NUMERO: #20260121

Título: INTRAOSSEOUS EPITHELIOID AND SPINDLE CELL RHABDOMYOSARCOMA WITH EWSR1-TFCP2 FUSION IN THE MANDIBLE

Nome do Apresentador: Wei Cheng LIN

Categoria do Trabalho: Pôster - Relato de Caso ou Série de Casos

Área Temática: Patologia Oral

Resumo: Intraosseous epithelioid and spindle cell rhabdomyosarcoma (RMS) is a rare and aggressive neoplasm associated with TFCP2 rearrangements. A 44-year-old male presented with a 1-month history of a lingual gingival nodule. Histopathology showed highly atypical spindle to epithelioid cells with frequent mitoses and cytokeratin-positive epithelioid nests, mimicking epithelial malignancy, while the spindle component raised concern for sarcomatoid carcinoma. Immunohistochemistry demonstrated diffuse cytokeratin and MyoD1 positivity, with focal desmin and myogenin expression and strong p53 overexpression. Molecular testing identified an EWSR1-TFCP2 fusion, confirming the diagnosis. The patient underwent segmental mandibulectomy with neck dissection followed by adjuvant radiotherapy. Rapid recurrence with multiple distant metastases occurred within six months, and the patient died of disease. This case highlights the diagnostic challenge and the essential role of integrated histopathologic, immunophenotypic, and molecular evaluation.

Autor 1:  Wei Cheng LIN

E-mail 1:  [email protected]

Autor 2:   Yi Ping Wang

E-mail 2:  [email protected]

Autor 3 :  Jen Chieh Lee

E-mail 3:  [email protected]

Autor 4:  Julia Yu Fong Chang

E-mail 4:  [email protected]