Last updated date: 09-Jun-2023

Originally Written in English




Fibroadenomas are frequent benign (non-cancerous) breast tumors composed of glandular and stromal (connective) tissue. Fibroadenomas are most frequent in women in their twenties and thirties, although they can occur at any age. They tend to contract once a woman has menopause.


Fibroadenomas definition

A fibroadenoma is a painless, unilateral, benign (non-cancerous) breast tumor that is solid rather than fluid-filled. It is most frequent in women between the ages of 14 and 35, but it can occur at any age. Because fibroadenomas decrease after menopause, they are less prevalent in postmenopausal women. 

Because of their rapid motility, fibroadenomas are sometimes referred to as breast mice. Fibroadenomas are marble-like masses of epithelial and stromal tissues found beneath the surface of the breast. The size of these solid, rubbery lumps with uniform edges is frequently changeable.



Fibroadenoma usually develops in childhood. It is more prevalent in teenagers and less common in postmenopausal women. In the general population, the frequency of fibroadenoma declines with age and is most common in females under the age of 30. It is expected that 10% of the world's female population will develop fibroadenoma at some point in their lives.

Fibroadenomas account for around 50% of all breast biopsies, and this figure climbs to 75% for biopsies performed on women under the age of 20. Fibroadenomas are more common in women from higher socioeconomic strata and in people with a dark complexion. 8 The age of menarche, menopause, and hormone medication, including oral contraceptives, were found to have no effect on the risk of these lesions.

Body mass index and the number of full-term pregnancies, on the other hand, were shown to have a negative association with the incidence of fibroadenomas. Furthermore, high vitamin C consumption and cigarette smoking were found to be related to a lower incidence of fibroadenoma. 



The causes of fibroadenoma are unknown, however, experts believe that the lesion is caused by an increase in the sensitivity of breast tissue to the female reproductive hormone estrogen. Fibroadenoma often increases during pregnancy and shrinks after menopause. This lends credence to the hormonal etiology explanation. Females who use oral contraceptives before the age of 20 are more likely than the general population to develop fibroadenoma.



Fibroadenoma Pathophysiology


Fibroadenoma develops from stromal and epithelial connective tissue cells in the breast, which are both functional and mechanically significant. These tissues include estrogen and progesterone receptors. As a result of the increased synthesis of female reproductive hormones during pregnancy, fibroadenomas tend to grow. Breast connective tissues proliferate excessively as a result of hormone sensitivity.



A fibroadenoma is a well-circumscribed, non-encapsulated tumor with pushing boundaries that does not invade the surrounding breast parenchyma. They are distinguished by stromal and glandular cellular growth (benign breast ducts). The stroma-to-gland ratio remains essentially stable throughout the lesion.

The stroma is homogeneous and hypovascular, with spindle-shaped cells and bland oval to elongated nuclei. There is no evidence of stromal cell pleomorphism. The stroma may contain smooth muscle, cartilage, and bone. Although stromal mitosis is uncommon, it can be detected, particularly in younger women's fibroadenomas, and does not suggest malignancy. The stroma in elderly women might be hyalinized.

A fibroadenoma's glands are made up of the usual bi-cell layer seen in breast ducts. The inner glandular layer is made up of cells with cuboidal to columnar shapes and homogenous nuclei. An outer myoepithelial cell layer supports the inner cell layer. The myoepithelial layer remains intact across the whole lesion, indicating that the fibroadenoma is benign.

The epithelium can be involved in benign changes such as ductal hyperplasia, apocrine metaplasia, squamous metaplasia, cystic changes, and sclerosing adenosis. Calcifications in the glands are also possible. The epithelium may exhibit lactation alterations during pregnancy.

In fibroadenomas, there are two histological growth patterns: intracanalicular and pericanalicular. In the intracanalicular pattern, the stroma compresses and distorts the glands, resulting in cleft-like gaps. The stroma surrounds the glands without distorting them, and the glands retain their pericanalicular pattern of open lumens.


Symptoms of fibroadenoma

Symptoms of fibroadenoma

The most important determinant in the occurrence of fibroadenoma is age. As a result, while gathering a medical history, the most crucial aspect to consider is age.

It is also important to have a family history of breast cancer. Female patients with first-degree relatives who have breast cancer should be examined and evaluated for malignant signs more closely than patients who do not have this family history. Fibroadenoma is most usually found in the breast's upper outer quadrant. Physically, it possesses the following characteristics:

  • Non-tender or painless
  • Mobile
  • Solitary
  • Rapidly growing solid lump with rubbery consistency and regular borders.


