Fibroadenoma Breast

          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

• Found in either one or both breasts

Cause

     The cause of fibroadenoma is unknown (idiopathic). A connection between fibroadenomas and reproductive hormones has been suggested which may explain why they present themselves during reproductive years, increase in size during pregnancy, and regress post-menopause.

Higher intake of fruits and vegetables, higher number of live births, lower use of oral contraceptives and moderate exercise are associated with lower frequency of fibroadenomas.

Cytology

The diagnostic findings on needle biopsy consist of abundant stromal cells, which appear as bare bipolar nuclei, throughout the aspirate; sheets of fairly uniform-size epithelial cells that are typically arranged in either an antler-like pattern or a honeycomb pattern. These epithelial sheets tend to show typical metachromatic blue on Diff-Quik staining. Foam cells and apocrine cells may also be seen, although these are less diagnostic features. The gallery images below demonstrate these features..

Macroscopic

Approximately 90% of fibroadenomas are less than 3 cm in diameter. However, these tumors have the potential to grow reaching a remarkable size, particularly in young individuals. The tumor is round or ovoid, elastic, and nodular, and has a smooth surface. The cut surface usually appears homogenous and firm, and is grey-white or tan in colour. The pericanalicular type (hard) has a whorly appearance with a complete capsule, while the intracanalicular type (soft) has an incomplete capsule.

Fibroadenoma of the breast is a benign tumor composed of a biphasic proliferation of both stromal and epithelial components that can be arranged in two growth patterns: pericanalicular (stromal proliferation around epithelial structures) and intracanalicular (stromal proliferation compressing the epithelial structures into clefts).

These tumors characteristically display hypovascular stroma compared to malignant neoplasms. Furthermore, the epithelial proliferation appears in a single terminal ductal unit and describes duct-like spaces surrounded by a fibroblastic stroma. The basement membrane is intact.

Treatment

Fibroadenomas can be expected to shrink naturally and so, most are simply monitored. Monitoring fibroadenomas involves regular check-ups to make sure that the breast mass is not growing and is not potentially cancerous. Check-ups involve physical examinations performed every 3–6 months and optional diagnostic imaging performed every 6–12 months for 1–2 years. Generally, surgery is only recommended if the fibroadenoma gets larger or causes increased symptoms. They are removed with a small margin of normal breast tissue if the preoperative clinical investigations are suggestive of the necessity of this procedure. A small amount of normal tissue must be removed in case the lesion turns out to be a phyllodes tumour on microscopic examination.

Some fibroadenomas respond to treatment with ormeloxifene.

Fibroadenomas have not been shown to recur following complete excision or transform into phyllodes tumours following partial or incomplete excision.

Non-invasive Surgical Interventions

There are several non-invasive options for the treatment of fibroadenomas, including percutaneous radiofrequency ablation (RFA), cryoablation, and percutaneous microwave ablation. With the use of advanced medical imaging, these procedures do not require invasive surgery and have the potential for enhanced cosmetic results compared with conventional surgery.

Cryoablation

The FDA approved cryoablation of a fibroadenoma as a safe, effective, and minimally-invasive alternative to open surgical removal in 2001. During cryoablation, ultrasound imaging is used to guide a probe into the mass of breast tissue. Extremely cold temperatures are then used to destroy the abnormal cells, and over time the cells are reabsorbed into the body. 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:

1.       The lesion must be sonographically visible.

2.       The diagnosis of a fibroadenoma must be confirmed histologically.

3.       The lesion should be less than 4 cm in diameter.

High Intensity Focused Ultrasound

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. The rate of occurrence of fibroadenomas in women have been reported in literature to range from 7% to 13%.

A fibroadenoma is a very common benign (not cancer) breast condition. The most common symptom is a lump in the breast which usually moves when you touch it.

Fibroadenomas often develop during puberty so are mostly found in young women, but they can occur in women of any age. Men can also get fibroadenomas, but this is very rare.   

Symptoms of fibroadenoma

A fibroadenoma is usually felt as a lump in the breast which has a rubbery texture, is smooth to the touch and moves easily under the skin.

Fibroadenomas are usually painless, but sometimes they may feel tender or even painful, particularly just before a period.

Types of fibroadenoma

1.     Simple fibroadenoma

Most fibroadenomas are about 1–3cm in size and are called simple fibroadenomas. When looked at under a microscope, simple fibroadenomas will look the same all over. Simple fibroadenomas don’t increase the risk of developing breast cancer in the future.

2.     Complex fibroadenoma

Some fibroadenomas are called complex fibroadenomas. When these are looked at under a microscope, some of the cells have different features.

Having a complex fibroadenoma can very slightly increase the risk of developing breast cancer in the future.

3.     Giant or juvenile fibroadenoma

Occasionally, a fibroadenoma can grow to more than 5cm and may be called a giant fibroadenoma. Those found in teenage girls may be called juvenile fibroadenomas.

Causes

It’s not known what causes a fibroadenoma. It’s thought that it probably occurs because of increased sensitivity to the hormone oestrogen.

Breasts are made up of lobules (milk-producing glands) and ducts (tubes that carry milk to the nipple). These are surrounded by glandular, fibrous and fatty tissue.

Fibroadenomas develop from a lobule. The glandular tissue and ducts grow over the lobule and form a solid lump.

Diagnosis

If you find a breast lump, see your GP (local doctor). They’re likely to refer you to a breast clinic where you’ll be seen by specialist doctors or nurses.

At the breast clinic you’ll have various investigations, known as ‘triple assessment’, to help make a definite diagnosis. This assessment consists of:

•        a breast examination

•        ultrasound scan (uses high frequency sound waves to produce an image) and/or a mammogram (breast x-ray)

•        a core biopsy and/or a fine needle aspiration (FNA).

Fibroadenomas are often easier to identify in younger women. If you’re in your early 20s or younger, your fibroadenoma may be diagnosed with a breast examination and ultrasound only. However, if there’s any uncertainty about the diagnosis, a core biopsy or FNA will be done.

If you’re under 40, you’re more likely to have an ultrasound than a mammogram. Younger women’s breast tissue can be dense which can make the x-ray image less clear so normal changes or benign breast conditions can be harder to identify. However, for some women under 40, mammograms may still be needed to complete the assessment.

Surgery

Sometimes an operation called an excision biopsy is needed to remove a fibroadenoma if it’s a large, complex or juvenile fibroadenoma. You can also ask to have a fibroadenoma removed.

This may be done using a local or general anaesthetic.

Your surgeon may use dissolvable stitches placed under the skin which won’t need to be removed. However, if a non-dissolvable type is used, they will need to be taken out a few days after surgery. You’ll be given information about this and about looking after the wound before you leave the hospital.

Vacuum assisted excision biopsy

You may be offered a vacuum assisted excision biopsy to remove the fibroadenoma. This is a way of removing small fibroadenomas under local anaesthetic, without having surgery.

After an injection of local anaesthetic, a small cut is made in the skin. A hollow probe connected to a vacuum device is placed through this. Using an ultrasound or mammogram as a guide, the fibroadenoma is sucked through the probe by the vacuum into a collecting chamber. The biopsy device is used in this way until all of the fibroadenoma has been removed. This may mean that an operation under a general anaesthetic can be avoided. The tissue removed is sent to a laboratory and examined under a microscope. This procedure can cause some bruising and pain for a few days afterwards.