Keywords: Incidental findings - Breast - Magnetic resonance imaging - Silicone elastomers -
Breast implants
INTRODUCTION
The breasts are of fundamental importance in the patient’s psychosexual
well-being, since the desire to improve aesthetic appearance is part of
self-care, whether to reverse sagging, increase volume, rejuvenate, correct
asymmetry, or reconstruct the breasts[1 ]. Thus, the implantation of breast prostheses is one of
the most performed surgeries in the world, according to data released by the
International Society of Aesthetic Plastic Surgery (ISAPS), representing around
15.8% of aesthetic surgical interventions carried out in 2018,
worldwide[2 ].
In 1889, Gersuny described breast augmentation with paraffin injection into the
breast parenchyma. Over time, various materials have been used to reconstitute
breast volume, such as ivory prostheses, sponges of different compositions,
dermal-fat grafts, liquid silicone, or gel[3 ].
The introduction of silicone breast implants began in 1963, in the United States
of America, through Cronin and Gerow, and since then the aforementioned surgical
intervention has been the subject of great discussion[4 ]
[5 ]. The
initial conception aimed at aesthetic surgeries, but currently the field of
breast reconstruction uses implants on a large scale[6 ]. The first implants were manufactured with thick
elastomer, in two halves, which were glued together to form a single piece. Over
time, several evolutionary steps were overcome[7 ]
[8 ].
Sperli described 7 evolutionary phases of breast implants that depend on the type
of wrap, with or without patch, coating, and inflatable prostheses[9 ]
[10 ]. For most types of implants and styles, there have been
variations over the years, with single-lumen gel-filled implants being more
common in our country[6 ].
Despite improvements in surgical techniques and the safety of current implants,
patients are still faced with potential complications, the most frequently
encountered of which are hematomas, seromas, infections, asymmetries, rippling,
and especially capsular contractures, which are still the most commonly seen
complications. with a global incidence of around 27%, associated with the use of
smooth and textured implants from the first generations of prostheses[11 ]
[12 ]
[13 ].
Although mammography and ultrasound are the exams initially requested for
investigation, nuclear magnetic resonance (NMR) is the most useful imaging
modality for characterizing breast implants, due to its high spatial resolution
and the provision of a contrast image between the implant and surrounding soft
tissues[14 ]. Another
advantage is the absence of ionizing radiation. NMR has greater sensitivity
(72-94%) and specificity (85-100%) to detect implant ruptures, thanks to its
sequences that can suppress or emphasize the signal from the silicone[3 ].
In the MRI protocol, high-resolution devices, the internal composition of the
silicone is better visualized with details in a sagittal T2 FSE (Fast spin echo)
image, and the high-quality T2 image with water suppression can be useful to
differentiate the silicone with intracapsular rupture from the peri-implant
fluid[15 ]. Two-plane
imaging is indicated to differentiate early intracapsular ruptures from folds
formed at the bottom and top of the implant. Furthermore, imaging in the
anteroposterior plane is not recommended due to artifacts caused by the heart
and chest[15 ].
Unusual complications may occur, such as intracapsular and extracapsular
ruptures, late hematomas, and contour deformities, with magnetic resonance
imaging being the gold standard image evaluation for diagnostic
elucidation[16 ].
Seromas are uncommon late complications, but can occur without a defined cause,
the treatment of which involves the removal or replacement of
prostheses[17 ]. The
appearance of a large seroma more than one year after implant placement is
defined as late. In prospective studies, it was estimated that breast
implant-related anaplastic large cell lymphoma (BIA-ALCL) is common in late
seroma presentations[18 ]. In the
event of a late seroma that is not easily explained by infection or trauma, the
disease should be considered suspected[19 ].
The most common type of rupture is that of the implant shell (elastomer
envelope)[20 ], the leak
of which does not extend beyond the fibrous capsule that commonly forms around
silicone implants, accounting for 80 to 90% of all intracapsular implant
ruptures [5 ]. Extracapsular
rupture is defined as the extrusion of both the shell and the fibrous capsule,
with macroscopic silicone leakage[21 ]
[22 ]
[23 ].
OBJECTIVE
To survey the changes found in MRI scans of patients with silicone implants, and
identify unusual findings and their frequencies in a large radiology
service.
METHOD
A retrospective survey was carried out in the registry of a private radiology
clinic in Brasília-DF of exams carried out on patients with silicone implants
between April 2015 and March 2023.
