Fibroadenoma

Overview
Fibroadenoma of the breast is a benign tumor characterized by proliferation of both glandular and stromal elements.

Pathology
Depending on the amount and the relationship between these two components, there are two main histological features: intracanalicular and pericanalicular. Often, both types are found in the same tumor. Intracanalicular fibroadenoma: stromal proliferation predominates and compresses the ducts, which are irregular, reduced to slits. Pericanalicular fibroadenoma: fibrous stroma proliferates around the ductal spaces, so that they remain round or oval, on cross section. The basement membrane is intact. 1

Macroscopically
The tumor is round, elastic, nodular, and encapsulated (well circumscribed); on cut surface it is grey-white.

Microscopically
The epithelial proliferation describes duct-like spaces surrounded by a fibroblastic stroma. The proliferated epithelium is typical.

Diagnosis
A fibroadenoma is usually diagnosed through clinical examination, ultrasound or mammography, and often a needle biopsy sample of the lump.

Most often it appears before the age of 30 years, as a result of estrogenic hormonal excess. It is common in teenagers and those taking artificial hormones. A fibroadenoma is not commonly associated with fibrocystic breast disease and has no known links to cancer. Usually the tumor is solitary, multiple tumors being rare. The tumor is mobile to adjacent structures: skin, muscle, and lymph nodes. It is commonly found immediately adjacent to the areola, though rarely directly behind the nipple. The tumours are slightly more common on the left breast than on the right, possibly for reasons associated with blood flow. Some malignant breast tumors can be easily mistaken for a fibroadenoma, so it is important for them to be diagnosed by a doctor.

Treatment
A fibroadenoma is a very benign tumor and is usually left untreated. A small tumor will often dissipate within several months, though larger ones may persist for a prolonged period of time. A tumor may be surgically removed, though this is usually only done in situations where it is unusually large or painful. No medications are used for the treatment of fibroadenoma.