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Sinonasal adamantinoma-like Ewing sarcoma: A case report
Borislav A Alexiev1, Yanki Tumer2, Justin A Bishop3
1Department of Pathology, Northwestern University Feinberg School of Medicine, Northwestern Memorial Hospital, 251 East Huron St, Feinberg 7-342A, Chicago, IL 60611, United States.
Pathology, Research and Practice
|March 7, 2017
Summary
This case study details a rare sinonasal adamantinoma-like Ewing sarcoma. Diagnosis requires molecular analysis due to potential mimics in head and neck tumors.
Area of Science:
- Oncology
- Pathology
- Genetics
Background:
- Sinonasal Ewing family tumors present diagnostic challenges due to numerous mimics.
- Accurate diagnosis is crucial for appropriate patient management and treatment strategies.
Observation:
- A unique case of sinonasal adamantinoma-like Ewing sarcoma in a 41-year-old male is presented.
- Histological examination revealed a nested growth pattern with stromal fibrosis, metaplastic bone, and basaloid cells resembling adamantinoma.
- Tumor cells showed characteristic morphology and strong expression of keratins, p63, CD99, and Fli-1, with EWSR1 rearrangement confirmed.
Findings:
- The tumor exhibited a distinctive histological appearance with adamantinoma-like features.
- Immunohistochemistry confirmed strong expression of CD99 and Fli-1, alongside EWSR1 rearrangement, supporting the Ewing sarcoma diagnosis.
- The presence of cytokeratin expression and focal keratinization did not exclude the diagnosis.
Implications:
- This case highlights the importance of considering Ewing sarcoma in poorly differentiated head and neck tumors.
- Cellular monotony and CD99 positivity warrant molecular studies (EWSR1/FLI1 analysis) to differentiate from other neoplasms.
- Recognizing this rare variant aids in accurate diagnosis and management of sinonasal malignancies.