This is a series of cases in which patients with alterations were identified and
the so-called “unusual” alterations were selected, due to their low frequency or
absence of citation in the literature, after surgeries to include a silicone
prosthesis. Patients who underwent breast augmentation using implants for
aesthetic purposes or breast reconstruction were included in the study.
The reason for carrying out the exam was not the subject of the study. A survey
of nuclear magnetic resonance (NMR) reports and images was carried out and those
that showed unusual findings were selected for study. Furthermore, a literature
review was carried out on each of the cases described and listed below.
Finally, it should be noted that the present study followed the principles
contained in the Declaration of Helsinki, developed by the World Medical
Association. Furthermore, the work was submitted and approved by the Ethics and
Research Committee, under number 75934023.7.0000.0257.
RESULTS
211 patients with breast implants underwent MRI and changes were found in 12,
which corresponds to 5.68% of the total. A classification into 3 groups was
used:
Group 1, with a total of 5 patients: 5 patients (2.3%) presented a large amount
of pericapsular fluid, 3 of which were cases of pericapsular seroma, submitted
to aspiration punctures and CD30 and ALK1 measurement, considering the
possibility of IABP -ACL, with 1 positive patient. Others 3 patients (1.4%) had
capsular granuloma and 1 patient (0.4%) had late capsular seroma with
hemorrhagic content.
Group 2, with a total of 3 patients: 2 patients (0.9%) had axillary lymph node
disease; 1 patient (0.4%) had intra and extracapsular rupture; 1 patient (0.4%)
had a nodule close to the fibrous capsule of the implant; 1 patient (0.4%)
ipsilateral axillary lymph node disease of probable inflammatory/infectious
origin and 1 patient (0.4%) intra-nodal silicone.
Group 3, with a total of 4 patients: 1 patient (0.4%) with pectoral muscle edema,
2 patients with desmoid tumor, and 1 patient (0.4%) with herniation of the
fibrous capsule.
Case 1
B.A.L.I., female, 25 years old, states that 5 years ago she underwent surgery
to place a prosthesis for aesthetic purposes for breast augmentation. She
underwent surgery with the apposition of implants in the retroglandular
plane. Radiological finding: bilateral pericapsular fluid, in greater
quantity on the right, associated with enhancement of the fibrous capsule.
Given the possibility of BIA-A.L.C.L., the investigation continued with
ultrasound-guided needle aspiration, yielding a positive result.
Case 2
D.G., female, 69 years old, reports that she underwent breast reconstruction
surgery after a bilateral mastectomy with silicone implants in the
retromuscular plane. An MRI examination was performed with the finding of a
large pericapsular seroma on the right, suspicious for BIA-ALCL, a capsular
nodular image with heterogeneous enhancement, but probably corresponding to
an induced silicone capsular granuloma. Furthermore, there was a
morphological change in the right prosthesis compatible with capsular
contracture.
Case 3
R.C.M., female, 71 years old, 22 years ago she underwent aesthetic breast
surgery with a silicone implant in the retroglandular plane. A routine
examination revealed a large pericapsular seroma with
hyperproteic/hemorrhagic content on the right. FNAB was performed,
considering the possibility of BIA-ALCL. After this MRI examination, this
patient underwent bilateral capsulectomy surgery, with clot removal on the
right and breast reconstruction 1 year ago.
Case 4
J.M., female, 62 years old, states that 6 years ago she underwent breast
augmentation surgery with implants placed in the retroglandular plane. MRI
revealed a nodule next to the fibrous capsule of the left implant of
non-specific origin, which may correspond to a granuloma.
Case 5
K.A., female, 55 years old, undergoing reconstruction surgery due to a right
mastectomy. An MRI performed revealed enhancement of the breast parenchyma
and implant capsule on the left, associated with non-specific ipsilateral
axillary lymph node disease, probably inflammatory/infectious.
Case 6
R.C.S., 66 years old, states that 11 years ago she underwent cosmetic surgery
for breast augmentation with a retroglandular silicone prosthesis. MRI
showed that the left implant showed signs of capsular contracture. Absence
of signs suggestive of intra and extracapsular rupture of the implants.
Case 7
A.S., 46 years old, female, underwent aesthetic silicone breast implant
surgery in the retroglandular position 10 years ago. Presents silicone in
the right breast with a moderate amount of pericapsular fluid, in addition
to thickening and diffuse enhancement of the fibrous capsule.
