Gel bleed in breast implants

Last revised by Olivia Mauger on 2 May 2023

Gel bleed is a phenomenon associated with silicone breast implants.


Gel bleed refers to the microscopic diffusion of silicone gel through the breast implant elastomer shell. The implant shell, made of silicone, is a semipermeable membrane that allows for the egress or bleed of silicone naturally.

This bleed may be low or high grade, depending on the amount of cross-linking of the silicone elastomer shell.

Radiographic features

Gel bleed is not visible on mammogram or ultrasound. 

On MRI, gel bleed is characterized by the filling of wrinkles ("keyhole sign") present in otherwise intact implants. This is in contrast to the extravasation of silicone resulting from a disruption of the implant shell.

These silicone molecules can travel through the lymphatics, resulting in a "snowstorm sign" 5.

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Cases and figures

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