[Chondrosarcomatous metaplastic carcinoma of the breast, a rare tumor]. / Carcinoma metaplásico condrosarcomatoide de mama, una entidad inusual.

Metaplastic carcinomas of the breast are uncommon, accounting for less than 0.2% of all breast cancers. Clinically and radiologically, metaplastic carcinomas are indistinguishable from typical ductal carcinomas, and the diagnosis is made histologically by the finding of a mesenchymal component. We present a case of chondrosarcomatous metaplastic breast carcinoma whose definitive diagnosis required immunohistochemical techniques to confirm the malignant epithelial component of the tumor. Accurate diagnosis is important because this tumor behaves differently: it usually spreads through the blood (whereas typical epithelial carcinomas spread through the lymph vessels), metastases present during follow-up rather than before diagnosis, and the five-year survival rate is 35%.

Carcinoma metaplásico condrosarcomatoide de mama, una entidad inusual / Chondrosarcomatous metaplastic carcinoma of the breast, a rare tumor

El carcinoma metaplásico de mama es una entidad infrecuente (menos del 0,2% de todos los cánceres de mama), que se caracteriza por presentar un componente mixto epitelial y mesenquimal. Este último componente es el que establece su clasificación histológica. Así, su diagnóstico es puramente histológico, pues clínica y radiológicamente no se diferencia de un carcinoma ductal típico. Presentamos un caso de carcinoma metaplásico de mama tipo condrosarcomatoide, cuyo diagnóstico definitivo requirió un estudio mediante técnicas de inmunohistoquímica para confirmar el componente epitelial maligno del tumor. Diagnosticarlo es importante porque su comportamiento es diferente, suelen diseminarse por vía hematógena (el carcinoma epitelial típico lo hace por vía linfática), las metástasis no se presentan en el momento del diagnóstico, sino durante el seguimiento, y su supervivencia a los 5 años es del 35% (AU)

Metaplastic carcinomas of the breast are uncommon, accounting for less than 0.2% of all breast cancers. Clinically and radiologically, metaplastic carcinomas are indistinguishable from typical ductal carcinomas, and the diagnosis is made histologically by the finding of a mesenchymal component. We present a case of chondrosarcomatous metaplastic breast carcinoma whose definitive diagnosis required immunohistochemical techniques to confirm the malignant epithelial component of the tumor. Accurate diagnosis is important because this tumor behaves differently: it usually spreads through the blood (whereas typical epithelial carcinomas spread through the lymph vessels), metastases present during follow-up rather than before diagnosis, and the five-year survival rate is 35% (AU)