Predicting occult malignancy in nipple discharge.

Background: This study was a retrospective analysis of patients who underwent minor or major duct surgery for pathological nipple discharge. The results of clinical examination, mammography, ultrasonography and cytodiagnosis of the nipple discharge were studied in order to predict those patients at risk of underlying or occult malignancy.

Methods: Between January 2004 and December 2006, 55 female patients aged between 24 and 82 years old underwent major or minor duct excision, 49 of which were for pathological nipple discharge. Results of several preoperative investigations were compared with the surgical pathology to determine how their sensitivity and specificity faired in predicting malignant ductal pathology.

Results: Of the 49 patients undergoing surgery for nipple discharge, 21 were diagnosed with intraductal papilloma, 19 with duct ectasia, 6 with carcinoma, 2 with benign breast disease and 1 with lobular carcinoma in situ. In all of the patients determined to have malignancy, none demonstrated malignant changes on mammography or ultrasonography. Only 2 of the 6 patients with malignancy were found to have atypical cells on cytological analysis. The sensitivity of blood detected in nipple discharge at predicting malignancy was 0.83, specificity of 0.53, positive predictive value of 0.20 and negative predictive value 0.96.

Conclusions: Despite the various tests used in the assessment of pathological nipple discharge, this study highlights their limited help at predicting the cause. This, together with several other studies, demonstrates that ductal surgery remains the only reliable way of providing a diagnosis, in addition to being the major therapeutic measure.