Indications of mammogram in the study.

Background
Retroareolar region refers to the region within two centimeters from the nipple and/or involves the nipple-areolar complex on mammogram. In this study, we graded asymmetric retroareolar density on mammography and determined the underlying cause.
Objectives
To identify and grade retroareolar densities and evaluate characteristics of lesion using ultrasonography and histopathology.
Methods
Mammograms with asymmetric retroareolar density done in our tertiary care hospital were included. Retroareolar density was categorized into three grades based on morphological appearance in mammography. Sonography was performed in all patients and tissue diagnosis was obtained for suspicious lesions.
Results
Of the 100 patients included in the study, most of the patients with mammographic grade 1, grade 2 and 3 retroareolar asymmetry had normal sonography, pathologically proven mastitis and invasive ductal carcinoma, respectively. Presenting indication usually was diagnostic (n = 87), lump being most common. Benign (58%) diagnosis was more often present, with equal number of normal studies and malignancies (21%). Frequently pathologically proven malignant lesions (n = 17) had grade 3 asymmetry and none were grade 1. Invasive ductal carcinoma was the most common malignancy while mastitis the most common benign disease.
Conclusions
Grade I retroareolar asymmetric density on mammography was normal or had a benign etiology while grade 2 or 3 asymmetric density had underlying pathology, often malignancy.
Contribution
Grading retroareolar density in mammogram may improve the evaluation of retroareolar region and increase emphasis on higher grades.