Breast augmentation belongs to one of the most desired aesthetic surgeries worldwide. Even though silicone implants are used in the majority of breast enlargements, there are still patients treated with injectable fillers. Despite of a less invasive procedure, injectable materials often lead to serious complications. We present a case of a late inflammatory complication 20 years after an injection of unknown filler material. Regardless of early antibiotics treatment, the initial unilateral mastitis spread to the contralateral breast and both supraclavicular and axillar regions leading to a surgical revision and evacuation of the entirely consumed mammary glands. It is a surprising observation of a fast-expanding mastitis two decades after filler application.