Calcification of breast implant capsules: incidence, diagnosis, and contributing factors

The Spectrum of Non-neoplastic Changes Associated With Breast Implants: Histopathology, Imaging, and Clinical Significance

Breast implant-associated anaplastic large cell lymphoma has been recognized as a distinct entity in the World Health Organization classification of hematolymphoid neoplasms. These neoplasms are causally related to textured implants that were used worldwide until recently. Consequently, there is an increased demand for processing periprosthetic capsules, adding new challenges for surgeons, clinicians, and pathologists. In the literature, the focus has been on breast implant-associated anaplastic large cell lymphoma; however, benign complications related to the placement of breast implants occur in up to 20% to 30% of patients. Imaging studies are helpful in assessing patients with breast implants for evidence of implant rupture, changes in tissues surrounding the implants, or regional lymphadenopathy related to breast implants, but pathologic examination is often required. In this review, we couple our experience with a review of the literature to describe a range of benign lesions associated with breast implants that can be associated with different clinical presentations or pathogenesis and that may require different diagnostic approaches. We illustrate the spectrum of the most common of these benign disorders, highlighting their clinical, imaging, gross, and microscopic features. Finally, we propose a systematic approach for the diagnosis and handling of breast implant specimens in general.

A Forgotten Entity following Breast Implant Contracture: Does Baker Need a Change?

Although capsular contracture represents one of the most important complications after breast augmentation, local inflammation and fibrosis can lead, in very rare cases, to capsular calcification, an often-forgotten radiological sign of capsular contracture. In this article, the authors present a clinical case of breast implant calcification in an 81-year-old patient. Although this complication has been rarely described, the literature was reviewed to clarify the role of the local microenvironment in capsular contracture and calcification. At present, capsular contracture patients are classified using the conventional Baker score and the histological Wilflingseder classification. As it was not possible to consider capsular calcification when classifying our patient using the traditional scores, the authors propose an updated version of the current scale.

The association of matrix Gla protein isomers with calcification in capsules surrounding silicone breast implants

Implanted silicone medical prostheses induce a dynamic sequence of histologic events in adjacent tissue resulting in the formation of a fibrotic peri-prosthetic capsule. In some cases, capsular calcification occurs, requiring surgical intervention. In this study we investigated capsules from silicone gel-filled breast prostheses to test the hypothesis that this calcification might be regulated by the small vitamin K-dependent protein, matrix Gla protein (MGP), a potent inhibitor of arterial calcification, or by Fetuin-A, a hepatocyte-derived glycoprotein also implicated as a regulator of pathologic calcification. Immunolocalization studies of explanted capsular tissue, using conformation-specific antibodies, identified the mineralization-protective γ-carboxylated MGP isomer (cMGP) within cells of uncalcified capsules, whereas the non-functional undercarboxylated isomer (uMGP) was typically absent. Both were upregulated in calcific capsules and co-localized with mineral plaque and adjacent fibers. Synovial-like metaplasia was present in one uncalcified capsule in which MGP species were differentially localized within the pseudosynovium. Fetuin-A was localized to cells within uncalcified capsules and to mineral deposits within calcific capsules. The osteoinductive cytokine bone morphogenic protein-2 localized to collagen fibers in uncalcified capsules. These findings demonstrate that MGP, in its vitamin K-activated conformer, may represent a pharmacological target to sustain the health of the peri-prosthetic tissue which encapsulates silicone breast implants as well as other implanted silicone medical devices.

The potential calcification of octacalcium phosphate on intraocular lens surfaces

Recently, calcification was observed on implanted intraocular lens (IOL) surfaces when viscoelastic substances were applied during surgery. To elucidate the mechanisms of mineral formation, the crystallization of calcium phosphates on IOL surfaces was studied in vitro with nanomolar sensitivity using a constant composition method. Three different commercial viscoelastic materials (Viscoat, OcuCoat, and Amvisc Plus) were investigated and it was found that some IOLs treated with Viscoat or Amvisc Plus induced the nucleation and growth of octacalcium phosphate crystallites under biological conditions. After treatments, the IOL surfaces became more hydrophilic probably because of the high viscoelastic phosphate and carboxylate contents. In contrast to Viscoat, the use of OcuCoat during surgery resulted in virtually no octacalcium phosphate nucleations. Calcification studies of IOL surfaces treated with fatty acids, which are present in human aqueous humor, suggest that hydrophobic cyclic silicones adsorbed on the IOL surfaces interact strongly with hydrophobic hydrocarbon chains of the fatty acids, creating a layer of amphiphiles oriented with functional carboxylate groups exposed to the aqueous solution and serving as active calcification sites.

