Rare Ewing Sarcoma in a Teenager’s Nasal Cavity Erodes the Hard Palate

A striking case report published in the journal Pediatric Radiology has drawn attention to one of the rarest presentations of a well-known childhood cancer: Ewing sarcoma arising in the nasal cavity and eroding the hard palate, the bony shelf that separates the mouth from the nose. The report, authored by radiologists Hao Zhu and Fangansheng Chen of the Third Affiliated Hospital of Wenzhou Medical University in China, describes a 17-year-old girl who arrived with a one-month history of a mass inside her nasal cavity. What imaging and pathology ultimately revealed was a small round-cell tumor confirmed as Ewing sarcoma, an aggressive malignancy that more typically takes root in the bones of the pelvis, femur, or chest wall rather than in the narrow, air-filled passages of the sinonasal tract.

The clinical workup began with contrast-enhanced computed tomography, which revealed a well-defined soft-tissue mass occupying the posterior nasal cavity and showing moderate heterogeneous enhancement after contrast administration. That enhancement pattern matters diagnostically. On CT, tissues take up iodinated contrast in proportion to their vascularity, and many tumors, including sarcomas, display uneven internal blood supply that produces the patchy, heterogeneous appearance seen here. A well-circumscribed border suggested the mass was displacing rather than diffusely infiltrating neighboring structures, yet the location alone could not distinguish between the long list of entities that can present as a nasal mass in an adolescent, ranging from inflammatory polyps and antrochoanal polyps to juvenile nasopharyngeal angiofibromas, lymphomas, rhabdomyosarcomas, and olfactory neuroblastomas.

Magnetic resonance imaging provided the next layer of detail. A sagittal T2-weighted sequence delineated the full craniocaudal extent of the lesion, measuring 30 by 26 by 18 millimeters, and showed a lobulated mass with heterogeneously high signal intensity. T2-weighted imaging is particularly sensitive to water content, and cellular tumors with areas of necrosis or cystic change often light up unevenly. Critically, the sagittal view demonstrated focal destruction of the hard palate, the radiological clue highlighted by the authors in their figure. Bone destruction in the midface is a red flag that shifts suspicion away from benign inflammatory disease and toward neoplasm, because benign polyps remodel and expand bone slowly but rarely breach it. The imaging also reassured the clinical team on a vital point: no metastases were identified at other sites, which is essential for staging in any suspected sarcoma.

Surgical resection followed, and histopathologic examination settled the diagnosis. Under the microscope, the tumor proved to be a small round-cell tumor involving the hard palate bone, without vascular or neural invasion. The term small round blue cell tumor refers to a family of malignancies, including Ewing sarcoma, rhabdomyosarcoma, neuroblastoma, and lymphoma, that share densely packed, primitive-appearing round cells and can be nearly impossible to separate by routine staining alone. Immunohistochemistry resolved the ambiguity: the tumor cells were positive for CD99 and NKX2.2 and negative for myogenic markers. CD99, the product of the MIC2 gene, is a membrane protein strongly expressed in Ewing sarcoma, while NKX2.2 is a transcription factor downstream of the disease’s characteristic genetic driver, making the pair a powerful confirmatory signature. The absence of myogenic markers argued against rhabdomyosarcoma, the other major small round-cell tumor of the pediatric head and neck.

The molecular confirmation came from detection of an EWSR1 rearrangement. Ewing sarcoma is defined genetically by fusion genes in which the EWSR1 gene on chromosome 22 is joined to a member of the ETS family of transcription factors, most commonly FLI1 on chromosome 11 through the t(11;22) translocation. These fusions produce an aberrant transcription factor that reprograms gene expression and drives uncontrolled proliferation of primitive mesenchymal cells. Identifying an EWSR1 rearrangement is considered the gold standard for confirming Ewing sarcoma, because CD99 positivity alone can be mimicked by other tumors. In this patient, the combination of morphology, immunophenotype, and molecular genetics left no doubt.

