Desmoid fibromatosis of the breast (also known as desmoid tumor of the breast) is a rare entity infrequently encountered by oncologists and surgeons caring for patients with breast disease. The current body of literature is highly reliant on case series and extrapolations from other sites of desmoid tumor-related disease. Much remains unclear regarding the pathological origins, natural history, and response to treatment of this condition. Traditional treatment strategies have centered on surgical resection, which may result in significantly disfiguring cosmetic and functional outcomes, frequent need for re-operation, and associated morbidity. There are limited data to support the superiority of upfront surgical resection when compared to medical therapy or watchful waiting strategies. Current treatment guidelines for desmoid tumors do not focus on the breast as a site of disease and are purposefully ambiguous due to the paucity of evidence available. We aim to review the literature concerning desmoid fibromatosis of the breast and propose an algorithm for current evidence-based management of this rare disease in the context of our experience with this pathology at a high-volume quaternary referral center.

Breast fibromatosis is a benign breast tumor of mesenchymal origin, accounting for 0.2% of breast tumors. This study reports two cases of breast fibromatosis highlighting its diagnostic, morphological, therapeutic and evolutionary features. In both cases, this tumor clinically and radiologically mimicked a cancer. Diagnostic confirmation was based on histological examination. Breast fibromatosis was characterized by local progression and a tendency to recurrence, hence the role of surgical excision with free surgical margins in our patients. The role of locoregional treatments (radiotherapy and cryotherapy) and medical treatments, in particular anti-estrogen therapy, is not clearly defined. In conclusion, breast fibromatosis must be known as it mimicks breast cancer and is characterized by a very high recurrence rate, without ever developing metastases.

Studies suggest that surgical breast augmentation with implants is a risk factor for breast desmoid tumors. The statistical strength of this correlation is unknown, as evidence is limited to anecdotal reports.
Patients with breast desmoid tumors and a history of breast implants seen at a single center between 2000 and 2021 were identified via radiology, breast, and sarcoma databases. The standardized incidence ratio (SIR) was calculated to assess the correlation between breast desmoid tumors and breast implants. The cases were pooled with published cases for analyses. Progression-free survival curves and hazard ratios were estimated using the Kaplan-Meier method and Cox proportional-hazards modeling.
Fourteen patients from one institution and 66 cases in the literature were identified. All patients were female, and the mean age was 38 years old (range 20-66). 63 patients (82%) underwent resection, 9 (12%) received chemotherapy, 3 (4%) received sorafenib, 11 (14%) received hormonal therapy, and 3 (4%) underwent active surveillance. After resection, the 2-year recurrence-free survival rate was 77% (95% CI 65%-89%). The recurrence risk was lower for resection with no residual tumor (R0) compared to microscopic (R1) or macroscopic (R2) residual tumor (HR: 0.15; 95% CI 0.02-0.8; p < 0.05). The SIR was 482 (95% CI 259-775) to 823 (95% CI 442-1322), suggesting a 482-823 times higher risk of developing a breast desmoid tumor after breast augmentation than the general population.
We present a nonrandom association between breast implants and desmoid tumors. Whether the tumors arise from the surgical trauma or the implant\'s biomaterial is unknown. When surgery is indicated, negative margins reduce the risk of recurrence.

We herein present a rare case of breast fibromatosis, the contrast-enhanced ultrasonography (CEUS) findings of which we believe have never been described. The high similarity between the clinical and imaging manifestations of breast cancer makes its differential diagnosis difficult. In this report, we describe the CEUS findings of a less common type of fibromatosis, discuss the potential value of CEUS to differentiate it from malignant breast lesions, and briefly review the literature.

Breast fibromatosis is a rare histologically benign tumor with local aggressive potential, and imaging and clinical findings of breast fibromatosis require attention. We retrospectively evaluated the images of 20 patients with histologically proven breast fibromatosis on mammography, magnetic resonance imaging (MRI), and ultrasonography. The lesions were assessed concerning the location, fascia involvement, imaging characteristics, and follow-up outcomes. Altogether, there were 22 lesions: 10 lesions involved the superficial fascia system including four lesions additionally involving the deep fascia and pectoralis major, and 12 lesions were inside the glandular parenchyma with two lesions originated from the prior surgery site. The detection rates of mammography, ultrasound, and MRI for breast fibromatosis were 33.3% (3/9), 90% (18/20), and 100% (3/3), respectively. We found that fascia involvement may be a characteristic of breast fibromatosis. The lesion located inside glandular parenchyma is prone to be underestimated, whereas combined MR with ultrasound is recommended for the diagnosis. The complete excision with negative margins is important for a good prognosis.

