in either detection or treatment of the lesions can prove both challenging and life-threatening. The other small round cell tumors of childhood that belong to the same category as the Ewing family of tumors (ESFT) are rhabdomyosarcoma, lymphoma, desmoplastic small round cell tumors, and others.
These groups of small round cell tumors are not only highly malignant and aggressive but they can be visualized by the oral pathologist microscopically as a monotonous proliferation of small round tumor cells possessing a scanty cytoplasm (that is the characteristic feature or confirmative diagnosis of cancer).
What Is the Terminology, Etiology, and Other Risk Factors of Ewing Sarcoma in the Oral Cavity?
Ewing sarcoma (ES) was first initially described by James Ewing in the year 1920 as it was termed a ‘diffuse endothelioma’ of the jaw bone. This tumor's origin is known to be from the undifferentiated osseous mesenchymal cells, more specifically in adolescents and young adults, usually between the ages of 10 to 20. As per documented case reports, these tumors are rarely seen or reported before the age of 5 years or after the age of 30 years. Males tend to be slightly more commonly affected than females in a ratio of 1.5:1.1 Some preliminary case reports also suggest that Ewing sarcomas can occur among siblings, exhibiting a familial pattern.
The tumor is attributed to have a genetic translocation between the genes 11 and 22 (t;11:22) . This may further give rise to the fusion gene (Ewing sarcoma/Friend leukemia integration 1 transcription factor [EWS/FLI1]) that tends to have a highly potent cancerous or oncogenic action. This gene is primarily known to encode the protein responsible for the formation and growth of this tumor. Ewing sarcoma that originates in the maxillofacial region, that is, either in the upper or lower jaw, usually involves the mandible or lower jaw more often and less frequently the upper jaw or maxilla.
Other risk factors that tend to aggravate the tumor or limit the tumor are based on the site of occurrence, the tumor volume, and the presence of metastases. As the cancer remains untreated or advances further from the jaws, it can cause rapid underlying cortical bone destruction and eventually spread via invasion into the periosteum and oral soft tissues.
What Are the Clinical Features and Diagnosis of Ewing Sarcoma in the Oral Cavity?
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Dentists and pedodontists usually should develop a high suspicion towards the diagnosis of any childhood or adolescent case presenting with a rapidly or progressively enlarging intraoral or extraoral swelling. In most cases of Ewing sarcoma, the overlying oral mucosa affected in the region would usually be of normal appearance only which poses a clinically diagnostic challenge to the dentist or the oral surgeon. Ewing sarcoma can be diagnosed relatively early in any oral location when it presents either with erythema or ulceration of the oral mucosa (that is observed in nearly 12 percent of patients affected).
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Pathological fracture of the jaw can occur as a long-term consequence of untreated Ewing sarcoma lesions of the jaw. The occurrence of a pathological fracture of the jaw would mean that the tumor is extremely aggressive.
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Radiographically, either through OPG (orthopantomography) or through CBCT (cone beam computed tomography), the tumor appears to be radiotransparent with very poorly defined boundaries or limits and no sclerotic reactions. Some cases may also be unique however having a well-defined contour with radiopacity of lesions. One more radiographic challenge in terms of diagnosis is that while most malignant jaw tumors or cancers exhibit a typical onion peel pattern or sunray appearance, In Ewing sarcoma this pattern is completely absent. Hence, the main diagnosis is always confirmed by histopathology staining and microscopy, that is through hematoxylin-eosin (HE) staining. This reveals in ES usually an intense blue color, which is characteristic of the cancer cells and defines the group of small blue round cell tumors.
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Histologic findings need to be correlated with clinical manifestations of the disease such as tooth or dental displacement, premature tooth loss or dental exfoliation, sudden or non-physiological dental mobility, root reabsorption, or even destruction of the dental follicles. These clinical manifestations are consistent with ES patients in the oral cavity, with tooth displacement and mobility being the most common manifestations in almost 40 percent of the cases.
What Is the Management of Ewing Sarcoma in the Oral Cavity?
The standard treatment options considered for localized ES are surgical excision, followed by radiotherapy or chemotherapy. As suggested by the maxillofacial surgeon, it would be sometimes a combination of both radiotherapy and chemotherapy following surgical excision to prevent the recurrence of this aggressive tumor and to eliminate cancer cells to the maximum extent.
Conclusion
Even though most progressive or rapidly enlarging swellings in children or young adults in the jaw region may not be cancers at all, but mostly benign tumors or lesions. It is still important for the dentist to consider such ‘slow-growing lesions’ of the jaw with suspicion. It is always recommended by oral pathologists first to establish a differential and a confirmative diagnosis. Because histologically these tumors are found to be poorly differentiated, they can be quite aggressive in their biologic behavior. Early diagnosis is important and can prove lifesaving to the affected child or young adult and aid in faster treatment and prognosis by the oral surgeon or dentist. The importance of early and proper diagnosis by the dentist or oral surgeon always holds value in the field of medicine, as it can drastically improve not only the clinical management of affected children or young adults but also the survival rates of cancer patients.
