Silicone Granulomas

MLO mammographic view of the left breast shows diffuse, markedly increased breast density throughout from prior direct silicone injection for breast augmentation. 

Transverse view of ultrasound of the left breast shows a cystic lesion (arrow) and multiple several lesions that has ill-defined borders and posterior acoustic shadowing (short arrows), representing silicone granulomas.

Axial non contrast CT shows multiple isodense soft tissue nodules in both breasts, some with thin rim of calcifications. 

Breast Augmentation with Direct Silicone Injection

• Was done in the USA in 1950s to 1960s but later prohibited in 1970s by the US FDA
• Liquid form of silicone was directly injected into breast parenchyma
• Adverse effects include lymphadenopathy, infection, formation of granulomatous masses (siliconoma) and fibrosis
• They make cancer difficult to find on physical examination and mammography 

Imaging Appearance of Free Silicone

• Ultrasound: variable appearance including 1) classic = highly echogenic pattern of scattered and reverberating echoes or "snowstorm" appearance, 2) lesion with acoustic shadowing, 3) hypoechoic masses almost indistinguishable from cysts surrounded by echogenic noise
• Mammography: distortion of breast parenchyma with increase density of the breast
• CT: soft tissue nodules with rim calcification
• MRI: low signal intensity on T1W with fat suppression, high signal intensity on T2W with water-suppression

Reference:

Caskey CI et al. Imaging spectrum of extracapsular silicone: correlation of US, MR imaging, mammographic and histopathologic findings. RadioGraphics 1999;19:S39-S51