A circle in male breast can be caused by gynecomastia, lipoma, folliculitis, localized hyperplasia and other factors. 1. Gynecomastia: hormone level disorder in male body leads to high estrogen content, poor dietary habits, taking certain drugs and other factors can trigger breast development, which can appear as a ring-like hard knot in male breast. 2. Lipoma: when there is lipoma in male breast, there can be ring-like hardness in breast, which is mainly related to the metabolic disorder of adipose tissue, alcoholism and other factors. 3. Folliculitis: when folliculitis occurs in male chest, due to the inflammation and infection caused by the blockage of pores, it can result in the symptom of ring-like hard nodules in male breast. 4. Local hyperplasia: previous history of chest trauma, can lead to breast subcutaneous hematoma, hematoma absorption mechanization, local tissue hyperplasia, can appear in the breast ring ring hard knot. The male breast has a circle should be timely medical treatment, under the guidance of a specialist doctor to actively carry out appropriate treatment, will help the early cure of the disease.