Fibromatosis of the breast is a rare condition that can be locally aggressive. The mainstay of treatment remains wide local excision, with varied adjuvant therapy as needed. The authors describe their experience in the treatment of a series of patients and propose the classification of primary and secondary breast fibromatosis. A single-institution retrospective analysis of patients treated for breast fibromatosis from 2003 to 2017 was completed. Demographic data, pertinent past medical history, and treatment modalities were reviewed. Primary breast fibromatosis was defined as arising in the absence of previous surgery or radiation therapy to the ipsilateral breast. Secondary breast fibromatosis was defined as arising in the setting of previous surgery or radiation therapy to the ipsilateral breast. A total of 16 patients were included with the median age 40 (28-64) years. The average size of the lesion was 6.37 cm (range of 1.5-15 cm). Mean follow-up time was 65 months. Surgical excision was completed in 14 patients, with two recurrences. There were no recurrences in patients with surgical margins >1 cm. Two patients were treated nonsurgically. There were seven patients with primary fibromatosis of the breast and nine patients with secondary fibromatosis of the breast. Fibromatosis of the breast is difficult to diagnose prior to surgical excision. We advocate for the multi-disciplinary treatment of this disease process with an aggressive surgical approach to achieve margins >1 cm.

Breast fibromatosis, also referred to as desmoid tumor or aggressive fibromatosis, is a very rare, locally aggressive disease that does not metastasize. Bilateral lesions are extremely rare and are found in only 4% of patients with breast fibromatosis. Tumor recurrence following surgery occurs in 18%-29% of patients, most often within the first 2 years after surgery. In this report, we discuss a case of breast fibromatosis, mimicking a breast carcinoma both clinically and radiologically, that presented clinically with dimpling of the skin of the left breast in a 31-year-old woman. The patient relapsed a few months after surgery, with a multicentric and bilateral disease.

Fibromatosis of the breast is a rare benign disease compromising <0.2% of all primary breast tumors. Although the chest wall is a common location, occurrences of implant-associated fibromatosis of the breast are extremely rare; only 33 cases have been reported. We present a case of a 42-year-old female who underwent breast augmentation with silicone breast implants, and 2 years later developed an aggressive implant-associated fibromatosis of the breast and chest wall. On imaging studies, the tumor mimicked breast carcinoma, and despite chemotherapy, the fibromatosis rapidly enlarged and was locally invasive requiring wide surgical excision. Unlike previously reported imaging findings, magnetic resonance imaging revealed an oval circumscribed mass with fringe-like internal architecture. We provide a review of the literature and discuss the imaging features of implant-associated fibromatosis of the breast.

BACKGROUND: Breast fibromatosis is a rare disease characterized by monoclonal fibroblast proliferation. It has no ability to metastasize but has a high local recurrence rate and often infiltrates surrounding tissues. Surgical treatment is the reference, but recently, new targeted therapies have emerged. We report an original case of a patient with breast fibromatosis who received exclusive medical treatment. Our aim was to analyze these treatments based on the clinical and radiological outcome, iatrogenic effects, and pharmacological action.
METHODS: We report the case of a 19-year-old woman who developed a desmoid-type fibromatosis of the lower inner quadrant of the right breast, measuring 50 × 25 mm (i.e., a volume of 27.4 cm3). Initial surgery was not possible because of potential esthetic and functional prejudice. Thus, she had an exclusive medical treatment including several lines: NSAIDs with tamoxifen and triptorelin, followed by sorafenib, then interferon α2b, and finally sunitinib. With tyrosine-kinase inhibitors (TKIs) (sunitinib), a significant partial response was observed (57% reduction of the maximal tumoral volume). For each treatment, we provided the clinical and radiological outcome in association with known pharmacological action.
CONCLUSIONS: TKI had been an interesting alternative option to initial surgery, providing at least a partial response and potentially allowing less mutilating surgery. However, no pharmacological mechanism can unequivocally explain TKI efficacy. In general, breast fibromatosis should be treated along with oncologist and interventional radiologists in a trans-disciplinary modality, thus offering an adapted treatment for this particular desmoid-type fibromatosis localization.

Breast fibromatosis is a rare entity responsible for 0.2% of all solid breast tumors. It has been associated with scars, pregnancy, implants, and familial adenomatous polyposis. We present an interesting case of breast fibromatosis in a 29 year old woman which encroached upon her saline implant and subsequently filled its cavity once the implant was removed. The patient was put on tamoxifen therapy and at 14 month follow-up there was a significant decrease in the size of the mass. Dynamic MRI images are offered for review and current treatment options are discussed.