Glycogen-rich clear cell carcinoma of the breast

BACKGROUND: Glycogen-rich carcinoma of the breast is a rare histological subtype of breast cancer, usually reported to have poor prognosis. CASE PRESENTATION: We present the case of a 59-year-old woman who underwent a mastectomy for a 3.5 cm clinically palpable left breast carcinoma, originally diagnosed as fibroadenoma on a screening mammogram four years before presentation. Diagnosis of clear cell carcinoma was based on certain histological characteristics of the tumour and immunohistochemical analysis (PAS staining, keratins AE1/AE3, EMA, cytokeratin 7, cytokeratin 20, melanosomes, vimentin, Chromogranin, Synaptophysin, S-100, SMA). No lymph node metastasis was found and as the tumour was ER positive and PgR negative, patient was treated only with an aromatase inhibitor upfront and remains free of disease 48 months now since operation. CONCLUSION: Glycogen-rich clear cell carcinoma of the breast is a rare tumor, its clinical behavior reported to be rather aggressive so far, might varies depending on special characteristics such as low grade and strongly positive ER expression