Gynecomastia overview

# Overview
Gynecomastia is a benign male breast enlargement. Gynecomastia occurs due to increase estrogen to androgen ratio. Increased estrogen to androgen ratio can be physiological, such as seen during infancy, puberty and old age or pathological, which is due to obesity, steroid use, pharmacologic agents, medical conditions including chronic liver and renal failure or hypogonadism. However, most cases of the gynecomastia are idiopathic and asymptomatic. The diagnosis is primarily clinical. Other modalities used to diagnose gynecomastia include laboratory investigations such as blood hormone levels, renal function tests and liver function tests and imaging such as ultrasound or mammography. The treatment is usually supportive. Antiestrogens and surgical intervention can be considered in certain cases depending on physician and patient preference.

# Historical Perspective
Gynecomastia is derived from Greek words, gyne which means woman and mastos which means breast. The term was originally coined by Galen, a Greek physician. Gynecomastia has been a known concept since the days of Aristotle (384322 BC). The surgical management was initially discussed by Paulus, a Greek physician and later modified by Al-Zahrawi or Albucasis, an Andalusian surgeon.

# Classification
Gynecomastia has been classified by various systems mainly based on surgical management, the severity of gynecomastia, physical appearance, and etiology.

# Pathophysiology
The main pathophysiology behind gynecomastia is increased estrogen to androgen ratio which can occur through multiple mechanisms. These mechanisms can be physiological, pathological or pharmacological.

# Causes
Common known causes of gynecomastia include physiological hormonal changes, use of medications and pathological entities such as cirrhosis, hyperthyroidism, testicular tumors and hypogonadism. Less common causes include androgen insensitivity syndrome, Kallmann syndrome, defects of testosterone pathway and tumors.

# Differentiating gynecomastia from other diseases
Gynecomastia must be differentiated from other diseases that cause breast enlargement in men. These diseases include pseudo gynecomastia, breast cancer, breast abscess, and lipoma.

# Epidemiology and Demographics
Gynecomastia has the highest prevalence in elderly and neonatal age. Gynecomastia has trimodal age distribution with no racial preference.

# Risk Factors
Common risk factors in the development of gynecomastia include the use of medications, cirrhosis, and hyperthyroidism. The less common risk factors include aromatase overexpression, androgen insensitivity syndrome and testosterone pathway defects.

# Screening
There is insufficient evidence to recommend routine screening for gynecomastia.

# Natural History, Complications, and Prognosis
If left untreated patients with gynecomastia may progress to develop psychosocial stresses and rarely breast cancer. The majority of physiological gynecomastia is self-limited. Pathological gynecomastia has an excellent prognosis and responds well to treatment. Pharmacological gynecomastia responds very well to the cessation of the the offending agent.

# Diagnosis

## Diagnostic Criteria
There are no established criteria for the diagnosis of gynecomastia. Gynecomastia is diagnosed clinically after a thorough history and physical examination. Laboratory investigations, imaging and exclusion of other conditions like pseudogynecomastia and breast cancer, is also helpful in the diagnosis of gynecomastia.

## History and Symptoms
The hallmark of gynecomastia is breast enlargement. The majority of patients with gynecomastia are asymptomatic. Pain is the most common symptom of gynecomastia. Less common symptoms depend on the underlying cause.

## Physical Examination
Common physical examination findings of gynecomastia include breast enlargement with or without tenderness. Patients with gynecomastia are otherwise asymptomatic.

## Laboratory Findings
Gynecomastia is diagnosed clinically after a thorough history and physical examination. Gynecomastia which is recent in onset and tender on the examination should have serum concentrations of human chorionic gonadotropin (hCG), LH, testosterone, and estradiol measured. The hormonal levels may vary depending on the underlying cause.

## Electrocardiogram
There are no ECG findings associated with gynecomastia.

## X-ray
There are no x-ray findings associated with gynecomastia.

## CT scan
There are no CT scan findings associated with gynecomastia.

## MRI
There are no MRI findings associated with gynecomastia.

## Ultrasound
Gynecomastia is diagnosed clinically after a thorough history and physical examination. Ultrasound can be done in patients with gynecomastia when physical findings raise suspicion of a lump, abscess or breast cancer.

## Other Imaging Findings
Gynecomastia is diagnosed clinically after a thorough history and physical examination. Mammogram can be done in gynecomastia when physical findings of a patient raise suspicion of breast cancer.

## Other Diagnostic Studies
Gynecomastia is diagnosed clinically after a thorough history and physical examination. Laboratory investigations and imaging studies can be helpful in the diagnosis of gynecomastia. Other diagnostic study in the work up for gynecomastia include biopsy, which helps to confirm the diagnosis of breast cancer.

# Treatment

## Medical Therapy
Gynecomastia is usually a self-limited condition, reassurance and follow-ups are recommended. Causative medications should be withheld and any underlying condition leading to gynecomastia should be throughly investigated and treated. Pharmacologic therapy is beneficial for the first several months until fibrous tissue replaces the glandular tissue. Pharmacologic options include SERMs, androgens and aromatase inhibitors.

## Surgery
Surgery is not the first-line treatment option for patients with gynecomastia. Surgery is usually reserved for patients with either psychological stresses, extensive gynecomastia or failure of medical treatment. The type of surgical technique depends on the extent of gynecomastia.

## Primary Prevention
There are no established methods for the primary prevention of gynecomastia.

## Secondary Prevention
There are no established methods for the secondary prevention of gynecomastia.