Diagnostic value of nipple cytology: Study of 466 cases

BACKGROUND. Nipple discharge/scraping cytology is a simple, noninvasive method that complements patient assessment. Despite low reported sensitivities for detecting malignancy, the authors predicted that this method would provide important diagnostic information when applied to patients with nonphysiologic nipple discharge or eczematous nipple lesion. METHODS. From 1995-2002, 466 case specimens from 395 patients were evaluated by nipple discharge or scraping cytology. Of the 98 patients with abnormal cytologic findings, histologic follow-up was available for 45 cases (39 patients). After review, each case was categorized as negative or positive for malignancy. Cytologic findings were compared with the findings of subsequent biopsy or excision of the affected duct or nipple lesion. RESULTS. Of the 13 cases of in situ or invasive carcinoma diagnosed by histology, 11 had positive cytology (sensitivity, 85%). Two malignant cases were not represented by preceding cytology and one case with positive cytology failed to demonstrate malignancy after a subsequent biopsy was performed (specificity, 97%). Clinically, all but one case of malignancy was associated with a serosanguinous discharge or eczematous nipple lesion. The cytology of all malignant cases showed dyshesive epithelial cell groups and single cells with prominent nucleoli in a bloody background. The positive predictive value for cytology was 92% and the negative predictive value was 94%. CONCLUSIONS. Cytologic examination of nipple discharge and nipple lesion scrapings is highly specific and sensitive in the detection of carcinoma when applied to patients with unilateral serosanguinous nipple discharge or an eczematous nipple lesion.