Rabdomiosarcoma alveolar. Dos casos negativos para la fusión PAX3-FOXO1 y PAX7-FOXO1

Resumen Los rabdomiosarcomas son los tumores de partes blandas mas frecuentes en la edad pediatrica y en adultos jovenes. Morfologicamente se distinguen dos subtipos principales: el rabdomiosarcoma alveolar y el rabdomiosarcoma embrionario. El subtipo alveolar se asocia generalmente con un peor pronostico y presenta una fusion genica caracteristica que clasicamente se ha utilizado para confirmar el diagnostico: PAX3/7-FOXO1. Presentamos dos casos que fueron remitidos a nuestro centro. Ambos mostraron morfologia alveolar clasica y diferenciacion muscular basada en la inmunohistoquimica; no obstante, carecian de la fusion caracteristica PAX3/7-FOXO1. El objetivo de este articulo es resaltar l…

Primary cutaneous biphasic sarcomatoid basal cell carcinoma with myoepithelial carcinoma differentiation: A new variant

Isolated cases of basal cell carcinoma (BCC) with partial myoepithelial component have been described. However, myoepithelial differentiation has not been described in sarcomatoid basal cell carcinomas, which usually show features resembling osteosarcoma, chondrosarcoma, or leiomyosarcoma. We report a case of an 87-year-old man with a forehead lesion that histologically showed a minor component of conventional nodular BCC in transition with a major biphasic sarcomatoid growth composed of invasive spindle-cell and epithelial-like components, the latter with a reticular pattern and scattered ductal structures. Both components showed cytological atypia and high mitotic rate (26/10HPF), with at…

Reply to “Primary cutaneous biphasic sarcomatoid basal cell carcinoma with myoepithelial carcinoma differentiation. Is it a new variant of sarcomatoid basal cell carcinoma or a collision tumor composed of a myoepithelial carcinoma and an incidental basal cell carcinoma?”