Glycogen-rich clear cell carcinoma (GRCC) is a very rare form of primary breast cancer (<0.1% of all breast cancers). It is characterized by the presence of neoplastic cells with a glycogen-abundant clear cytoplasm (the Periodic Acid Schiff–positive, diastase-sensitive). The expression of steroid receptors (estrogen and progesterone receptors) has been variably reported (35% to 100% of the cases), whereas most studies reported low human epidermal growth factor receptor 2 positivity in GRCC. High androgen receptor positivity without androgen receptor splice variant-7 was reported in one recent study. Although sparse, the preliminary theranostic data on GRCC indicate the potential of targeted treatments in selected cases (antiandrogen, PIK3CA, and immune checkpoint inhibitors). Because of its rarity, the prognosis for GRCC patients remains controversial. Herein, we comprehensively appraise the epidemiological, morphologic, molecular, and clinical characteristics of this rare mammary malignancy.

中文翻译：

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富含糖原的乳腺透明细胞癌

富含糖原的透明细胞癌 (GRCC) 是一种非常罕见的原发性乳腺癌（占所有乳腺癌的 0.1%）。它的特点是存在具有糖原丰富的透明细胞质的肿瘤细胞（高碘酸希夫阳性，淀粉酶敏感）。类固醇受体（雌激素和孕激素受体）的表达有不同的报道（35% 到 100% 的病例），而大多数研究报告了 GRCC 中低人表皮生长因子受体 2 阳性。最近的一项研究报告了没有雄激素受体剪接变体 7 的高雄激素受体阳性。尽管数量稀少，但关于 GRCC 的初步治疗诊断数据表明，在选定病例（抗雄激素、PIK3CA 和免疫检查点抑制剂）中具有靶向治疗的潜力。因为稀有，GRCC 患者的预后仍存在争议。在此，我们全面评估了这种罕见的乳腺恶性肿瘤的流行病学、形态学、分子学和临床特征。