Ultrasound elastography for the differential diagnosis of nipple retraction

Nipple retraction is difficult to diagnose radiologically and extremely worrisome for patients. It occurs most commonly due to pathologies such as previous mastitis or an infiltrative malignancy. With this in mind, the goal of this study was to differentiate benign from malignant lesions of nipple retraction, using the differential characteristics of retroareolar area stiffness, observed by means of the new technological modality of ultrasound elastography (USE).

Nineteen unilateral nipple retraction cases, including five cases of mammary ductal carcinoma posteriorly infiltrated the areola, two cases of Paget disease, and 12 cases of mastitis, were investigated. Imaging findings [gray-scale ultrasound (US) and USE analyses of the breasts' nipple-areolar complex], pathological evaluation, and the results of 4 years of follow-up treatment were obtained. The recorded images were evaluated by two different radiologists, and all data were analyzed statistically.

Statistical analysis showed that there was a strong correlation between the two radiologists' evaluations. The US images were not diagnostic for either the malignant or benign conditions. The correlation between the diagnosis using US and the final diagnosis was calculated as 0.436 (p = 0.006). However, the USE images were more informative since the correlation ratio between the USE results and the final diagnosis was found to be 0.723 (p < 0.001). While the area under the concentration curve (AUC) values that were used for the diagnostic determination of the US results were inconclusive at 0.274 (p < 0.021), the AUC values for USE were significant, with a diagnostic value of 0.866 for all cases (p < 0.01).

The USE modality, which is not commonly used in routine practice, has the potential to solve the problem of differentiation of nipple retraction etiologies in the near future.