ADAMANTINOMA-LIKE EWING SARCOMA OF THE PAROTID WITH EWSR1-FLI1 REARRANGEMENT: A CASE REPORT AND REVIEW OF THE LITERATURE

Öz

Adamantinoma-like Ewing sarcoma (ALES) is a rare tumor that shows epithelial differentiation in addition to EWSR1-FLI1 rearrangement. We describe a case of ALES detected as a parotid mass in a 20-year-old woman. This is the thirteenth case of ALES arising in parotid gland. Histopathologically, the tumor consisted of diffuse pattern and solid sheets of basaloid cells with oval, round nuclei, coarse chromatin and scant cytoplasm. Immunohistochemically, tumor cells were positive with CD99, NKX2.2, p40, pancytokeratin and synaptophysin. Additionally, ESWR1-FLI1 rearrangement was demonstrated with FISH. The diagnosis of ALES may be very challenging due to the potential mimics. The precise diagnosis of ALES depends on both morphologic and immunohistochemical findings and has to be supported by molecular analysis determining EWSR1-FLI1 rearrangement.

Anahtar Kelimeler

• Adamantinom-like
• Ewing sarcoma
• ESWR1-FLI1 rearrangement
• parotid

PAROTİSİN EWSR1-FLI1 YENİDEN DÜZENLENMESİ GÖSTEREN ADAMANTİNOMA BENZERİ EWİNG SARKOMU: OLGU SUNUMU VE LİTERATÜRÜN GÖZDEN GEÇİRİLMESİ

Öz

Adamantinoma benzeri Ewing sarkomu (ALES), EWSR1-FLI1 yeniden düzenlenmesine ek olarak epitelyal farklılaşma gösteren nadir bir tümördür. Burada, 20 yaşında bir kadın hastada parotis kitlesi olarak saptanan bir ALES olgusunu sunuyoruz. Bu, parotis bezinde ortaya çıkan on üçüncü ALES vakasıdır. Histopatolojik olarak tümör, oval, yuvarlak çekirdekli, kaba kromatinli ve dar sitoplazmalı diffüz paternli ve solid kitleler oluşturan bazaloid hücre tabakalarından oluşmaktaydı. İmmünohistokimyasal olarak, tümör hücreleri CD99, NKX2.2, p40, pansitokeratin ve sinaptofizin ile pozitifti. Ek olarak, FISH ile ESWR1-FLI1 yeniden düzenlemesi gösterildi. Olası taklitçiler nedeniyle ALES tanısı oldukça zorlayıcı olabilir. ALES'in kesin tanısı hem morfolojik hem de immünohistokimyasal bulgulara bağlıdır ve EWSR1-FLI1 yeniden düzenlemesini belirleyen moleküler analiz ile desteklenmelidir.

Anahtar Kelimeler

• Adamantinoma benzeri
• Ewing sarkomu
• ESWR1-FLI1 rearanjmanı
• ; parotis

Kaynakça

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