Granulomatous mastitis and pectoralis major muscle defect following polyacrylamide hydrogel injection: a case report and literature review

Background: Breast augmentation through the injection of polyacrylamide hydrogel (PAAG) was a popular procedure in the past, but it has since been prohibited due to various complications, including masses, migration, infection, inflammation, and even cancer. However, there were rare cases of granulomatous mastitis with pectoralis major muscle defect following PAAG injection for breast augmentation. Case Description: A 40-year-old female patient presented with a swollen and suppurative mass in her left breast and was insensitive to antibiotics. She was admitted to our department for further treatment after 7 months with progressive local and general symptoms. Ultrasound imaging showed ill-defined heterogeneous echoes, and contrast-enhanced magnetic resonance imaging (MRI) revealed non-mass enhancement lesions in the multiregional distribution in Breast Imaging-Reporting and Data System 4A (BI-RADS 4A) with oedema in the retroglandular space and multiple enlarged lymph nodes in the ipsilateral axilla. Intraoperative observations revealed necrotic tissues, multiple abscesses, residual mucoid PAAG prosthesis diffused into the mammary glands and intramuscularly into the pectoralis muscle, and partial loss of pectoralis major muscle. Histopathological results revealed foreign-body granulomas accompanied by gel-like granular PAAG and proliferative inflammatory cells. She recovered after undergoing the characteristic surgical management in our center under general anesthesia and had no recurrence during the 2-year follow-up. Conclusions: This case revealed that PAAG injection for augmentation mammaplasty, even after the removal operation, could result in subsequent complications, including granulomatous mastitis and pectoralis major muscle damage. PAAG filler complications are difficult to treat, therefore, it is essential to establish appropriate and effective therapeutic procedures.