Case 8
C.A.M., 52 years old, female, underwent breast reconstruction surgery due to
bilateral adenomastectomy using double lumen breast expanders, with signs
suggestive of intracapsular rupture on the left. In addition, on imaging
exams, left axillary lymph node enlargement is presented, with a
heterogeneous signal, which may correspond to intra-nodal silicone,
suggesting ipsilateral extracapsular rupture.
Case 9
E.R., 49 years old, female, underwent cosmetic surgery 2 years ago with a
breast implant in the retroglandular plane. Imaging examinations showed
marked thickening and diffuse pericapsular enhancement, associated with
morphological changes, a large pericapsular seroma, and edema of the
underlying pectoral muscle, with pre-sternal extension to the medial aspect
of the fibrous capsule and contralateral pectoral muscle.
Case 10
C.M., 47 years old, female, underwent breast reconstruction surgery with
prosthesis in the submuscular plane. On magnetic resonance imaging of the
breasts, a breast expander on the right of the usual shape, without signs of
rupture, with diffuse capsular enhancement. In the inferolateral quadrant of
the right breast, there is a herniation of the fibrous capsule with
heterogeneous contents.
Case 11
B.K.A., 30 years old, female, underwent mammoplasty with the inclusion of
implants, for aesthetic purposes. One year after surgery, a hardened area
was noticed in the left breast. Magnetic resonance imaging was performed,
finding a heterogeneous nodulation in close contact with the implant
capsule, with a positive result for desmoid tumor.
Case 12
L.M.F., 54 years old, female, underwent aesthetic surgery with an implant in
the retroglandular plane. She reported nodulation in the left breast, which
presented an irregular and spiculated appearance on MRI, with a result
compatible with a desmoid tumor.
DISCUSSION
Faced with several complications related to breast implants, magnetic resonance
imaging is the method of choice for evaluating the integrity of silicone
implants, as it is more accurate than mammography and ultrasound, chosen for
monitoring and cancer screening[6 ]. With a sensitivity of up to 94% in detecting rupture and
specificity between 85% and 100%, sequences with and without silicone
suppression are used, as well as combined sequences to evaluate parenchyma and
prosthesis[24 ].
In the evaluation of lesions in the breast parenchyma, paramagnetic contrast can
be used, which has better accuracy in recent post-operative breasts, due to the
architectural distortion and edema of the operated breast[24 ]. This usual change is seen
when capsular contracture occurs, after breast augmentation with silicone. The
thin fibrous capsule normally forms around the prosthesis and causes discomfort
and deformity in the breast architecture[15 ].
There are several signs found on MRI that correspond to complications of silicone
implants, with findings compatible with extracapsular rupture (keyhole sign or
noix sign) being described in the literature[6 ]. Furthermore, on the sagittal-weighted image, the
subcapsular line signal corresponds to the intracapsular tear. This sign is
known as salad oil (foci of hypersignal on T2 inside the prosthesis)[24 ].
Two patients presented intracapsular rupture, as shown in [Figure 8C ], which depicts the linguine sign, and the
presence of several hypointense curvilinear lines within the silicone gel.
The radiological sign of capsular contracture shown in [Figures 1C ] and [2D ] can
be analyzed as an increase in the anteroposterior diameter of the implant,
associated with its asymmetry and rounded shape[8 ].
Figure 1. A and B. Axial T2 sequences show a large bilateral pericapsular
seroma, slightly larger on the right. C. Post-contrast T1 sequence
in axial plane showing slight thickening and enhancement of the
fibrous capsule (arrows).
Figure 2. A. Axial T2 sequence showing a large pericapsular seroma on the
right, slightly hyperproteic. B and C. Post-contrast T1 (B) and T2
(C) sequences in the axial plane show hyperintense capsular nodular
image on T2 and with heterogeneous and persistent enhancement on the
posterior aspect of the right implant, suggestive of induced
silicone capsular granuloma (arrows). D. Post-contrast T1 sequence
in axial plane showing changes in the morphology of the right
implant, with a reduction in lobulations associated with thickening
and diffuse and irregular pericapsular enhancement, suggestive of
capsular contracture.
