Fibrocystic Change Fibrocystic change, the most common lesion of the breast, is an imprecise term that covers a spectrum of clinical signs, symptoms, and histologic changes (76). The term refers to a histologic picture of fibrosis, cyst formation, and epithelial hyperplasia (83). Cysts arise from the breast lobules and are an aberration of normal breast involution (82). Macroscopic cysts occur in approximately 7% of women, and microscopic, nonpalpable cysts occur in about 40% of women (84). It is common in women 35 to 55 years of age, but rare in postmenopausal women not taking hormone therapy. The presence of estrogen seems necessary for the clinical symptoms to occur. This finding is supported by the observation that it is present bilaterally, increased in the perimenopausal age group, and responsive to endocrine therapy (85). In essence, a diagnosis of fibrocystic change can lead to significant patient anxiety but is of little clinical significance as long as malignancy is excluded (86). These lesions are associated with benign changes in the breast epithelium.
Cyst Fluid Analysis Investigators examined the electrolyte and protein content of cyst ﬂuid, but this is of little significance in the clinical management of fibrocystic disease. The potassium-to-sodium ratio is a marker that may be used to distinguish cyst subtypes (87). Cysts are either lined by apocrine epithelium with a high potassium-to-sodium ratio and a higher hormone or steroid concentration (type I); or by ﬂattened lobule epithelium with a low potassium-to-sodium ratio and a higher concentration of albumin, carcinoembryonic antigen, CA125, and steroid hormone–binding globulin (type II) (87). Apocrine cysts produce and secrete large amounts of prostate-specific antigen (PSA) (88). The role of this serine protease in proliferative breast disease is not fully understood.
Fibrocystic changes may produce an asymptomatic mass that is smooth, mobile, and potentially compressible. Fibrocystic change is more often accompanied by pain or tenderness and sometimes nipple discharge. In many cases, discomfort coincides with the premenstrual phase of the cycle, when the cysts tend to enlarge. Fluctuations in size and rapid appearance or disappearance of a breast mass are common. Multiple or bilateral masses appear frequently, and many patients have a history of a transient mass in the breast or cyclic breast pain. Cyclic breast pain is the most commonly associated symptom of fibrocystic changes.
Differential Diagnosis Pain, ﬂuctuation in size, multiplicity of lesions, and bilaterality are the features most helpful to differentiate fibrocystic disease from carcinoma. If a dominant mass is present, the diagnosis of cancer should be suspected until it is disproved by complete aspiration of a cyst, or histopathologic analysis if a mass is present after aspiration, or by breast imaging. Microscopic findings associated with fibrocystic disease include cysts (gross and microscopic), papillomatosis, adenosis, fibrosis, and ductal epithelial hyperplasia (89).
Diagnostic Tests Patients with cystic disease may have a discrete fibrocystic mass that is frequently indistinguishable from carcinoma, based on clinical findings. Mammography may be helpful, but there are no mammographic signs diagnostic of fibrocystic change. Ultrasonography is useful in differentiating a cystic from a solid mass. Characteristic findings on ultrasonography that confirm a simple cyst include the following:
Mass with thin walls
Absence of internal echoes
If these imaging criteria are not met, a tissue diagnosis of the mass usually requires a FNA, FNAC, or EB. The finding of a simple cyst by ultrasonography rules out carcinoma. Any lesion that is suspicious by mammography or ultrasonography should be biopsied.