The formation of pars plana is caused by congenital developmental abnormalities, mainly due to incomplete degradation of the mammary gland primordia during the embryonic period. During the embryonic period, there are many pairs of mammary gland primordia. Until birth, only one pair of mammary gland primordia in front of the chest develops into a normal breast, while the other mammary gland primordia will degenerate and disappear, and if the degradation of the mammary gland primordia is incomplete, the formation of pars plana may occur. If the breast primordia are not completely degraded, paratesticular breasts may be formed. During pregnancy and breastfeeding, paratesticular breasts may increase in size and become painful. People with discomfort in the paratesticular breasts should consult a doctor in time and standardize the treatment under the doctor’s guidance. Surgical excision is the main treatment. In daily life, avoid squeezing the paratesticular breasts, wear suitable underwear, loose and breathable clothes, and keep a good mindset.