The diagnostic value of nipple discharge cytology: breast imaging complements predictive value of nipple discharge cytology.

Background: Papilloma is the most common finding associated with pathologic nipple discharge. In the absence of breast imaging abnormalities, the incidence of occult malignancy is <3%.

Objective: To determine the predictive value of nipple discharge cytology in conjunction with breast imaging.

Methods: Retrospective review of 160 charts; inclusion criteria of clinically pathologic nipple discharge, subsequent excisional biopsy, and absence of palpable abnormalities. Nipple discharge cytology categorized as negative, atypical, suspicious, and papillary. Breast imaging was analyzed. Preoperative tests were correlated to final surgical pathology.

Results: 89 patients identified. Sixty-five had positive cytology, with a false positive rate of 32.3%. They were associated with papillomas in 52%, benign non-papillary in 33% and malignant lesions in 9% of cases. Nipple discharge cytology was positive in 69.6% of papillomas and 92% of atypical/malignant lesions; 30% had abnormal breast imaging and positive cytology. Nipple discharge cytology had a sensitivity of 74.5%, specificity of 30%, and positive predictive value of 68%. The positive predictive value increased to 85% with associated abnormal breast imaging.

Conclusions: Nipple discharge cytology is useful in evaluating pathologic discharge. However, negative cytology with negative imaging is not enough to avoid surgery in cases of suspicious clinical presentation.