The immunohistochemical profile of mammary tissue in women with macromastia and its potential clinical implications

Abstract Macromastia is an excessive, rapid or slow growth of breast tissue in one or both breasts. While macromastia represents a benign lesion, it may cause breast, shoulder, back and neck pain, poor posture, infections, and loss of nipple sensation. The pathogenesis of macromastia or hypertrophy of mammary tissue remains poorly understood. The purpose of this study is to investigate the immunohistochemical expression of several hormone receptors that may potentially influence the growth of breast tissue in women with macromastia. Immunohistochemical studies performed on representative sections of breast tissue from 63 patients diagnosed with macromastia included estrogen receptor (ER), progesterone receptor (PR), androgen receptor (AR), prolactin receptor (PRLR), growth hormone receptor (GHR), and vascular endothelial growth factor (VEGF). The expression of each stain was evaluated separately in the glandular epithelium and adipose tissue and calculated as an H-score. We observed that AR expression in breast glandular and adipose tissue in women with macromastia was significantly lower compared to benign, non-hypertrophic breast tissue of a control group. Although the analyses were controlled for the age, the fact the mean age and hormonal status differed between the patients and the controls, could have affected the results. Additional large studies will be required to further verify this finding and increase the knowledge about the aetiology of this condition and then guide pharmacological treatment of juvenile and/or idiopathic gigantomastia.