The classic feature of gynecomastia is male breast enlargement with soft, compressible, and mobile subcutaneous chest tissue palpated under the areola of the nipple in contrast to softer fatty tissue. This enlargement may occur on one side or both. Dimpling of the skin and nipple retraction are not typical features of gynecomastia. Milky discharge from the nipple is also not a typical finding, but may be seen in a gynecomastic individual with a prolactin secreting tumor. An increase in the diameter of the areola and asymmetry of chest tissue are other possible signs of gynecomastia.

Males with gynecomastia may appear anxious or stressed due to concerns about the possibility of having breast cancer.

When gigantomastia occurs in young women during puberty, the medical condition is known as "juvenile macromastia" or "juvenile gigantomastia" and sometimes as "virginal breast hypertrophy" or "virginal mammary hypertrophy". Along with the excessive breast size, other symptoms include red, itchy lesions and pain in the breasts. A diagnosis is made when an adolescent's breasts grow rapidly and achieve great weight usually soon after her first menstrual period. Some doctors suggest that the rapid breast development occurs before the onset of menstruation.

Some women with virginal breast hypertrophy experience breast growth at a steady rate for several years, after which the breasts rapidly develop exceeding normal growth. Some adolescent females experience minimal or negligible breast growth until their breasts suddenly grow very rapidly in a short period of time. This may cause considerable physical discomfort. Women suffering VBH often experience an excessive growth of their nipples as well. In severe cases of VBH, hypertrophy of the clitoris occurs.

At the onset of puberty, some females with who have experienced little or no breast development can reportedly reach three or more cup sizes within a few days (see below).

The indication is a breast weight that exceeds approximately 3% of the total body weight. There are varying definitions of what is considered to be excessive breast tissue, that is the expected breast tissue plus extraordinary breast tissue, ranging from as little as up to with most physicians defining macromastia as excessive tissue of over . Some resources distinguish between macromastia (Greek, "macro": large, "mastos": breast), where excessive tissue is less than 2.5 kg, and gigantomastia (Greek, "gigantikos": giant), where excessive tissue is more than 2.5 kg. The enlargement can cause muscular discomfort and over-stretching of the skin envelope, which can lead in some cases to ulceration.

Hypertrophy of the breast can affect the breasts equally, but usually affects one breast more than the other, thereby causing asymmetry, when one breast is larger than the other. The condition can also individually affect the nipples and areola instead of or in addition to the entire breast. The effect can produce a minor size variation to an extremely large breast asymmetry. Breast hypertrophy is classified in one of five ways: as either pubertal (virginal hypertrophy), gestational (gravid macromastia), in adult women without any obvious cause, associated with penicillamine therapy, and associated with extreme obesity. Many definitions of macromastia and gigantomastia are based on the term of "excessive breast tissue", and are therefore somewhat arbitrary.

The changes in fibrocystic breast disease are characterised by the appearance of fibrous tissue and a lumpy, cobblestone texture in the breasts. These lumps are smooth with defined edges, and are usually free-moving in regard to adjacent structures. The bumps can sometimes be obscured by irregularities in the breast that are associated with the condition. The lumps are most often found in the upper, outer sections of the breast (nearest to the armpit), but can be found throughout the breast. Women with fibrocystic changes may experience a persistent or intermittent breast aching or breast tenderness related to periodic swelling. Breasts and nipples may be tender or itchy.

Symptoms follow a periodic trend tied closely to the menstrual cycle. Symptoms tend to peak in the days and, in severe cases, weeks before each period and decrease afterwards. At peak, breasts may feel full, heavy, swollen, and tender to the touch. No complications related to breastfeeding have been found.

Gynecomastia is an endocrine system disorder in which there is a non-cancerous increase in the size of male breast tissue. Psychological distress may occur.

The development of gynecomastia is usually associated with benign pubertal changes. However, 75% of pubertal gynecomastia cases resolve within two years of onset without treatment. In rare cases, gynecomastia has been known to occur in association with certain disease states. The pathologic causes of gynecomastia are diverse and may include Klinefelter syndrome, certain cancers, endocrine disorders, metabolic dysfunction, various medications, or may occur due to a natural decline in testosterone production. Disturbances in the endocrine system that lead to an increase in the ratio of estrogens/androgens are thought to be responsible for the development of gynecomastia. This may occur even if the levels of estrogens and androgens are both appropriate but the ratio is altered. Diagnosis is based on signs and symptoms.

