A desmoid tumor (also known as aggressive fibromatosis) is a rare benign lesion that
is characterized by fibroblastic proliferation from the connective tissue of the muscle
and its overlying aponeurosis of fascia. "Aggressive fibromatosis" is the term used
to describe a marked increased in cellularity and aggressive local behavior [[1]]. Desmoid tumors are characterized by a clinical course that ranges from locally
inert to aggressive and destructive forms [[2]]. Although the mechanisms that affect the development, regulation, and growth of
desmoid tumors are currently unknown, numerous factors, such as trauma history, hereditary
background (e.g., familial adenomatous polyposis), and the hormonal environment are
strongly associated with the development of desmoid tumors [[1]
[3]]. Desmoid tumors account for 0.03% of all neoplasms and 0.2% of all breast tumors.
There are few case reports describing implant-associated breast desmoid tumors in
the literature [[4]], and no studies associated with breast implants have been reported in Korea. We
report here a case of a desmoid tumor that developed following augmentation mammoplasty
and describe our experience of treating this case.
A 34-year-old woman was referred to our hospital in February 2012 due to a painful
mass in the upper part of her left breast that was increasing in size. She had undergone
augmentation mammoplasty with silicone implants at a local clinic in January 2010,
but the implant had been changed because capsular contracture had developed in August
2010. Two years after the implant was changed, this patient's symptoms, including
pain and asymmetry, became progressively more aggravated. She visited another local
clinic and the implant was scheduled to be changed again to relieve the symptoms of
capsular contracture in February 2012. During this surgery, a palpable mass was incidentally
found under the pectoralis muscle of her left breast, and she was referred to our
hospital.
Preoperative magnetic resonance imaging (MRI) revealed a well-defined solid submuscular
mass with low to intermediate signal intensity on T1 imaging and high signal intensity
on T2 imaging, demonstrating a size of 6.4 cm×2.6 cm×5.8 cm ([Fig. 1]). Tumor excision and capsulectomy were subsequently performed. The diagnosis of
frozen biopsy was benign mesenchymal tumor, type deferred. Based on frozen biopsy
and perioperative findings, we decided to excise as much of the tumor as possible
rather than excise widely including normal tissue for a clear resection margin. On
gross examination, the tumor was dense and rubbery, and the cut surface was relatively
homogeneous demonstrating a fine network of grayish-yellow bundles ([Fig. 2]). After the operation, the final diagnosis of desmoid tumor (fibromatosis) with
an indeterminate resection margin was confirmed pathologically ([Fig. 3]). The patient refused the option of a reexcision procedure and MRI follow-up. She
wanted another augmentation mammoplasty, which we refused for oncologic safety, and
she was then lost to follow-up.
Fig. 1
A well-defined soft tissue mass (green arrow) measuring 6.4 cm×2.6 cm×5.8 cm in the
submuscular area of the left anterior chest is shown. (A), (B) T1 imaging, and (C)
T2 imaging.
Fig. 2
Fragmented pathological specimen with grayish-yellow, solid, glistening, and fibrotic
cut surface.
Fig. 3
Microscopic image of the pathological specimen. Clusters of spindle-shaped cells and
fibroblasts are shown (H&E, ×100).
The natural progression of desmoid tumors remains unpredictable and enigmatic. While
this disease rapidly and aggressively progresses in some cases, in other cases, desmoid
tumors tend to demonstrate slow and locally invasive growth. Partial regression as
well as periods of rapid growth have been reported. However, unlike malignant tumors,
these locally invasive tumors do not metastasize. The survival rates are, therefore,
excellent, although recurrence and complication rates are high for this disease [[5]].
Extra-abdominal desmoid tumors are always confined to the connective tissue of the
muscle and its overlying aponeurosis of fascia. Thus, when these lesions are found
in association with breast implants, the fibrous capsule that forms around the implant
is typically implicated as a possible source. Desmoid tumors tend to be hard and firm
in consistency, demonstrate a gritty sensation when cut, and have a cross-sectional
surface that is glistening, white, and coarsely trabeculated. Histologically, a spectrum
of microscopic patterns is often observed, including small clusters or sheets of spindle-shaped
cells and fibroblasts, which demonstrate abundant eosinophilic cytoplasm and are separated
by large quantities of collagen. Mitotic figures and notable nuclear atypia are rare,
although they may be focally abundant with small nuclei that lack pleomorphisms [[3]]. These characteristic features explain why fine-needle aspiration of these lesions
often fails to confirm a diagnosis. Desmoid tumors are typically isointense on T1-weighted
imaging and demonstrate low to high signal intensity on T2-weighted imaging. MRI analyses
in conjunction with the intravenous administration of a contrast agent typically demonstrate
heterogeneous gradual enhancement that is believed to reflect a significant amount
of collagenous tissue in the tumor. MRI can also play an invaluable role in preoperative
diagnosis and planning. The excision of a desmoid tumor with negative margins plays
a key role in management and is among the principal therapeutic modalities that are
currently available. The treatment aim is usually curative, especially for extra-abdominal,
localized, small-volume cases. Local recurrence following surgery can vary considerably
depending on the surgical margin status. Radiotherapy, hormonal therapy, and chemotherapy
can also be applied, but there are currently no evidence-based pharmacological or
radiotherapeutic treatment protocols [[4]].
Only 24 cases of implant-associated breast desmoid tumors have been described in the
literature. Among these, only eight cases developed following the implantation of
saline implants. The remaining 16 cases developed in association with silicone implants
[[4]]. These lesions may develop after the implantation of either saline or silicone
implants, but they develop more commonly when silicone implants are used. When a breast
mass has developed after implant insertion, physicians must consider desmoid tumor
and anaplastic large cell lymphoma in the diagnosis, although the incidence is low.
This article is the first report describing an implant-associated breast desmoid tumor
in Korea. Although there is no evidence to suggest that breast augmentation with either
saline or silicone implants is associated with an increased risk of developing desmoid
tumors, appropriate vigilance and follow-up examinations are necessary to ensure a
timely diagnosis, especially in women who develop capsular contracture following breast
augmentation.
