21 July 2016
Breast Implant Rupture
- Breast implants may be retroglandular/subglandular (placed deep to glandular tissue) or retropectoral/subpectoral (deep to the pectoralis major muscle).
- A fibrous capsule forms around the implant as a normal physiologic response to foreign material.
- Single lumen implants are the most frequently used device and is composed of a single polymer shell filled with saline or silicone.
- Saline implants have a valve allowing for volume adjustment.
- Saline implants decompress when ruptured and are readily diagnosed clinically.
- Silicone implant ruptures are categorized as intracapsular or extracapsular.
- Intracapsular rupture is contained by fibrous capsule.
- Intracapsular rupture is more common (77% to 89%) than extracapsular rupture.
- Risk of rupture is directly related to age of implant, with most ruptures occurring 10 to 15 years after implantation.
- Median life span of a silicone implant is 10.8 years.
- Most ruptures have no obvious traumatic origin and can present as palpable nodules, asymmetry, tenderness, or may be asymptomatic.
- Imaging:
- Mammogram:
- Intracapsular rupture can be difficult to detect and may present as a contour bulge that can be difficult to differentiate from an implant herniation.
- Extracapsular rupture presents as extruded silicone into the adjacent breast parenchyma or within axillary nodes.
- Tangential views may be helpful in mammographic evaluation of implant rupture.
- Ultrasound:
- 50% to 77% sensitive and 55% to 84% specific.
- Intracapsular rupture presents with the “stepladder sign” — multiple linear/curvilinear lines traversing the interior of the implant at various depths.
- Extracapsular rupture presents with the “snowstorm sign” — free echogenic silicone with well-defined anterior margin and dirty posterior shadowing. Free silicone can be seen in the breast parenchyma or axillary nodes.
- MRI:
- 72% to 94% sensitive and 85% to 100% specific.
- Early sign of intracapsular rupture where the shell has not completely collapsed presents as the “teardrop/keyhole/noose/subcapsular line sign,” which represents a small amount of silicone outside implant but within fibrous capsule.
- Radial folds can appear similar to this sign.
- However, radial folds emanate from the implant surface with silicone on only one side of the shell, while a rupture will have silicone on both sides of the shell.
- More extensive intracapsular rupture presents with the “linguine sign”.
- Extracapsular rupture presents with extruded silicone separate from the implant.
- Mammogram: