Table 1 Nipple aspirate fluid cytology classification*
Classification | Characteristics | Interpretation |
|---|---|---|
Unsatisfactory (Category 0) | <10 ductal epithelial cells. | Unsatisfactory specimen. |
Benign (Category I) | Duct epithelial cells within normal limits. Foam cells. Apocrine metaplastic cells. | No malignant cells identified. Benign (non-hyperplastic) ductal epithelial cells present. |
Hyperplasia (Category II) | Minimal changes including slight cell and nuclear enlargement. Chromatin remains finely granular and evenly distributed. Small and regular nucleoli sometimes present. Cell distribution predominately in groups and cohesive with >10–50 cells (papillary and apocrine subcategories). | No malignant cells identified. Benign hyperplastic ductal epithelial cells present. |
Atypical Hyperplasia (Category III) | Moderate to severe abnormalities with distinct nuclear enlargement, increasing nuclear to cytoplasmic ratio, irregular nuclear borders, and nuclear variation. Coarsely granular chromatin. Prominent chromocenters. Cell distribution in groups with some papillary formations. Increased numbers of single atypical cells (apocrine type subcategory). | Atypical hyperplastic ductal epithelial cells present. Malignancy cannot be completely excluded. |
Malignancy (Category IV) | Single cells and groups of cells with unequivocal nuclear features of cancer. | Malignant cells present derived from adenocarcinoma. |