Breast cysts

Breast cysts are a common cause of referral to a specialised breast clinic, with up to 7% of all women presenting with a palpable cyst at some time during their life. The true incidence of cysts amongst the general population has been estimated to be as high as 20%. Cysts most commonly present in the 35-50-year age group as a lump (circumscribed, smooth, mobile) with a variable degree of discomfort or pain; up to 30% of such women will have multiple cysts. The aetiology of breast cysts is poorly understood. Although hormones have been implicated no consistent differences in hormonal levels in women with cysts have been identified.

A breast cyst arises from a breast lobule and on microscopy it is found to be lined by either a flattened epithelium (simple cysts) or by columnar secretory epithelium (apocrine cysts). Biochemically the contents of these two types of cysts are different. For example, simple cysts have high sodium and low potassium concentrations, with a sodium: potassium ratio of greater than 4 and a pH of less than 7.4. However, apocrine cysts have low sodium and high potassium concentrations, with a sodium: potassium ratio of less than 4 and a pH of greater than 7.4. The fluid from these cysts also contains a range of hormones, enzymes and growth factors.

The diagnosis of a cyst is confirmed by triple assessment. Mammography typically shows a well-defined opacity, although this may be difficult to demonstrate in dense breasts (Fig. 17.11(a)). Ultrasound examination, however, usually confirms that the lesion is a cyst (Fig. 17.11(b)). FNAC usually reveals straw-coloured fluid (sometimes bluish-green or brown). The fluid normally is not sent for cytological assessment. However, if the cyst is blood stained the fluid should be sent for cytological examination to exclude malignant cells and the presence of an intracystic growth. Following aspiration of a cyst the breast must be carefully examined to ensure that there has been complete resolution of the lump. If there is a residual palpable lump then this should undergo FNAC in case there is an underlying cancer.

Many surgeons will re-examine the breast 6-8 weeks later to determine if the cyst has re-accumulated. If so, it may be aspirated on a second and possibly third occasion. Although the management of cysts which repeatedly re-fill is debatable, it is probably best to excise them for therapeutic reasons as well as to exclude an underlying malignancy. Some authors have reported an increased tendency for cysts to repeatedly re-fill when associated with an underlying malignancy. The management of patients with multiple cysts also poses problems, as they may require repeated aspirations. A 3-month course of danazol may reduce the number and subsequent rate of cyst

Figure 17.17. Histological appearances seen in fibrocystic disease -fibrous obliteration of the normal breast parenchyma (x50).

formation. However, the side effects of danazol (see section on Treatment) must be taken into account when prescribing this form of therapy.

There is a continuing debate as to whether breast cysts are associated with an increased risk of developing breast cancer. Some studies have suggested that those with multiple, bilateral and apocrine cysts are at most risk. Other long-term studies have failed to demonstrate any link to subsequent development of malignancy.


This is a benign lesion which usually occurs under the areola in women who are pregnant or lactating. Clinically, the lesion is a smooth, well-defined lump and can become quite large. FNAC will result in the aspiration of milky fluid (can be inspissated) with resolution of the lump.

0 0

Post a comment