Conservative management of gynecomastia is often appropriate as the condition commonly resolves on its own. Medical treatment of gynecomastia that has persisted beyond two years is often ineffective. Medications such as aromatase inhibitors have been found to be effective in rare cases of gynecomastia from disorders such as aromatase excess syndrome or Peutz–Jeghers syndrome, but surgical removal of the excess tissue is usually required.

Gynecomastia is common. Physiologic gynecomastia develops in up to 70% of adolescent boys. Newborns and adolescent males often experience temporary gynecomastia due to the influence of maternal hormones and hormonal changes during puberty, respectively.

Breast atrophy is the normal or spontaneous atrophy or shrinkage of the breasts.

Breast atrophy commonly occurs in women during menopause when estrogen levels decrease. It can also be caused by hypoestrogenism and/or hyperandrogenism in women in general, such as in antiestrogen treatment for breast cancer, in polycystic ovary syndrome (PCOS), and in malnutrition such as that associated with eating disorders like anorexia nervosa or with chronic disease. It can also be an effect of weight loss.

In the treatment of gynecomastia in males and macromastia in women, and in hormone replacement therapy (HRT) for trans men, breast atrophy may be a desired effect.

Examples of treatment options for breast atrophy, depending on the situation/when appropriate, can include estrogens, antiandrogens, and proper nutrition or weight gain.

Adipomastia, or lipomastia, also known colloquially as fatty breasts, is a condition defined as an excess of skin and adipose tissue in the breasts without true breast glandular tissue. It is commonly present in men with obesity, and is particularly apparent in men who have undergone massive weight loss. A related/synonymous term is pseudogynecomastia. The condition is different and should be distinguished from gynecomastia ("women's breasts"), which involves true glandular breast development in a male. The two conditions can usually be distinguished easily by palpation to check for the presence of glandular tissue. Another difference between the conditions is that breast pain/tenderness does not occur in pseudogynecomastia. Sometimes, gynecomastia and pseudogynecomastia are present together; this is related to the fact that fat tissue expresses aromatase, the enzyme responsible for the synthesis of estrogen, and estrogen is produced to a disproportionate extent in men with excessive amounts of fat, resulting in simultaneous glandular enlargement.

In ICD-10 the condition is called "diffuse cystic mastopathy", or, if there is epithelial proliferation, "fibrosclerosis of breast". Other names for this condition include "chronic cystic mastitis", "fibrocystic mastopathy" and "mammary dysplasia". The condition has also been named after several people (see eponyms below). Since it is a very common disorder, some authors have argued that it should not be termed a "disease", whereas others feel that it meets the criteria for a disease. It is not a classic form of mastitis (breast inflammation).

This condition is also known as constricted breasts, tubular breasts, snoopy breasts (may be considered insulting), herniated areolar complexes, conical breast, domen nipple, lower pole hypoplasia and hypoplastic breasts.

Tuberous breasts are not simply small or underdeveloped breasts. The effect of the condition on the appearance of the breast can range from mild to severe, and typical characteristics include: enlarged, puffy areola, unusually wide spacing between the breasts, minimal breast tissue, sagging, higher than normal breast fold, and narrow base at the chest wall. The condition can cause low milk supply in breastfeeding women. However, other physical aspects of fertility and pregnancy are not affected by the condition.

Breast pain is a medical symptom that is most often associated with a developing disease or condition of the breast. These are usually benign breast diseases or conditions such as mastalgia, mastodynia, and fibrocystic breast changes. These disorders are painful and associated with lumps. Some breast pain is normal and associated with the changes that accompany puberty, pregnancy, lactation and menopause. The pain can be in one breast or both. The pain may constant, cyclical, or present only on palpation or when it is touched.

Cyclical breast pain (cyclical mastalgia) is often associated with fibrocystic breast changes or duct ectasia and thought to be caused by changes of prolactin response to thyrotropin. Some degree of cyclical breast tenderness is normal in the menstrual cycle, and is usually associated with menstruation and/or premenstrual syndrome (PMS).