Large late seromas were found in group 1 and are exemplified in [Figures 1A ], [1B ], [2A ], and [3C ]. In the literature, possible etiological
assumptions point to rupture of the prosthesis, which did not occur in any
case[25 ]. However, in
prospective studies, it was estimated that BIA-ALCL occurs in 9 to 13% of late
seroma presentations[17 ]. But
this fact could be justified by other causes, such as, for example, friction
between the prosthesis and the organic pocket, the chronic inflammatory process,
and metaplasia of the internal surface of the capsule[10 ].
Figure 3. A, B, and C. Post-contrast T2 (A and B) and T1 (C) sequences in
the axial plane show a large heterogeneous hyperproteic pericapsular
seroma on the right and diffuse pericapsular thickening and
enhancement. D and E. Post-contrast T1 (D) and T2 (E) sequences in
the axial plane showing hyperintense capsular nodular image on T2
and with heterogeneous and persistent enhancement in the left
implant, suggestive of induced silicone capsular granuloma
(arrow).
Pinchuk & Tymofii[26 ], in a
series of 569 patients who had breast implants, reported 6 cases of late seroma,
occurring between 2 years and 10 years postoperatively. In the authors’ opinion,
the friction of the prosthesis against the internal surface of the organic
capsule was one of the main reasons for synovial metaplasia on this surface, but
also chronic infection and the consequent formation of seroma.
Lymphatic drainage of the breast occurs mainly via 3 routes: supraclavicular,
axillary, and internal mammary, justifying the local lymphadenopathy in cases of
prosthesis rupture[27 ], similar
to what occurred in case 8 and demonstrated in [Figure 8D ]. Silicone lymphadenopathy is an unusual finding on MRI and
has a poorly understood mechanism. However, it is believed that silicone
particles are transported to lymph nodes via macrophages in the
reticuloendothelial system. In these cases, the diagnosis of breast cancer must
be excluded[25 ].
Unlike rupture, silicone gel leakage is microscopic through an intact implant
shell. This phenomenon is related to the chemical affinity between the outer
layer of the silicone elastomer and the gel contained therein[14 ]. Contact with the outer shell
can disrupt non-covalent molecular bonds between polymer chains, causing
swelling and weakening of the shell itself. Once separated from its envelope,
the silicone can migrate, reaching the upper limbs, inguinal lymph nodes, and
pleural fluid. Thus, the possible change in two patients in group 2 with
axillary lymph node disease and intra-node silicone can be explained. When gel
extravasation is extensive, it can be detected by imaging examination, resulting
in the formation of the inverted tear sign[6 ]
[10 ].
Capsular granuloma was evident in two patients, as seen in [Figures 2D ], [4A ] and [4B ]. Furthermore, edema of the pectoral
muscle was noted in one patient, as shown in [Figure 9A ]. The changes in question can be explained by the
literature. In this case, the implant’s silicone gel may have its envelope
dissolved over time, making its coating thinner, or even dissolved completely,
which makes the product viscous inside the organic fibrous capsule. Thus, in
certain cases, there is migration of the viscous product to neighboring tissues,
which can form granulations, inflammation of the skin with skin rash, urticaria,
calcifications, migration to lymph nodes, or even infiltration into chest
muscles, simulating tumors[25 ].
Figure 4. A and B. Post-contrast T1 (A) and T2 (B) sequences in the axial
plane showing hyperintense capsular nodular image on T2 and with
heterogeneous and persistent enhancement on the left implant,
suggestive of induced silicone capsular granuloma (arrow).
Figure 5. A, B, and C. Post-contrast T1 sequences in the axial plane
showing enhancement of the breast parenchyma in the posterior third
of the medial quadrants of the left breast, next to the breast
implant, associated with enhancement of the fibrous capsule and
local skin thickening and enhancement. D. 3D MIP reconstruction
(maximum intensity projection) in the sagittal plane demonstrating
these findings.
Figure 6. A and B. Axial T2 sequences showing heterogeneous pericapsular
seroma on the left (arrows), in addition to reduced lobulations of
this implant. C. Post-contrast T1 sequences in the axial plane
showing thickening and diffuse enhancement of the fibrous capsule of
the left implant (arrow).
Figure 7. A and B. Axial T2 sequences showing heterogeneous pericapsular
seroma on the right (arrows). C. Post-contrast T1 sequence in axial
plane showing thickening and diffuse enhancement of the fibrous
capsule of the right implant (arrow).