Multiple Fibroadenomas

Two to four fibroadenomas in a single breast are seen in 10% to 16% of people with multiple fibroadenomas, which may appear initially or be detected over time. In contrast to women who have a single fibroadenoma, the majority of patients with multiple fibroadenomas have a significant family history of these tumors. A probable link between numerous fibroadenomas and oral contraceptives has been hypothesized but has yet to be proven.


Giant and Juvenile Fibroadenomas

Giant fibroadenomas are described as fibroadenomas greater than 5 cm in diameter (about 4% of all fibroadenomas); however, this nomenclature is not widely recognized. Giant fibroadenomas are most commonly found in pregnant or breastfeeding women. When it is discovered in an adolescent female, the label juvenile fibroadenoma is more accurate.

These lesions, which account for 0.5 to 2% of all fibroadenomas in young women, are quickly developing masses that cause asymmetry of the breast, distortion of the overlying skin, and straining of the nipple. They appear to be more cellular and have fewer lobular components than basic fibroadenomas. Giant fibroadenomas, on the other hand, are benign tumors that do not progress to cancer.



Fibroadenoma Diagnosis

The following imaging modalities are used to diagnose fibroadenomas after a comprehensive history and physical examination.

Diagnostic Mammogram

Breast sonography is frequently used to diagnose fibroadenomas. A round or oval solid mass with a smooth contour, faint internal echoes in a uniform distribution, and intermediate acoustic attenuation are sonographic parameters that support the diagnosis of a fibroadenoma. This imaging approach is quite helpful in distinguishing between solid and cystic lesions.

Attempts to connect the sonographic characteristics of solid masses consistent with fibroadenomas with pathologic results, however, were unsuccessful. The sonographic criteria for fibroadenomas and breast cancer overlap slightly, and roughly 25% of fibroadenomas have irregular borders, which may indicate that the lesions are malignant. 29 In another research, only 82 percent of biopsy-proven fibroadenomas were visible by sonography.

Mammographic characteristics of fibroadenomas range from a well-circumscribed discrete oval mass of breast glandular tissue that is hypodense or isodense to a mass with massive lobulation or partially concealed edges. Involuting fibroadenomas in older individuals, usually postmenopausal, may include calcification, giving the distinctive, coarse popcorn calcification look.



Fine needle aspiration (FNA) is a preferred procedure for evaluating breast masses. Clusters of spindle cells without inflammatory or fat cells are found in 96% of all fibroadenomas; aggregates of cells with a papillary configuration resembling elk antler (antler horn clusters) are found in 93% of all cases; uniform cells with well-defined cytoplasm lying in rows and columns (honeycomb sheets) are found in 95% of all fibroadenomas.

When combined with a clinical diagnosis of fibroadenoma, FNA can boost sensitivity to 86 percent with a specificity of 76 percent, but for breast cancer, FNA is 96 percent sensitive and 98 percent specific. As a result, while aspiration cytology might mix fibroadenomas with other benign breast tumors, misdiagnosis of a malignant process is uncommon.

The total diagnostic effectiveness of these three modalities, namely physical breast examination, imaging, and cytology, is around 70% to 80%, however, they give a 95% correct difference between a benign and a malignant tumor. A one- to three-year follow-up period after fibroadenoma is detected and breast cancer is ruled out using the three modalities can improve the accuracy of the diagnosis.


Breast Ultrasound  

Ultrasound (US) is a technique that employs sound waves to identify the characteristics of fibroadenomas in women under the age of 35. The US readily distinguishes between solid and cystic masses. A fibroadenoma is commonly diagnosed as a well-circumscribed, round to ovoid, or macrolobulated mass with relatively consistent hypoechogenicity in the United States. If necessary, a core needle biopsy can be used to accomplish a minimally invasive biopsy.



Fibroadenoma Management

Fibroadenomas, in the vast majority of cases, do not require treatment. They will eventually diminish and vanish, but if they are huge and squeezing other breast tissues, they should be removed. Many females choose out of surgery since the lesions are non-cancerous and provide no long-term risk of malignancy. The form of a breast is also distorted by surgery.



Fibroadenoma Surgery

If the fibroadenoma is large and continues to grow, doctors may opt to remove it. Rapid growth, a size larger than 2 cm, and patient desire are all indications for surgical intervention.

There are 2 surgical procedures used to remove a fibroadenoma:

  1. Lumpectomy or excisional biopsy: In this procedure, the surgeon removes the fibroadenoma and sends it to the laboratory for further evaluation.
  2. Cryoablation: Cryoprobes are used by surgeons to freeze and destroy the cellular structure of fibroadenoma. To confirm the fibroadenoma, a core needle biopsy must be done prior to cryoablation.


