Background: Glycogen-rich clear cell breast carcinoma is a rare histological subtype of breast carcinoma with intermediate-high grade histology, mostly detected as a breast lump with unfavourable prognosis and an aggressive clinical course. Herein is described a case detected on a screening program as two groups of microcalcifications within a non-palpable area of parenchymal distortion in the upper-outer quadrant of the right breast. Fine needle aspiration cytology confirmed malignancy. Distant metastases were ruled out. The patient underwent a quadrantectomy with sentinel lymph node biopsy followed by a modified radical mastectomy. She was alive and disease free four years after conventional chemotherapy.
Materials and methods: Quadrantectomy and mastectomy specimens were processed for routine histology. Three sentinel lymph nodes were analysed in intraoperative consultation and completely submitted for histology. Immunohistochemistry and in situ hybridization were applied on representative samples of tumor.
Results: Quadrantectomy showed multiple scattered foci of white tissue, ranging from <1 mm to 5 mm, in an adipose area of 36 mm in diameter. Both groups of microcalcifications were indistinct on gross examination. Microscopically multiple foci of invasive glycogen-rich clear cell carcinoma grade 2, Nottingham score 7, were observed. High grade intraductal clear cell carcinoma was also present. One sentinel lymph node showed micrometastases. Rare eosinophilic cells were a minor component identified in tumor as well as in micrometastases. Both cell types expressed the same tumor profile. Mastectomy contained residual high grade intraductal carcinoma without axillary metastases.
Conclusions: The aim of this report is to illustrate a clinically silent tumor with an unusual multifocal invasive growth pattern not previously described in this tumor type, with lymph node micrometastases as an early event revealing an aggressive biology. In this case, early detection and treatment favored a good clinical outcome and provided an insight into the development of this histological subtype.