Noncyclical breast pain has various causes and is harder to diagnose. Noncyclical pain has frequently its root cause outside the breast. Some degree of non-cyclical breast tenderness can normally be present due to hormonal changes in puberty (both in girls and boys), in menopause and during pregnancy. After pregnancy, breast pain can be caused by breastfeeding. Other causes of non-cyclical breast pain include alcoholism with liver damage (likely due to abnormal steroid metabolism), mastitis and medications such as digitalis, methyldopa (an antihypertensive), spironolactone, certain diuretics, oxymetholone (an anabolic steroid), and chlorpromazine (a typical antipsychotic). Also, shingles can cause a painful blistering rash on the skin of the breasts.

Other physical symptoms of menopause include lack of energy, joint soreness, stiffness, back pain, breast enlargement, breast pain,

heart palpitations, headache, dizziness, dry, itchy skin, thinning, tingling skin, weight gain, urinary incontinence,

urinary urgency,

interrupted sleeping patterns, heavy night sweats, hot flashes.

Micromastia (also called hypomastia, breast aplasia, breast hypoplasia, or mammary hypoplasia) is a medical term describing the postpubertal underdevelopment of a woman's breast tissue. Just as it is impossible to define 'normal' breast size, there is no objective definition of micromastia. Breast development is commonly asymmetric and one or both breasts may be small. This condition may be a congenital defect associated with underlying abnormalities of the pectoral muscle (as in Poland's syndrome), related to trauma (typically surgery or radiotherapy) or it may be a more subjective aesthetic description.

Self perceived micromastia involves a discrepancy between a person's body image, and her internalized images of appropriate or desirable breast size and shape. Societal ideals over breast size vary over time, but there exist many conceived ideas involving breasts and sexual attractiveness and identity across different cultures.

During the transition to menopause, menstrual patterns can show shorter cycling (by 2–7 days); longer cycles remain possible. There may be irregular bleeding (lighter, heavier, spotting). Dysfunctional uterine bleeding is often experienced by women approaching menopause due to the hormonal changes that accompany the menopause transition. Spotting or bleeding may simply be related to vaginal atrophy, a benign sore (polyp or lesion), or may be a functional endometrial response. The European Menopause and Andropause Society has released guidelines for assessment of the endometrium, which is usually the main source of spotting or bleeding.

In post-menopausal women, however, any genital bleeding is an alarming symptom that requires an appropriate study to rule out the possibility of malignant diseases.

Symptoms that may appear during menopause and continue through postmenopause include:

- painful intercourse

- vaginal dryness

- atrophic vaginitis – thinning of the membranes of the vulva, the vagina, the cervix, and the outer urinary tract, along with considerable shrinking and loss in elasticity of all of the outer and inner genital areas.

Hypoestrogenism, or estrogen deficiency, refers to a lower than normal level of estrogen, the primary sex hormone in women. In general, lower levels of estrogen may cause differences in the breasts, genitals, urinary tract, and skin.

Hypoestrogenism is most commonly found in women who are postmenopausal, have premature ovarian failure, or are suffering from amenorrhea; however, it is also associated with hyperprolactinemia and the use of gonadotropin-releasing hormone (GnRH) analogues in treatment of endometriosis. It has also been linked to scoliosis and young women with type 1 diabetes mellitus.

Presentations of low estrogen levels include hot flashes, headaches, lowered libido, and breast atrophy. Reduced bone density leading to secondary osteoporosis and atrophic changes such as pH change in the vagina is also linked to hypoestrogenism.

Low levels of estrogen can lead to dyspareunia and limited genital arousal because of changes in the four layers of the vaginal wall.

Hypoestrogenism is also considered one of the major risk factors for developing uncomplicated urinary tract infections (UTIs) in postmenopausal women who do not take hormone replacement therapy.

Micromastia can be congenital or disorder and may be unilateral or bilateral. Congenital causes include ulnar–mammary syndrome (caused by mutations in the TBX3 gene), Poland syndrome, Turner syndrome, and congenital adrenal hyperplasia. There is also a case report of familial hypoplasia of the nipples and athelia associated with mammary hypoplasia that was described in a father and his daughters. Acquired causes of micromastia include irradiation in infancy and childhood and surgical removal of prepubertal breast bud.

An estrogen-dependent condition, disease, disorder, or syndrome, is a medical condition that is, in part or full, dependent on, or is sensitive to, the presence of estrogenic activity in the body.