Calcification of intraocular implant lens surfaces

Calcification of octacalcium phosphate [Ca8H2(PO4)6 x 5H2O, OCP] on differently packaged "Ultem" and "Surefold" intraocular implant lens surfaces has been studied in vitro in solutions supersaturated with respect to OCP at pH = 7.10 and 37 degrees C. No mineral deposition was observed on the lenses packaged in Ultem vials even after treatment with behenic acid, one of the fatty acids identified on explanted lenses. Following treatment with behenic acid, nucleation of OCP occurred on the lenses from Surefold vials, which incorporate silicone gaskets; induction periods preceding calcification were about 6 h. No mineralization was found on the lenses in vials with other gasket materials, including polytetrafluoroethylene, fluorocarbon elastomer, and polypropylene. The results of this study indicate that both silicone and fatty acids such as behenic acid play important roles in inducing the in vivo calcification of OCP on IOL lenses; all of the lens treatment steps were necessary for nucleation induction.

Liquid- and solid-state high-resolution NMR methods for the investigation of aging processes of silicone breast implants

To investigate aging processes of silicone gel breast implants, which may include migration of free unreacted material from the gel and rubber to local (e.g. connective tissue capsule) or distant sites in the body, chemical alteration of the polymer and infiltration of body compounds, various approaches of multinuclear nuclear magnetic resonance (NMR) experiments (29Si, 13C, 1H) were evaluated. While 29Si, 13C, and 1H solid-state magic angle spinning (MAS) NMR techniques performed on virgin and explanted envelopes of silicone prostheses provided only limited information, high-resolution liquid-state NMR techniques of CDCl(3) extracts were highly sensitive analytical tools for the detection of aging related changes in the materials. Using 2D 1H, 1H correlation spectroscopy (COSY) and 29Si, 1H heteronuclear multiple bond coherence (HMBC) experiments with gradient selection, it was possible to detect lipids (mainly phospholipids) as well as silicone oligomer species in explanted envelopes and gels. Silicone oligomers were also found in connective tissue capsules, indicating that cyclic polysiloxanes can migrate from intact implants to adjacent and distant sites. Furthermore, lipids can permeate the implant and modify its chemical composition.

The peri-implant breast capsule: an immunophenotypic study of capsules taken at explantation surgery

Silicone-based breast implants continue to be the focus of many studies attempting to correlate implant failure to clinical and pathological factors. Routine pathology of peri-implant capsule is extensively described in the literature. The actual significance of the cellular events remains unconfirmed, particularly with reference to clinical outcome. This study reviews our experience with explanted capsules. The study makes specific reference to the immunohistochemistry of the cells participating in the capsule and the significance of the immunophenotypic characterization of these cells to clinical outcome. The use of a wide selection of immunomarkers for T and B lymphocytes and histiocytes provided no supporting evidence for local cell participation in the capsule, which may indicate the presence of an immunological reaction present in the capsule at the time of explantation. One was only able to confirm the presence of a low grade inflammatory process and progression to fibrosis and calcification over time. Statistical correlation was obtained only between Baker grade of capsular contracture and CD3/CD68 immunomarker positivity. CD45RO did show correlation with pain. No correlation was demonstrated with calcification. The results obtained in this study highlighted the need for further investigations into the mechanism of histiocyte and fibrocyte recruitment and activation in the capsule, a possible source of pain and contracture, which is a serious long-term clinical finding leading to the necessity for explantation.

Dual-energy X-ray absorptiometry registers bone mineral in the liver

OBJECTIVE

To analyse the difference in bone mineral content (BMC) between the left and right trunk generally obtained by dual-energy X-ray absorptiometry (DXA) by creating identical images over the liver region and the contralateral side.

PATIENTS AND DESIGN

Fifty-four patients were selected at random from 1,722 subjects examined by DXA because of osteoporosis. Another five patients were selected who had been followed for osteoporosis by repeated DXA two to five times at intervals from 2 to 36 months. One healthy volunteer was followed for one day by means of DXA total body measurements. All protocols were analysed with respect to BMC, fat mass (FM) and lean tissue mass (LTM) of the imaged trunk and liver.

