Low-Grade Invasive Triple Negative Breast Carcinoma

Abstract

Triple-negative breast carcinomas (TNBCs) are defined as estrogen receptor-negative, progesterone receptor-negative, and human epidermal growth factor receptor 2-negative breast carcinomas and are composed of a heterogeneous group of breast carcinomas with most of them having aggressive behavior and poor prognosis. However, some TNBC cases are low grade with indolent clinical outcome and low risk of metastasis to other organs or regional lymph nodes. Lowgrade TNBCs include low-grade adenosquamous carcinoma, fibromatosis-like metaplastic carcinoma, low-grade invasive (ductal or lobular) carcinoma with apocrine differentiation, classic adenoid cystic carcinoma, secretory carcinoma, tall cell carcinoma with reversed polarity, acinic cell carcinoma, and low-grade mucoepidermoid carcinoma. This review aims to summarize the clinicopathological correlation and the molecular features of low-grade special TNBC subtypes.