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.

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: Desmoid tumor of the breast is very rare and locally aggressive but has no distant metastasis. Bilateral lesions are extremely rare, found in only 4% of patients. Two cases of bilateral desmoid tumor of the breast are reported. The clinical presentation, diagnosis, imaging, treatment, and follow-up outcomes of recurrence as well as a brief literature review are provided.
METHODS: Case 1 is a 31-year-old woman who presented with nipple retraction. An ultrasound revealed BIRAD V in both breasts. She underwent a bilateral excisional biopsy under ultrasound mark with the pathology result of extra-abdominal desmoid tumor in both breasts. The patient had a bilateral mastectomy with silicone implantation due to the involved margins by excision. She remained tumor free after 7-year follow-up. Case 2 is a 28-year-old woman who presented with a lump on her right breast that she had discovered ~2 months earlier. An ultrasound showed a spiculated mass in the right breast and some circumscribed hypoechoic masses in both breasts. A bilateral breast excision was done. The pathology result was an extra-abdominal desmoid tumor. She had recurrence on both sides and underwent a mastectomy and silicone implantation. The tumor has not recurred after 1-year follow-up.
CONCLUSIONS: Imaging cannot distinguish between benign breast lesions and malignancy. Pathology results are helpful in making a definitive diagnosis. Given that the desmoid tumor is locally aggressive, a local excision with clear margins is recommended. Chemotherapy and hormonal treatment are controversial.