A case of breast squamous cell carcinoma following breast augmentation with liquid silicone injection after 16 years

BACKGROUND: Breast augmentation has been linked to various complications, including cancerous tumors. The majority type of breast cancer associated with breast augmentation is adenocarcinoma. Primary squamous cell carcinoma (SCC) of the breast is extremely rare in both augmented and non-augmented women. Due to the low incidence, the possible origin and the mechanism of carcinogenesis of the breast SCC are not well understood. Here, we report a rare case of pure SCC 16 years after breast augmentation with liquid silicone injection. CASE PRESENTATION: A 51-year-old Japanese woman was suffered from prolonged breast fluid retention in her left breast. Multiple unknown foreign bodies caused difficulties to investigate the inflammatory focus with ultrasonography. After unsuccessful surgical drainage and antibiotics treatments, the long-standing fluid retention was surgically removed and pathologically investigated. SCC was found in the removed tissue, and the patient underwent a total left mastectomy followed by postoperative chemotherapy. Pathological analysis revealed multiple cystic structures with a hard shell which enclosed high viscous liquid. A qualitative analysis using a Fourier transform infrared spectroscope defined the liquid as pure silicon, which possibly caused the squamous cell carcinogenesis. CONCLUSIONS: Although liquid silicone injection is not a current option for breast augmentation, the injected silicone could result in cancerous tumor generation after years. This case revealed that unphysiological substances could lead to unexpected biological reactions, which caused difficulties in diagnosis with our routine examination. It will be required that accumulate information from more cases and develop novel diagnostic equipment and biomarkers to address these artificial substance-derived tumors.