Ectopic Mammary Tissue As A Vulvar Mass In A Breast-feeding Woman:a Case Report And Literature Review

Background:The failure of regression of milk line remnants results in the development of an ectopic mammary tissue during embryogenesis. The ectopic mammary tissue can grow anywhere along the milk line, which extend from the axilla to the inguinal regions. The ectopic mammary gland as a vulvar mass is extremely rare among these.Case:We report a25-year-old woman during the lactation, who presented with the chief complaint of a palpable, painless vulvar lump with milky discharge for about1month. On physical examination, there was a round lump, measuring6×5cm, on the right side of the mons pubis. On the ultrasound examination, it was seen that a lobulated echogenic lump with internal septa was in the subcutaneous fat layer of the right mons pubis. Then, the whole mass was excised and the specimen was performed for the histopathological examination, which revealed highly increased secretion of ectopic mammary tissue. By means of the immunohistochemical staining, GCDPF-15is partially positive, and estrogen receptor and progesterone receptor negative. The final diagnosis showed that the vulvar neoplasm was an ectopic mammary tissue. Conclusion:An ectopic mammary tissue in the vulva is a rare case among the accessory breasts, especially in a young and breast-feeding woman. The ectopic mammary tissue can grow anywhere along the milk line, which extend from the axilla to the inguinal regions. The ectopic mammary gland as a vulvar mass is extremely rare among these. In this case, clinical information and its ultrasonography features can contribute to the correct diagnosis of the rare entity, but the pathological confirmation is the gold standard.