Carcinoma of the male breast is a rare disease and represents only about 0.1% of all-site malignancy and is approximately 100 times less common than breast cancer in women, accounting for about 1% of all breast cancers. In the United States, male breast cancer accounts for fewer than 2000 cases per year and fewer than 500 deaths. The mean age at diagnosis is between 60 and 70 years, though men of any age can be affected with the disease. The average duration of symptoms before diagnosis approximates 2 years. This long duration is probably explained by the disregard of this rudimentary organ by the male adult and by the examining physician. Predisposing risk factors are thought to include radiation exposure, estrogen administration, and diseases associated with hyperestrogenism, such as cirrhosis or Klinefelter syndrome. An increased risk of male breast cancer has been reported in families, with an increased incidence seen in men who have a number of female relatives with breast cancer and those in whom a BRCA2 mutation on chromosome 13q is present. When there is a mutation in this gene, it confers a 5% to 10% lifetime risk for male breast cancer.
Because of the small amount of fatty
stroma and glandular tissue in the male breast, ulceration of the skin or
involvement of the nipple is an almost regular symptom of onset. Pain and
trauma are often given as the reasons for consulting the doctor. The tumor is
hard, irregular, and ﬁrmly attached to the overlying and underlying structures.
Ulceration is common. The axillary lymph nodes are usually enlarged.
Differential diagnosis from
gynecomastia can be made with fair certainty, taking the age of the patient
into account. Nodular tumors in the middle-aged man should be excised and
examined histologically. Even though a ﬁbroadenoma, an intracystic papilloma, a
lipoma or a benign epidermoid cyst usually leaves the skin over the nodule
freely movable in contrast to carcinoma, and though these nodules are also
softer than cancer, it is not recommended to exclude a malignant growth based
only on these clinical signs.
On cross section, the neoplasm is
ﬁrm, white, and inﬁltrating. A higher percentage of these growths are low-grade
adenocarcinomas, probably arising in the developmental anomalies of the sweat
glands or mammary epithelial structures. Pathologically, most carcinomas of the
male breast resemble the inﬁltrating form found in the female breast, with
inﬁltrating ductal cancer the most common tumor type. Lobular cancer has been
described as well. Inﬂammatory carcinoma and Paget disease of the nipple have
also been seen in men, but lobular carcinoma in situ has not. Lymph node
involvement and the hematogenous pattern of spread are similar to those found
in female breast cancer. The TNM staging system for male breast cancer is
identical to the staging system for female breast cancer.
Overall survival is similar to that
of women with similar stage breast cancers. The impression that male breast cancer has a worse prognosis may stem
from the tendency of these tumors to be diagnosed at a later stage. Prognostic
factors such as the size of the lesion and the presence or absence of lymph
node involvement correlate well with prognosis. Whether ploidy and number of
cells in S phase correlate with survival awaits more deﬁnitive data.
Estrogen-receptor and progester- one-receptor status and ER2/neu gene
ampliﬁcation are also being evaluated.
Although rare, various types of
sarcomas of the male breast have been reported. The majority are either
ﬁbrospindle or lymphosarcomas. These are rapidly growing tumors with early
attachment to the overlying skin and are highly malignant. Simple mastectomy is
employed. If lympho- or liposarcoma is disclosed by histologic examination,
postoperative irradiation should be given.