Fine Needle Aspiration Cytology of Glycogen-Rich Clear Cell Carcinoma of the Breast: A Report of Two Cases

Kim, Wan Seop; Lee, Won Mi; Hong, Eun Kyung; Park, Moon Hyang; Lee, Jung Dal

Abstract

Glycogen-rich clear cell carcinoma of the breast is an unusual variant of carcinoma with a recorded incidence of 1.4-3% of breast carcinomas. The cytologic characteristics have not been well described. We report two cases of glycogen-rich clear cell carcinoma with corresponding fine needle aspiration(FNA) cytologic findings and compare them to infiltrating ductal carcinoma and other clear cell malignancies with a review of literature. One was a 62-year-old woman exhibiting a palpable mass of the right breast. The smears showed atypical tight cell clusters and individually scattered single cells containing foamy or clear abundant cytoplasm with well defined cytoplasmic margins. Mild to moderate nuclear pleomorphism and a prominent nucleolus were present. The other was a 42-year-old woman who was admitted with a right breast mass. The smears showed moderately cellular, tightly cohesive tumor cells. The cytoplasmic outline was generally well demarcated. The tumor cells contained foamy to clear abundant cytoplasm with large and small vacuoles. The nuclear pleomorphism was marked. Both tumors resected by modified radical mastectomy, were diagnosed as glycogen-rich clear cell carcinoma. Histologically, the clear cell nature of tumor cells were not characteristic enough to predict this type of the tumor. Some cytologic features can be distinguished other clear cell breast cancer from glycogen-rich carcinoma. Recognition of these unusual patterns in a breast FNAC should raise the suspicion of a clear cell carcinoma including glycogen-rich subtype. Cytological localization of glycogen using PAS and D-PAS staining may permit the correct identification and differential diagnosis of this tumor.