Bilateral desmoid tumor of the breast: case seriesand literature review

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. CASE REPORTS 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. CONCLUSION 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.