RESULTS

BMC of the right trunk exceeded that of the left trunk in 78% of the investigated subjects. The right (liver) image dominated in all 81 investigations calculated from 60 subjects. There were intraindividual short- and longterm variations between repeated DXA examinations. The amounts of FM and LTM were distributed symmetrically between the right and left trunk.

CONCLUSIONS

DXA registers BMC in the liver, which explains the general dominance of the right trunk. The absorption over the liver region varies in the same individual in repeated measurements at intervals of hours to months.

Calcification properties of saline-filled breast implants

Three patients requested explantation of their saline-filled breast implants. Bilateral calcification had occurred in all six implants. Four of the implants were manufactured by McGhan Corporation (Santa Barbara, Calif.), and two, by the Simaplast Company (Toulon, France). All implants had been inserted in the subglandular plane and had been in place for 7 to 23 years. At the time of explantation, patients were 32, 34, and 44 years old. Calcification on the surface of the implants and capsules was analyzed. Implant surface calcification was clinically evident on all six implants, appearing as ivory-colored, tenaciously adherent deposits, only on the anterior surface of the implant. Capsular calcification, which was observed only microscopically, was characterized by poorly organized, irregularly shaped, calcified agglomerates; this calcification also occurred only on the anterior surface of the capsule, adjacent to the area of calcification on the implant. Ultrastructural analysis of scrapings from the implant surface showed large, electron-dense aggregates of crystals, with individual crystals measuring approximately 40 x 10 x 10 nm. In contrast, capsular calcification was characterized by two patterns of deposition, spherulitic aggregates of needle-shaped crystals and areas of metaplastic bone. The individual crystals were approximately 40 x 10 x 10 nm. Energy-dispersive x-ray spectroscopy of specimens from the areas of calcification on the implant and capsule surfaces demonstrated calcium and phosphorus. Electron diffraction of crystals from the implant and capsule surfaces demonstrated the D-spacings characteristic of calcium apatite. There were many differences between the calcification properties of these six saline implants and those of silicone gel implants. For example, mineralization has not been observed on the surface of gel implants, but in these saline implants it occurred primarily on the implant surface. Also, capsular calcification has been observed clinically in gel implants across the surface of the capsule (except at the site of attachment of a Dacron patch), but in this study it was observed only microscopically and was located on the anterior surface of the capsule, adjacent to the area of calcification on the implant. In addition, crystals 100 times larger than those observed on the six saline implant capsules have been observed on the surface of gel implant capsules. A model is presented to explain the mechanism of calcification associated with breast implants and to explain the observed differences between saline-filled and gel-filled implants.

Current Status of Breast Implant Survival Properties and the Management of the Woman with Silicone Gel Breast Implants

The survival properties of silicone gel breast implants are dependent on their vintage (year of manufacture), duration in situ and manufacturer. A total of 527 gel implants have been explanted and analyzed in the author's laboratories. Of the 28 first-generation implants (1963 to 1972), 27 (96.4%) remained intact after 14 to 28 years in situ (mean 20.8 years). Of the 216 second-generation implants (1973 to mid-1980s) that were explanted from 1992 to 1998, 158 (73%) had disrupted. Kaplan-Meier survival curves demonstrated significantly different survival properties among second-generation manufacturers. Surgitek implants were by far the least durable. After 14 years, all second-generation Surgitek implants had disrupted. By contrast, after 20 years, about half of the Dow Corning and Heyer-Schulte implants remained intact. Among third-generation implants (mid-1980s to 1992), 43 of 46 (93.4%) remained intact after a mean of 6.3 years (range three to 12 years). The three disruptions were Surgitek implants. Implants from other manufacturers remained intact. However, the disruption frequencies of third-generation implants have yet to be measured over the relevant periods of time. Survival patterns appeared to be related to the thickness of the elastomeric shell of the three generations of implants. Mechanical strength analyses of the elastomeric shells of explants have exhibited little or no large scale material degradation, even after as long as 28 years in situ. The mechanism of implant disruption likely involves the ‘fold flaw’ theory, whereby an internal abrasion can develop over time at the site of a fold in the implant wall. Diagnosis of disruption is difficult. Mammography is helpful only if there has been extravasation of silicone gel into breast tissue. Extravasation was observed in only 4.2% of second-generation implants removed from 1992 to 1998. It was not seen with first- or third-generation implants. Ultrasound analyses are not generally helpful to predict disruption because they are very operator dependent and because capsular contracture causes folds in the implant wall, which result in false positives. Magnetic resonance imaging is the most accurate imaging modality to detect implant disruption. However, this technology is not indicated for monitoring implant status because it is too costly and time consuming, and because it has significant limitations, particularly with first-generation and textured implants. Careful explantation and direct visual examination are the standards for diagnosing gel implant disruption. Many implant disruptions are likely ‘silent’, with no specific symptoms or clinical findings. After disruption, none of the following are elevated above the levels seen in control women without implant exposure: serum autoantibodies, blood and serum silicon, and the incidence of breast cancer, autoimmune disease or any other medical disease. There is no evidence to support the existence of any ‘novel’ or ‘atypical’ syndrome associated with gel implants. Women over 30 years of age with breast implants require regular monitoring for breast cancer detection. This should include monthly breast self examination and annual clinical breast examination. In addition, women over 50 years old require annual eight-view mammographic assessment using the implant displacement technique. Even then, breast implants have been shown to interfere with complete imaging, particularly if the implants are subglandular, large or associated with significant capsular contracture. A logical approach to explantation should involve consideration of a patient's personal concerns and anxiety, her implant vintage, the plane of insertion of her implants, her current clinical status and whether she chooses to replace her gel implants. Women requesting explantation require extensive information before deciding on surgery. At explantation, capsulectomy seems to be indicated if there is capsular calcification or major capsular thickening. (Pour le résumé, voir page suivante)