Known estrogen-dependent conditions include mastodynia (breast pain/tenderness), breast fibroids, mammoplasia (breast enlargement), macromastia (breast hypertrophy), gynecomastia, breast cancer, precocious puberty in girls, melasma, menorrhagia, endometriosis, endometrial hyperplasia, adenomyosis, uterine fibroids, uterine cancers (e.g., endometrial cancer), ovarian cancer, and hyperestrogenism in males such as in certain conditions like cirrhosis and Klinefelter's syndrome.

Such conditions may be treated with drugs with antiestrogen actions, including selective estrogen receptor modulators (SERMs) such as tamoxifen and clomifene, estrogen receptor antagonists such as fulvestrant, aromatase inhibitors such as anastrozole and exemestane, gonadotropin-releasing hormone (GnRH) analogues such as leuprolide and cetrorelix, and/or other antigonadotropins such as danazol, gestrinone, megestrol acetate, and medroxyprogesterone acetate.

Signs and symptoms of breast cysts include:

- A smooth, easily movable round or oval breast lump with distinct edges

- Breast pain or tenderness in the area of the lump

- Increased lump size and tenderness just before menstruation

- Decreased lump size and resolution of other signs and symptoms after menstruation

- Having one or many simple breast cysts does not increase a person's risk of breast cancer.

Lumps in the breast are often not found during self-examinations or physical exams. However, in some cases they can be felt at touch, especially if they are larger.

Breasts are usually lumpy or nodular as a result of the hormonal changes that women go through during their menstrual cycle. However, new breast lumps should always be referred to a specialist.

Fluid leaking from a cyst, as may happen due to puncture or vigorous compression during mammography, or due to seatbelt injury in the course of an automobile accident, may trigger an aseptic inflammation in the surrounding breast tissue.

Breast diseases can be classified either with disorders of the integument, or disorders of the reproductive system. A majority of breast diseases are noncancerous.

Breast tension is a constellation of symptoms involving the breasts including:

- Breast tenderness

- Breast pain

- Breast engorgement

Symptoms: The breasts are swollen and oedematous, and the skin looks shiny and diffusely red. Usually the whole of both breasts are affected, and they are painful. The woman may have a fever that usually subsides in 24 hours. The nipples may become stretched tight and flat which makes it difficult for the baby to attach and remove the milk. The milk does not flow well.

A fever may occur in 15 percent, but is typically less than 39 degrees C and lasts for less than one day.

Breast engorgement occurs in the mammary glands due to expansion and pressure exerted by the synthesis and storage of breast milk. It is also a main factor in altering the ability of the infant to latch-on. Engorgement changes the shape and curvature of the nipple region by making the breast inflexible, flat, hard, and swollen. The nipples on an engorged breast are flat.

Engorgement usually happens when the breasts switch from colostrum to mature milk (often referred to as when the milk "comes in"). However, engorgement can also happen later if lactating women miss several nursings and not enough milk is expressed from the breasts. It can be exacerbated by insufficient breastfeeding and/or blocked milk ducts. When engorged the breasts may swell, throb, and cause mild to extreme pain.

Engorgement may lead to mastitis (inflammation of the breast) and untreated engorgement puts pressure on the milk ducts, often causing a plugged duct. The woman will often feel a lump in one part of the breast, and the skin in that area may be red and/or warm. If it continues unchecked, the plugged duct can become a breast infection, at which point she may have a fever or flu-like symptoms.

A breast cyst is a fluid-filled sac within the breast. One breast can have one or more breast cysts. They are often described as round or oval lumps with distinct edges. In texture, a breast cyst usually feels like a soft grape or a water-filled balloon, but sometimes a breast cyst feels firm.

Breast cysts can be painful and may be worrisome but are generally benign. They are most common in pre-menopausal women in their 30s or 40s. They usually disappear after menopause, but may persist or reappear when using hormone therapy. They are also common in adolescents.

Breast cysts can be part of fibrocystic disease. The pain and swelling is usually worse in the second half of the menstrual cycle or during pregnancy.

Treating breast cysts is usually not necessary unless they are painful or cause discomfort. In most cases, the discomfort they cause may be alleviated by draining the fluid from the cyst. The cysts form as a result of the growth of the milk glands and their size may range from smaller than a pea to larger than a ping pong ball. Small cysts cannot be felt during a physical examination, and some large cysts feel like lumps. However, most cysts, regardless of their size cannot be identified during physical exams.

Breast cysts are not to be confused with "milk cysts" (galactoceles), which usually appear during weaning.