The chance of missing breast cancer in women under the age of 25 with fibroadenomas identified by physical examination, sonography, and FNA ranges from one in 229 to one in 700. This risk is still quite low in women under the age of 35. As a result, it has been suggested that young patients be monitored with periodic clinical examinations, and lesions be removed in women over the age of 35.

Other researchers proposed that the threshold age be 25 years. Complete excision is the best treatment for numerous fibroadenomas. However, if all of the fibroadenomas are removed by a single incision, this method may result in undesired scarring or significant ductal damage.

Because giant fibroadenomas diminish after breastfeeding, their treatment should be postponed until the patient's hormonal situation returns to normal and a smaller excision may be performed. Because of their great size, excising juvenile fibroadenomas can be exceedingly disfiguring; nevertheless, no recurrences have been observed following full excision, and normal and symmetrical breast growth can be expected.


Vacuum-assisted (VAC/VAB) excision biopsy

To remove the fibroadenoma, you may be offered a vacuum-aided excision biopsy. This is a method of removing tiny fibroadenomas under local anesthesia rather than undergoing a general anesthesia procedure.

A tiny incision is made in the skin after local anesthetic injection. This is passed through using a hollow probe attached to a vacuum apparatus. Using an ultrasound as a guide, the vacuum draws the fibroadenoma through the probe and into a collecting chamber. The biopsy equipment is utilized in this manner until the fibroadenoma has been completely excised. This might suggest that surgery is not necessary.

The tissue is removed and transported to a laboratory to be studied under a microscope. For a few days following the treatment, there may be some bruising and soreness. The removal of a fibroadenoma normally has little effect on the form of the breast, however, there may be a minor dimple in the breast where it was removed.


Differential Diagnosis

A fibroadenoma can be confused with:

  • Breast cyst
  • Breast carcinoma
  • Phyllodes tumor
  • Breast lymphoma
  • Metastasis to the breast from another primary site

The prognosis of fibroadenoma is favorable since it is a benign tumor that, in the majority of instances, diminishes in size over time.



Any study of the links between fibroadenomas and breast cancer must answer two key questions: if a fibroadenoma is a risk factor for breast cancer, and whether breast cancer may develop from the epithelial component of a fibroadenoma. The first problem was initially investigated in multiple retrospective studies, which revealed a 1.3 to 2.1 higher risk of breast cancer in women with fibroadenomas when compared to the general population.

The higher risk persisted and did not diminish with time. A more recent study adopted the term "complex fibroadenoma" to describe the probable relationship between the histologic characteristics of fibroadenomas and the risk of later breast cancer. This phrase refers to fibroadenomas that are greater than 3 mm in diameter, or have components of sclerosing adenosis, epithelial calcifications, or papillary apocrine metaplasia, and are related to a 3.1 increased risk of breast cancer.

Proliferative alterations in the parenchyma close to the fibroadenoma were linked to a 3.88-fold increase in risk. When compared to control women with a family history of breast cancer but no fibroadenoma, the relative risk for women with a familial history of breast cancer and complicated fibroadenoma was 3.72. Women with noncomplex fibroadenomas and no family history of breast cancer were not at a higher risk of developing breast cancer in these trials.

Malignant changes in the epithelial components of fibroadenomas are thought to be uncommon. The incidence of a carcinoma developing within a fibroadenoma has been found to range between 0.002 and 0.0125 percent. About half of these tumors were lobular carcinoma in situ (LCIS), 20% were infiltrating lobular carcinoma, 20% were ductal carcinoma in situ (DCIS), and 10% were infiltrating ductal carcinoma.

The clinical, sonographic, and mammographic findings are often identical to those of benign fibroadenomas, and malignant alterations are frequently detected only after the fibroadenoma is removed.


Follow-Up Care

Most women will not require anything more than basic screening tests. They will continue to have any breast changes evaluated by a doctor.

When compared to women who do not have fibroadenomas, having a simple fibroadenoma may increase your risk of breast cancer. However, if you have a complicated fibroadenoma, you could be at a slightly increased risk of developing breast cancer later in life. Unless you have other factors that increase your chances of developing breast cancer, such as close family members who have the illness, your chances are still slim.

In any case, maintain your monthly checkups and ask your doctor which screening tests you require and when.



The majority of breast lesions in young women are discovered during an accidental breast exam, which is performed by either the patient or a healthcare practitioner. Even though fibroadenomas are benign tumors, it is often necessary to establish histology. Nurse practitioners, in particular, should never presume that all hard, rubbery lesions are benign. If in doubt, have a biopsy performed by a radiologist or surgeon. Missing a cancerous breast tumor in a young female can have serious consequences.