The immunopathology of siliconosis. History, clinical presentation, and relation to silicosis and the chemistry of silicon and silicone

Recent evidence confirms the fundamental involvement of the human immune system in the reaction to implantation of silicone-based medical devices. An as yet-to-be particularized epitope of many complex substances sharing siloxane structures is presented through the MHC-II apparatus with development and retention of T cell memory. This memory can be tested for in practical terms using one or more forms of silica, which links the immuno-histopathology and autoimmune attributes of "silicosis" with those of "siliconosis." The lesions of siliconosis are typical of those for persistent antigens and delayed, cell mediated hypersensitivity. The basic descriptive pathology of the reaction to silicone has been known since soon after introduction of silicones in medical procedures, with the exception of some details related to the more recent discoveries on the role of cytokines in the immunopathic process. The clinical consequences of siliconosis are common and can be severe in some individuals implanted with silicone devices.

Silicone breast implants: complications

Silicone breast implants have been used for augmentation mammoplasty for cosmetic purposes as well as for breast reconstruction following mastectomy for more than three decades. Though the use of the silicone gel filled variety has been banned in the USA except for special cases, they continue to be available elsewhere in the world including the UK. Despite the immense benefit they provide, their usage is associated with some complications. Most of these are related to the surgery and can be reduced by good surgical management. The major complications associated with their use is adverse capsular contracture, an outcome which can be very frustrating to manage. This article reviews the commonly reported complications and suggested management alternatives.

Heterogeneous nucleation of calcium phosphates on solid surfaces in aqueous solution

The heterogeneous nucleation of calcium phosphates on solid surfaces of poly(methyl methacrylate) (PMMA), poly-(tetrafluoroethylene-co-hexafluoropropylene) (FEP), silicone rubber, mica, and radiofrequency glow discharge (RFGD)-treated PMMA, FEP, and silicone rubber has been studied in solutions supersaturated with respect to hydroxyapatite. The surface properties of the substrates were characterized by contact angle measurements. For the RFGD-treated surfaces, the Lifshitz-Van der Waals surface tension component changes very little, but the Lewis acid-base surface tension parameters vary greatly depending upon the materials. With scanning electron microscopy, nucleation of calcium phosphates was observed only on the surfaces: mica, RFGD-treated PMMA and FEP, with relatively high values of the Lewis base surface tension parameter. The more hydrophobic surfaces having low Lewis acid-base surface tensions, untreated PMMA and FEP, silicone rubber, and even RFGD-treated silicone rubber showed no nucleation.

Role of mammography to assess complications of silicone gel breast implants

Mammography is not accurate to predict implant rupture in most patients. Its sensitivity rate is only 11 to 16%. However, two mammographic findings appear to suggest implant rupture: the appearance of large areas of implant herniation, and the appearance of silicone globules lying outside the margins of the implant. Mammography is also helpful to predict capsular calcification and to assess certain complications of retained breast implant capsules. Two patients presented with retained capsules which had not resolved, two and five years after implant removal. One patient developed a spiculated mass, suspicious for carcinoma, that proved to be a cystic mass resulting from persistent serous effusion. The other patient demonstrated a large densely calcified capsule which interfered with breast imaging.