Fine needle aspiration cytology of glycogen-rich clear cell carcinoma of the breast. A case report.

BACKGROUND: Glycogen-rich clear cell carcinoma (GRCC) is a rare variant of breast carcinoma that was first described by Hull et al in 1981. The histologic findings have been described; however, the cytologic characteristics have not been well described.

CASE: A 44-year-old female exhibited a palpable mass in her right breast. The fine needle aspirate contained cell clusters in a necrotic background. In addition to carcinoma cells with increased degrees of nuclear atypia, carcinoma cells with less atypia were identified. The tumor cells contained small round or ovoid nuclei and abundant, clear cytoplasm. The tumor, resected by modified radical mastectomy, was diagnosed as GRCC with detection of glycogen accumulation in the cytoplasm.

CONCLUSION: Although rare, glycogen-rich clear cell carcinoma should be considered in the differential diagnosis of breast cancer in fine needle aspiration cytology to prevent misdiagnosis because of its varied morphologic patterns and less atypical cytologic features.