Fibroadenoma overview

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

# Classification
Fibroadenoma may be classified according to microscopic histopathological analysis into four subtypes, which include juvenile fibroadenoma, complex fibroadenoma, myxoid fibroadenoma, and cellular fibroadenoma.

# Pathophysiology
Fibroadenoma is a common benign tumor of the breast. Fibroadenoma arises from connective tissue cells, which are cells that are normally involved in the functional and mechanical support of the surrounding tissues. Fibroadenoma demonstrate estrogen and progesterone sensitivity and may grow during pregnancy. The mediator complex subunit 12 (MED12) gene is the most common gene involved in the pathogenesis of fibroadenoma. On gross pathology, a rubbery, tan colored, and lobulated mass is a characteristic finding of fibroadenoma. On microscopic pathology, charectersitic findings of fibroadenoma include a biphasic proliferation of both stromal and epithelial components that can be arranged in two growth patterns; a pericanalicular growth pattern and an intracanalicular growth pattern.

# Causes
There are no known direct causes for fibroadenoma.  Common risk factors for fibroadenoma can be found here.

# Differentiating Fibroadenoma from other Diseases
Fibroadenoma must be differentiated from other diseases that cause a similar clinical presentation, such as phyllodes tumor, hamartoma, and adenomyoepithelioma.

# Epidemiology and Demographics
Fibroadenoma is the most common breast mass among adolescent women in the United States. There are no definite data regarding the exact incidence of fibroadenoma among the US general population. Fibroadenoma commonly affects individuals younger than 30 years of age. Females are more commonly affected with fibroadenoma than males. Fibroadenoma usually affects individuals of the African American race. Caucasian individuals are less likely to develop fibroadenoma.

# Risk Factors
Common risk factors in the development of fibroadenoma are obesity, estrogen replacement therapy, and nulliparity.

# Screening
According to the the U.S. Preventive Service Task Force (USPSTF), there is insufficient evidence to recommend routine screening for fibroadenoma.

# Natural History, Complications and Prognosis
Most patients with fibroadenoma are asymptomatic. If left untreated, patients with fibroadenoma may progress to develop a painless, mobile, and well-circumscribe breast lump. Fibroadenoma is a benign tumor that rarely develops any complications. Fibroadenomas commonly enlarge during pregnancy and involute after the age of menopause. The prognosis is generally excellent, and the 5-year survival rate of patients with fibroadenoma is almost equal to the normal population.

# Diagnosis

## History and Symptoms
The majority of patients with fibroadenoma are asymptomatic. The hallmark of fibroadenoma is the presence of a painless, firm, solitary, mobile, slowly growing lump in the breast.

## Physical Examination
Patients with fibroadenoma usually appear averagely built and well nourished. Physical examination of patients with fibroadenoma is usually remarkable for a painless, firm, solitary, well-circumscribed, and mobile breast mass.

## CT Scan
CT scan may be helpful in the diagnosis of fibroadenoma. Findings on CT scan suggestive of fibroadenoma include an oval mass with well defined borders, lobulated appearance, and localized calcification.

## MRI
MRI may be helpful in the diagnosis of fibroadenoma. On a T1 weighted brain MRI image, fibroadenoma is characterized by a well-defined, isointense mass located at the upper-outer quadrant of the breast.

## Echocardiography or Ultrasound
Ultrasound may be helpful in the diagnosis of fibroadenoma. Findings on ultrasound suggestive of fibrodenoma include a well-circumscribed, round to ovoid, macrolobulated mass that is generally uniformly hypoechogenic.

## Other Imaging Findings
Breast mammogram may be helpful in the diagnosis of fibroadenoma. On breast mammogram, fibroadenoma is characterized by a well circumscribed, discrete, oval mass that is isodense to breast glandular tissue. The mass may contain coarse, popcorn calcification.

## Other Diagnostic Studies
The definitive diagnosis of fibroadenoma is confirmed by an ultrasound guided biopsy. Characteristic findings for fibroadenoma on microscopic histopathological analysis can be found here.

# Treatment

## Surgery
The majority of cases of fibroadenoma are self-limited and only require close follow-up. The feasibility of surgery depends on the age of the patient at the time of diagnosis. Surgery is the mainstay of treatment for fibroadenoma among patients older than 35 years of age.