Fibroadenomas are benign breast tumours characterized by an admixture of stromal and epithelial tissue. Breasts are made of lobules (milk producing glands) and ducts (tubes that carry the milk to the nipple). These are surrounded by glandular, fibrous and fatty tissues. Fibroadenomas develop from the lobules. The glandular tissue and ducts grow over the lobule to form a solid lump. Since both fibroadenomas, and breast lumps as a sign of breast cancer can appear similar, it is recommended to perform ultrasound analyses and possibly tissue sampling with subsequent histopathologic analysis in order to make a proper diagnosis. Unlike typical lumps from breast cancer, fibroadenomas are easy to move, with clearly defined edges.Fibroadenomas are sometimes called breast mice or a breast mouse owing to their high mobility in the breast. Signs and symptoms
Fibroadenomas are benign (not harmful in effect) tumours of the breast, most often present in women in their 20s and 30s. Clinically, fibroadenomas are usually solid breast lumps that are:
•	Painless•	Firm or rubbery•	Mobile•	Solitary-round with distinct, smooth borders
People who have a simple fibroadenoma have a slightly increased risk of developing malignant (harmful) breast cancer. Complex fibroadenomas may increase the risk of breast cancer.In the male breast, fibroepithelial tumors are very rare, and are mostly phyllodes tumors. Exceptionally rare case reports exist of fibroadenomas in the male breast, however these cases may be associated with antiandrogen treatment. Cause
The cause of fibroadenoma is unknown (idiopathic).
The procedure can be performed as an outpatient surgery using local anesthesia, and leaves substantially less scarring than open surgical procedures and no breast tissue deformation.The American Society of Breast Surgeons recommends the following criteria to establish a patient as a candidate for cryoablation of a fibroadenoma:
The lesion must be sonographically visible. The diagnosis of a fibroadenoma must be confirmed histologically. The lesion should be less than 4 cm in diameter. High Intensity Focused Ultrasound
High Intensity Focused Ultrasound (HIFU) is a newer technique for the treatment of malignant and benign tumors of the breast and has shown promising results in the form of complete radiological removal of tumors. An ultrasound beam is focused on a target in the breast and leads to tissue death and protein degradation by raising the temperature in that area. Currently, the use of radiation is recommended in some cases, but HIFU in particular is not part of treatment guidelines. Further research into the usefulness of HIFU, specifically in fibroadenoma, is required before more widespread use of the technique in fibroadenoma. Epidemiology
Of all breast tissue samples taken, fibroadenomas comprise about 50%, and this rate rises to 75% for tissue sample in women under the age of 20 years. Fibroadenomas are more frequent among women in higher socioeconomic classes and darker-skinned people. Body mass index and the number of full-term pregnancies were found to have a negative correlation with the risk of fibroadenomas. There are no known genetic factors that influence the rate of fibroadenomas.