Fibroadenoma
Encyclopedia
Fibroadenomas of the breast
Breast
The breast is the upper ventral region of the torso of a primate, in left and right sides, which in a female contains the mammary gland that secretes milk used to feed infants.Both men and women develop breasts from the same embryological tissues...

, are lumps composed of fibrous and glandular tissue. Because breast cancer
Breast cancer
Breast cancer is cancer originating from breast tissue, most commonly from the inner lining of milk ducts or the lobules that supply the ducts with milk. Cancers originating from ducts are known as ductal carcinomas; those originating from lobules are known as lobular carcinomas...

 can also appear as a lump, doctors may recommend a tissue sample (biopsy
Biopsy
A biopsy is a medical test involving sampling of cells or tissues for examination. It is the medical removal of tissue from a living subject to determine the presence or extent of a disease. The tissue is generally examined under a microscope by a pathologist, and can also be analyzed chemically...

) to rule out cancer in older patients. 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

The typical case is the presence of a painless, firm, solitary, mobile, slowly growing lump
Breast lump
Breast lump is a localized swelling that feels different from the surrounding breast tissue. It is a symptom/sign for a variety of conditions. As approximately 10% of breast lumps ultimately lead to a diagnosis of breast cancer, it is important for women with a breast lump to receive appropriate...

 in the breast of a woman of childbearing years.

In the male breast, fibroepithelial tumors are very rare, and are mostly phyllodes tumor
Phyllodes tumor
Phyllodes tumors , also cystosarcoma phyllodes, cystosarcoma phylloides and phylloides tumor, are typically large, fast growing masses that form from the periductal stromal cells of the breast...

s. Exceptionally rare case reports exist of fibroadenomas in the male breast, however these cases may be associated with antiandrogen
Antiandrogen
Antiandrogens, or androgen antagonists, first discovered in the 1960s, prevent androgens from expressing their biological effects on responsive tissues. Antiandrogens alter the androgen pathway by blocking the appropriate receptors, competing for binding sites on the cell's surface, or affecting...

 treatment.

Diagnosis

A fibroadenoma is usually diagnosed through clinical examination, ultrasound
Medical ultrasonography
Diagnostic sonography is an ultrasound-based diagnostic imaging technique used for visualizing subcutaneous body structures including tendons, muscles, joints, vessels and internal organs for possible pathology or lesions...

 or mammography
Mammography
Mammography is the process of using low-energy-X-rays to examine the human breast and is used as a diagnostic and a screening tool....

, and often a needle biopsy sample of the lump.

Etiology and epidemiology

Fibroadenomas arise in the terminal duct lobular unit of the breast
Breast
The breast is the upper ventral region of the torso of a primate, in left and right sides, which in a female contains the mammary gland that secretes milk used to feed infants.Both men and women develop breasts from the same embryological tissues...

. They are the most common breast tumor in adolescent women. They also occur in a small number of post-menopausal
Menopause
Menopause is a term used to describe the permanent cessation of the primary functions of the human ovaries: the ripening and release of ova and the release of hormones that cause both the creation of the uterine lining and the subsequent shedding of the uterine lining...

 women. Their incidence declines with increasing age, and, in general, they appear before the age of thirty years. Fibroadenomas are partially hormone-dependent and frequently regress after menopause. They are hypovascular compared to typical (especially malignant) neoplasms.

Higher intake of fruits and vegetables, higher number of live births, 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 staining on DiffQuick staining. Foam cells and apocrine
Apocrine
Apocrine is a term used to classify exocrine glands in the study of histology. Cells which are classified as apocrine bud their secretions off through the plasma membrane producing membrane-bound vesicles in the lumen. This method is also called decapitation secretion...

 cells may also be seen, although these are less diagnostic features. The gallery images below demonstrate these features.

Macroscopic

Approximately ninety percent of fibroadenomas are less than three centimetres in diameter. The vast majority of the remaining ten percent that are four centimetres or larger occur mostly in women under twenty years of age. 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) got an incomplete capsule.

Microscopic

The proliferation forms duct-like spaces. These are surrounded by fibroblastic stroma. The proliferating epithelium is of normal appearance. Fibroadenomas may be sub-classified into two types, intracanalicular and pericanalicular, depending on the relative amounts of epithelial and stromal tissue present. There is also a mixed type, in which both forms coexist simultaneously. Intracanalicular fibroadenomas show predominant stromal proliferation that compresses the ducts, which are irregular and reduced to slits. Pericanalicular fibroadenomas show fibrous stromal proliferation around the ductal spaces that allows the duct spaces remain round or oval. The gallery image below demonstrates both morphological subtypes.

Treatment

Most fibroadenomas are left in situ and monitored by a doctor, or the patient in question. Some are treated by surgical excision. They are removed with a small margin of normal breast tissue if the preoperative clinical investigations are suggestive of the diagnosis. A small amount of normal tissue must be removed in case the lesion turns out to be a phyllodes tumour on microscopic examination.

Because needle biopsy is often a reliable diagnostic investigation, some doctors may decide not to operate to remove the lesion, and instead opt for clinical follow-up to serially observe the lesion over time using clinical examination and mammography
Mammography
Mammography is the process of using low-energy-X-rays to examine the human breast and is used as a diagnostic and a screening tool....

 to determine the rate of growth, if any, of the lesion. A growth rate of less than sixteen percent per month in women under fifty years of age, and a growth rate of less than thirteen percent per month in women over fifty years of age have been published as safe growth rates for continued non-operative treatment and clinical observation.

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

There are also natural treatments being touted to diminish fibroadenomas, such as Fibrosolve, but no definite studies have been made as to prove their effectiveness.

Cryoablation Treatment

The FDA has approved cryoablation
Cryoablation
Cryoablation is a process that uses extreme cold to remove tissue .Cryoablation is used in a variety of clinical applications using hollow needles through which cooled, thermally conductive, fluids are circulated...

 (the use of extreme cold to destroy tissue) of a fibroadenoma as a safe, effective and minimally-invasive alternative to open surgical removal. In the procedure, 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 in an office setting with local anesthesia only, and leaves substantially less scarring than open surgical procedures.

The American Society of Breast Surgeons
The American Society of Breast Surgeons
The American Society of Breast Surgeons is a professional medical society whose active members are general surgeons who dedicate all or part of their practices to the treatment of breast disease.-Demographics:...

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 fibroadenoma must be confirmed histologically.
  3. Lesions should be less than 4 cm in diameter.

Video on Fibroadenoma

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