Background: Nipple piercing gains popularity and social acceptance within the last years, especially among young people. The medical literature reports an increase of complications in the post-piercing period. Case report: We report a case of a young woman, who presented with a light enlargment of the right breast and tenderness in the retroareolar region following nipple piercing 5 months ago. On ultrasound, a poorly marginated hypoechoic lesion was seen which was suspicious of an inflammation. After 1 week of antibiotic therapy, the mass had enlarged. As carcinoma could not be excluded, open biopsy was performed. Histology showed signs of chronic mastitis. Conclusion: To date, only a few reports of breast abscess after nipple piercing have been published. With the increasing prevalence of body piercing, it is important to document and report infections which may be discovered many months following piercing. Carcinoma can mimick breast abscess and should be included in the differential diagnosis.