To study the "gray zone" in breast fine needle aspiration cytology in which an unequivocal diagnosis cannot be reached with fine needle aspiration cytology findings.
This study compared cytology and histopathology of 72 breast lesions in which an initial cytologic diagnosis of atypia was given.
There were 36 benign (50%) and 36 malignant (50%) histologic biopsy cases in the cytologic atypia group. Anisonucleosis, chromatin and nuclear membrane irregularity, and presence of myoepithelial cells were significantly different in benign and malignant cases.
The gray zone in breast fine needle aspiration cytology is a broad spectrum that changes from proliferative fibrocystic disease to sclerosing adenosis to malignancy. Diagnosing gray zone pathology as atypical in fine needle aspiration cytology causes no delay in treatment as excisional biopsy is recommended for all equivocal cases.