Low-grade triple-negative breast carcinomas. A report of 2 cases and an update of current concepts.

Triple negative breast cancer is defined by the lack of expression of estrogen, progesterone and HER2 receptors. Significant molecular, morphological and clinical heterogeneity is present in this group of neoplasms. Although the majority are high-grade tumors, low-grade triple negative breast cancers can occur and their evolution, molecular characteristics and therapeutic management vary from the former. In the current review, we focus on the histological and immunohistochemical phenotypes of two new low-grade cases: an acinic cell carcinoma and an adenoid cystic carcinoma. Data originated from the pathology department of a third-level hospital over an 18-month period, within a breast cancer screening program. Low-grade triple negative cancers should be suspected in triple negative breast cancers with low proliferative rates as, unlike high-grade tumors, they require a multidisciplinary approach. They can be diagnosed at an early stage by immunohistochemistry using core needle biopsy.

Low-grade triple-negative breast carcinomas. A report of 2 cases and an update of current concepts

Triple negative breast cancer is defined by the lack of expression of estrogen, progesterone and HER2 receptors. Significant molecular, morphological and clinical heterogeneity is present in this group of neoplasms. Although the majority are high-grade tumors, low-grade triple negative breast cancers can occur and their evolution, molecular characteristics and therapeutic management vary from the former. In the current review, we focus on the histological and immunohistochemical phenotypes of two new low-grade cases: an acinic cell carcinoma and an adenoid cystic carcinoma. Data originated from the pathology department of a third-level hospital over an 18-month period, within a breast cancer screening program. Low-grade triple negative cancers should be suspected in triple negative breast cancers with low proliferative rates as, unlike high-grade tumors, they require a multidisciplinary approach. They can be diagnosed at an early stage by immunohistochemistry using core needle biopsy.(AU)

El cáncer de mama triple negativo se define por la falta de expresión de receptores de estrógeno, progesterona y HER2. La heterogeneidad molecular, morfológica y clínica en este grupo de neoplasias es significativa. Aunque la mayoría de ellos son tumores de alto grado, existen cánceres de mama triple negativos de bajo grado cuya historia natural, características moleculares y terapia óptima son bastante diferentes a los primeros. En la revisión actual, nos centramos en los fenotipos histológicos e inmunohistoquímicos de 2 nuevos casos de bajo grado: un carcinoma de células acinares y un carcinoma adenoide quístico de bajo grado. Los datos provienen de los diagnósticos realizados por el servicio de anatomía patológica de un hospital terciario durante un período de 18 meses, dentro de un programa de cribado de cáncer de mama. Los cánceres triple negativos de bajo grado deben sospecharse en los cánceres de mama triple negativos con bajas tasas de proliferación y podrían ser diagnosticados precozmente por inmunohistoquímica en biopsia con aguja gruesa, ya que requieren un abordaje multidisciplinario, diferente a los de alto grado.(AU)