Figure 8. A, B, and C. Axial T2 sequences showing tiny liquid inclusions in
the left implant (A and C) and “linguine sign” (B), suggestive of
intracapsular rupture of the external lumen. D. T1 sequence in axial
plane showing left axillary lymph node enlargement, with a
heterogeneous signal similar to that of silicone (arrow), which may
correspond to intra-nodal silicone and suggest ipsilateral
extracapsular rupture.
Figure 9. A. T2 sequence in the axial plane showing loss of lobulations and
rounded morphology of the right implant, associated with a
pericapsular seroma displacing this implant anteriorly, in addition
to diffuse edema of the underlying pectoral muscle (arrow) and the
medial aspect of the contralateral pectoral muscle (arrow). B, C,
and D. Post-contrast T1 sequences in axial (B and C) and sagittal
planes (D) showing marked thickening and irregular diffuse
pericapsular enhancement of the right implant, especially in its
posterosuperior aspect (C and D - arrow), with pre-sternal extension
towards the fibrous capsule of the contralateral implant (B - arrow)
and associated with thickening and faint skin enhancement in the
lower and medial quadrants of the right breast.
Figure 10. Post-contrast T1 sequences in the axial plane (A and B) and T2
sequences in the axial plane (C and D) showing herniation of the
fibrous capsule with heterogeneous content in the inferolateral
quadrant of the right breast (arrows). E. Post-contrast T1 sequence
in sagittal plane showing the subcutaneous location of the
herniation, in close contact with the skin (arrow).
Desmoid fibromatosis (DF) is a non-metastatic, rare, locally aggressive
myofibroblastic tumor, with high recurrence rates (24-77%) and an unpredictable
clinical course. The incidence is approximately 0.2% of all breast
neoplasms[28 ]. The most
affected site is intra-abdominal, with the breast being an extremely rare
condition[29 ]. Two
patients were found in whom the hypothesis of malignant breast tumor was
initially raised, which the biopsy and immunohistochemistry results confirmed to
be a desmoid tumor. In immunohistochemistry, the positive presence of actin and
vimentin, desmin is rarely positive, while S100 and CD34 are negative, being
useful for the diagnosis of desmoid tumor[29 ].
On MRI, desmoid tumors are typically irregular masses, with a poorly defined
contour, hypointense, and isointense concerning the muscle in T1-weighted
sequences and with variable signal hyperintensity in T230-weighted sequences.
These findings are evidenced in [Figures 11A ], [11B ], [12A ] and [12B ].
Figure 11. In the topography of the left pectoral muscle, in its central and
medial aspects, at the level of the second to fifth intercostal
spaces, there is a heterogeneous solid-cystic nodular image, with
irregular thick walls and heterogeneous enhancement, measuring 9.4 x
7.2 x 5.0 cm, with rapid initial enhancement and persistent type
kinetic curve. This nodular image displays intimate contact with the
implant capsule (with its enhancement and displacing the implant
anteriorly) and also displays contiguity with the intercostal
muscles posteriorly (with its enhancement), attached to the
pulmonary pleura and pericardium in the respective intercostal
spaces and without enhancement of the adjacent costal arches and
cartilages.
Figure 12. In the superomedial quadrant of the left breast, 11 o’clock,
posterior third, close to the presternal region, there is nodular,
irregular, spiculated, heterogeneous enhancement, measuring 3.4 x
3.2 x 2.2 cm, 9.7 cm away from the nipple-areola complex and
invading the anterior half of the ipsilateral pectoral muscles, with
rapid initial enhancement and persistent type kinetic curve.
Diagnostic investigation through imaging tests such as magnetic resonance imaging
can facilitate the elucidation of so-called “unusual” complications in breast
implant surgeries. Given these possible changes, the patient must be informed in
advance about the inclusion of breast implants, as her decision may have future
implications, requiring new surgical interventions for treatment if
complications occur.
CONCLUSION
It is estimated that there are 50 million women with breast implants in the
world. The number of women undergoing breast augmentation with silicone implants
tends to increase and Brazil is one of the main countries in statistical
numbers. Based on this trend, the number of so-called “unusual” complications
becomes a diagnostic challenge for plastic surgeons and radiologists.
In the present study, a low incidence of unusual complications was found, with 12
cases out of 211 analyzed using breast MRI. This diagnostic method helps in the
early detection of these changes and provides greater safety for post-operative
monitoring, due to its high sensitivity and specificity, playing a central role
in therapeutic guidance.
Bibliographical Record
