The unique anatomic structure of the breast contributes to the wide variety of pathologic conditions that may occur. Each breast contains approximately 20 glandular units (lobes) composed of glands and adipose tissue (Fig. 127.1). Each lobe drains into a lactiferous duct, which fuses with other ducts to form lactiferous sinuses just below the skin. The lactiferous sinuses store milk during lactation. Disruption (obstruction, infection, inflammation) of the glandular system may occur at any time during a female’s lifetime but predominates between menarche and menopause. The breast’s diffuse vascular network predisposes it to hematogenous spread of malignancy, as well as infection.

Fig. 127.1 The breast contains approximately 20 glandular units (lobes), each composed of a tubuloalveolar gland and adipose tissue.

(From Iglehart JD, Kaelin CM. Diseases of the breast. In: Townsend CM, Beauchamp RD, Evers BM, et al, editors. Sabiston’s textbook of surgery. 17th ed. Philadelphia: Saunders; 2004.)

Virtually all breast conditions that occur in women are seen in men as well, including benign conditions such as fat necrosis, allergic and irritant dermatitis, mastitis and abscess, and mammary tuberculosis. Malignant entities such as adenocarcinoma of the breast, Paget disease of the nipple, and lymphoma occur less frequently in men than in women. Breast cancer in men accounts for less than 1% of the total number of breast malignancies diagnosed in the United States. However, in other areas in the world (e.g., central Africa), male breast cancer is significantly more common. Men are at higher risk for the development of malignant melanoma and basal cell carcinoma of the breast. One condition, gynecomastia, occurs exclusively in men.

Presenting Signs and Symptoms

Differential Diagnosis and Medical Decision Making

See Box 127.1 for an overview of causes of breast-related complaints.

Mastalgia

Breast pain, especially as an isolated symptom, can be thought of as originating from one of three broad categories: cyclic mastalgia, noncyclic mastalgia, or extramammary.

Cyclic mastalgia occurs in premenopausal women, is associated with worsening symptoms in the late luteal phase of the menstrual cycle, and accounts for two thirds of patients with mastalgia. The typical pain of cyclic mastalgia is “achy” or “heavy” and bilateral. Resolution with the onset of menses is very reassuring.

Findings on physical examination may be normal, or tender nodularities may be detected. Fibrocystic breast conditions (the term fibrocystic breast disease has been replaced by the term fibrocystic breast condition to emphasize that it represents a spectrum of histologic entities) are not associated with axillary lymphadenopathy, skin thickening, edema or discoloration, or nipple abnormalities such as retraction or discharge. The presence of any of these findings raises the probability that the patient has another condition instead of or in addition to cyclic mastalgia.

Noncyclic mastalgia may be caused by a variety of conditions ³ (Box 127.2). It may be constant or intermittent, but it is not associated with the menstrual cycle. Noncyclic mastalgia tends to be unilateral and localized to a discrete area. Women with noncyclic breast pain are generally older than 40 years, and the cause is likely to be related to an anatomic lesion in the breast. It is rare for breast cancer to have pain as the sole initial symptom.⁴

Extramammary breast pain can arise from the chest wall or from other sources. Although most of the conditions that cause isolated breast pain are not immediately life-threatening, some emergency conditions, including acute coronary syndrome and pulmonary embolism, can be accompanied by pain that appears to be originating from the breast.

Mondor disease (Fig. 127.2) is a superficial phlebitis of the lateral thoracic, thoracoepigastric, or superior epigastric vein. It typically occurs in middle-aged women. The condition can be unilateral or bilateral. It is often idiopathic but may be associated with other conditions.⁵ The classic Mondor cord is 2 to 3 mm in diameter and typically red and tender, tracks from the lateral margin of the breast across the costal margin, and extends from 2 to 30 cm. Any tenderness should resolve within weeks, but the cord may remain palpable for up to 6 months. There is no risk for systemic embolization.