What is the diagnostic value of nipple discharge cytology and galactography in detecting duct pathology?

The present study aimed to evaluate the diagnostic value of nipple discharge (ND) cytology and galactography. Ninety-four patients submitted to duct excision, representing a total of 98 duct excisions, were retrospectively analyzed from January 1997 to May 2007. Histology of ducts excised revealed 35% duct ectasia (DE), 31% duct papilloma (DP), 20% potential malignant transforming lesions (PMTL), 6% breast cancer (BC), 1% adenoma and 6% normal breast tissue. Cytology had a sensibility and specificity in detecting duct pathology of, respectively, 40% and 61.3%, a positive predictive value (PPV) of 53.8% and a negative predictive value (NPV) of 47.5%. Concerning malignant and PMTL, cytology had a sensibility and specificity of, respectively, 46.2% and 62.3%, a PPV of 25% and a NPV of 82.5%. Breast cancer was never suggested by positive cytology. Galactography had a sensibility and specificity in detecting duct pathology of, respectively, 77.4% and 29.2%, a PPV of 58.5% and a NPV of 50%. For malignant and PMTL, galactography had a sensibility and specificity of, respectively, 80% and 26.7%, a PPV of 19.5% and a NPV of 85.7%. However, galactography never suggested a diagnosis of cancer. Cytology and galactography performed together in 49% showed a low Kappa Index (KI < 1), allowing us to conclude that cytology and galactography detect different pathologies. Cytology showed a poor performance in predicting histological diagnosis in face of ND. Galactography had a good sensibility in excluding malignant lesions and PMTL. Galactography was significantly more sensitive for duct pathology but cytology was more specific for malignant lesions and PMTL.