Benign Disease  

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Benign Disease of the Breast

General

The breast consists of two types of tissues: glandular and stromal (supportive) tissues.  Lobules and ducts make up the glandular portion of the breast, while fatty and fibrous connective tissue make up the stroma.  Any of these tissues of the breast can undergo changes which can cause a patient to have symptoms.  Cysts, fibroadenomas, fibrocystic change, infection, and inflammation are all examples of processes which can manifest in the breast, but are considered benign. 

Women can experience various kinds of breast lumps and changes, particularly during their menstrual cycle, pregnancy, or with aging that can mimic breast cancer, even when they are not.  Since most breast lumps and changes are in fact benign, it is important to distinguish these lesions from their malignant counterparts, in order to alleviate undue anxiety.

The most common benign diseases of the breast are presented below.  These encompass the majority of presenting breast complaints in the ambulatory surgery setting.

Nipple Discharge

Processes which may cause nipple discharge

Nipple discharge is a symptomatic problem which causes patients both anxiety and discomfort.  It can occur in either sex, but predominantly occurs in females.  It is most often due to a benign process, and can occur at any age, from infancy to adulthood.  When evaluating nipple discharge, the first step is to determine whether it is a result of a physiologic or pathologic process.  For example, women using contraceptives or hormone replacement therapy can have non-clinically significant nipple discharge, secondary to the effects of the medications on the breast epithelium.

Physiologic discharges tend to occur only with compression of the nipple or breast and are characterized by multiple duct involvement. These discharges are most often bilateral, and their source is often revealed by a careful history.  After exclusion of malignancy by mammography, reassurance is often the only therapy necessary.

Nipple discharges are classified as pathologic if they are spontaneous, bloody, or associated with a mass.  They tend to be unilateral and confined to one duct, and their risk for malignancy increases in patients over 50 or when associated with positive mammographic or galactographic findings.  The most common cause for pathologic nipple discharge is an intraductal papilloma, a benign local proliferation of ductal epithelial cells.  Other causes include duct ectasia (second most common cause), cysts, and subareolar abscesses.

In either case, the work-up should include localization of the affected duct (or ducts), and examination for occult blood.  A diagnostic mammogram is useful for identifying non-palpable masses and calcifications.  All patients with a spontaneous, unilateral, or bloody discharge should be referred for surgical evaluation.  A terminal duct excision is both diagnostic and, for discharges that turn out to have a benign cause, therapeutic.

Fibroadenoma

Fibroadenoma

Fibroadenomas are among the most common benign tumors and are typically not considered to have malignant potential.  They are composed of stromal and epithelial elements and represent a hyperplastic process in a single, terminal ductal unit.  Within the breast, two kinds of breast stroma exist: intralobular and interlobular. Intralobular stroma contains lobules composed of 6-10 major ductal systems surrounded by a myxomatous stroma, and it is from this stroma that fibroadenomas arise.

They typically occur in younger women (teens to 30's), and present as palpable or non-palpable, oval, freely mobile, rubbery masses.  Usually a solitary lesion, they present in a range of sizes, from very small (<1 cm) to extremely large (up to 15 cm).  Although usually only a single lump presents itself, about 10-15% of women may have multiple masses, affecting both breasts.

Fibroadenomas are most often painless and appear to respond to hormonal changes.  During the reproductive years, and during pregnancy in particular, they may increase in size.  After menopause, they tend to regress in size.

Evaluation is usually made by ultrasound (for women under 30) or ultrasound/mammogram for women over 30.  On ultrasound, fibroadenomas are circumscribed, homogeneous, oval, hypoechoic masses, often with gentle lobulations and a smooth, thin, echogenic capsule.  On mammogram, they appear as circumscribed oval or round masses, which occasionally have coarse calcifications.

Definitive diagnosis, however, is made by fine needle aspiration or open biopsy, with FNA the preferred evaluation.  If a biopsy indicates that the lump is a fibroadenoma, the lump may be left in place or removed, depending on the patient and the lump. If left in place, it may be watched over time with physical examinations, mammograms, and ultrasounds. Alternatively, the lump may be surgically removed, depending on the features of the lump and the patient's preferences. Typically, however, approximately 50% of fibroadenomas will resolve on their own within 5 years, so conservative "watch and wait" treatment is plausible.

Fibrocystic Disease

Fibrocystic Disease

Fibrocystic breast disease (FBD) is the most common cause of breast lumps in women of childbearing age.  Although not generally considered a "disease" per say, fibrocystic change is a manifestation of normal physiologic changes, which occur in response to menstrual hormonal changes.  It is encountered so often, that some doctors consider it a normal variant.  The condition is characterized by freely mobile masses  (typically multiple) in the breast tissue, that are tender to palpation.  Breast tissue is often described as "lumpy and bumpy".

Although the exact cause of fibrocystic change is unknown, it is thought to be a result of the way breast tissue responds to monthly hormonal changes (estrogen, progesterone, and even prolactin) in premenopausal women.  This comes from the observation that symptoms are generally worse before the onset of menses and improve afterwards.  In addition, fibrocystic change is rare in postmenopausal women, unless receiving hormone replacement therapy (HRT).

The symptoms of fibrocystic breast disease can range from mild to severe.  Patients may report feeling lumps enlarging or regressing, breast tenderness (particularly to touch), nipple discharge (prolactin stimulated from lump pressing against a milk gland) and changes in nipple sensation, such as itching.

Diagnosis is made with a detailed medical history and physical exam, with emphasis on changes in symptomology with time (before, during , and after a menstrual cycle).  Mammography and ultrasound may be helpful, except in younger women with denser breasts.  Definitive diagnosis can be made with FNA or excisional biopsy, although a good clinical exam is often all that is necessary.  Treatment is mainly reassurance and pain relievers (aspirin, etc.).

Breast Cyst

Simple and Complex Breast Cysts

Breast cysts are very similar in nature to fibrocystic breast change, however, unlike the latter, they exist as true "cysts".  Like FBD, they tend to occur in response to hormonal changes; typically when the breast is stimulated by an excess of estrogen.  As such, they are the most common cause of a breast mass in women in their 40's and 50's, or postmenopausal women taking HRT.  They are less prevalent in premenopausal women under 40.

Breast cysts are classified according to how they appear on ultrasound.  Simple cysts are well-defined, round or oblong masses which the ultrasound signal passes readily through.  They look very dark on ultrasound and have a thin, distinct, border.  Complex cysts, on the other hand, may be less well-defined.  The ultrasound image is usually grayish-black, with fuzzy edges, as the signal does not pass easily through them. 

On physical exam, it is often difficult to distinguish a cyst from a solid mass.  Ultrasound or FNA must be employed to establish a definitive diagnosis.  Most aspirated cysts yield straw-colored or green-tinged fluid and the cyst resolved following aspiration (the capsule involutes) .  Unless bloody fluid or a residual mass remains following aspiration, routine cytologic examination of cyst fluid is not indicated, as there is a low likelihood of cancer.  Bloody fluid or a residual mass does, however, warrant further evaluation with diagnostic mammography and biopsy, in addition to cytologic analysis of aspirated fluid

Patients with a solitary breast cyst should be reexamined four to six weeks after cyst aspiration to determine if the cyst has recurred.  Aspiration is still an appropriate first step in the management of a breast cyst, but clinical follow-up after aspiration is essential.