At three-month follow-up, the patient showed no residual tumor and no metastases, an encouraging early outcome after surgical resection. The authors emphasize the central teaching point of the case: although Ewing sarcoma is rare in the sinonasal region, it belongs in the differential diagnosis whenever an enhancing soft-tissue mass with adjacent osseous destruction appears in an adolescent. That lesson carries real weight, because sinonasal malignancies in young people are uncommon enough that clinicians may initially favor more familiar diagnoses, and delays in recognizing a sarcoma can affect staging and treatment planning for a tumor type in which prompt, multimodal therapy matters.

To appreciate why this case is so unusual, it helps to understand the epidemiology of Ewing sarcoma itself. It is the second most common bone tumor of childhood and adolescence after osteosarcoma, with an incidence of roughly one to three cases per million per year, and it shows a striking predilection for white adolescents, with a peak age range in the early teenage years. The great majority of tumors arise in bone, favoring the pelvis, the long bones of the leg, and the chest wall, where they classically produce a painful, enlarging mass sometimes accompanied by fever and elevated inflammatory markers. Extraskeletal Ewing sarcoma, which arises in soft tissue rather than bone, accounts for a minority of cases, and primary tumors of the head and neck represent only a small fraction of those. Within the head and neck, the most commonly reported sites are the mandible and maxilla, while truly sinonasal primaries confined to the nasal cavity and ethmoid or maxillary sinuses are vanishingly rare, which is precisely why single-case reports like this one contribute to the collective clinical literature.

The radiological features described here also illustrate how modern imaging guides the diagnostic pathway for sinonasal masses. CT excels at showing bony detail, so it is the modality of choice for assessing whether the thin bones of the palate, lamina papyracea, or skull base are eroded, remodeled, or destroyed. MRI, with its superior soft-tissue contrast, maps the tumor’s extent within the nasal cavity, its relationship to the orbit and cranial fossa, and its signal characteristics, and it is indispensable for planning surgical margins. Together, the two modalities in this case localized a lobulated mass to the posterior nasal cavity, quantified its size, and identified the hard-palate erosion that signaled an aggressive process. The heterogeneous enhancement and high T2 signal, while not specific, fit the profile of a cellular sarcoma with variable internal architecture, and the absence of distant metastatic disease on staging evaluation placed the patient in a favorable, localized category.

The immunohistochemical panel used in the case reflects current diagnostic practice for small round-cell tumors. CD99 remains the classic screening marker, but because it can also stain lymphoblastic lymphoma and other entities, pathologists rely on a broader panel: NKX2.2 and FLI1 support Ewing sarcoma, desmin and myogenin mark rhabdomyosarcoma, leukocyte markers identify lymphoma, and synaptophysin or phox2b point toward neuroblastoma. Molecular testing for EWSR1 rearrangement, whether by fluorescence in situ hybridization or next-generation sequencing, then provides definitive confirmation. This layered approach, from imaging to histology to immunophenotype to genetics, is the modern standard for resolving tumors that look identical under the microscope but demand entirely different treatments.

The case, conducted under ethical approval from the Third Affiliated Hospital of Wenzhou Medical University and published with written informed consent from the patient and her legal guardian, ultimately serves as a concise warning wrapped in a single patient’s story. A nasal mass in a teenager that enhances on CT, glows heterogeneously on T2-weighted MRI, and erodes the hard palate should prompt clinicians to keep Ewing sarcoma firmly on their diagnostic list, even though the sinonasal tract is one of the least likely places in the body to find it. Early recognition opens the door to the biopsy, molecular confirmation, and coordinated multidisciplinary treatment that give patients with this aggressive but increasingly treatable cancer the best possible chance of an outcome like this young patient’s early follow-up: no residual tumor, no metastases, and a clean scan three months after surgery.

Subject of Research: A rare sinonasal Ewing sarcoma case in an adolescent with hard-palate bone erosion

Article Title: Sinonasal Ewing sarcoma with hard-palate erosion

Article References: Sinonasal Ewing sarcoma with hard-palate erosion. (n.d.). https://doi.org/10.1007/s00247-026-06808-7

Image Credits: AI Generated

DOI: 10.1007/s00247-026-06808-7

Keywords: Ewing sarcoma, sinonasal tumor, hard palate erosion, pediatric radiology, CT imaging, MRI, CD99, NKX2.2, EWSR1 rearrangement, small round-cell tumor, head and neck cancer, case report