INFLAMMATORY
CARCINOMA
Inflammatory or acute carcinoma, formerly designated as carcinomatous mastitis, is more often observed in patients with obese breasts or during pregnancy and lactation, from which is derived another older term, lactation cancer. Inflammatory carcinomas comprise approximately 1% to 5% of all breast cancers. This form is recognized clinically as a rapidly growing, highly malignant carcinoma, with infiltration of malignant cells into the lymphatics of the skin, which pro- duces a clinical picture that simulates a skin infection. There is not a specific histologic cell type. In the TNM staging system for breast cancer, inflammatory cancer has its own classification, T4d, and by definition, is staged as stage IIIb or above. (Stage IIIB breast cancers are locally advanced; stage IV breast cancer is cancer that has spread to other organs.) Because of the rapid growth of these tumors, the physical appearance of the breast is often different from that of patients with other stage III breast cancers.
Inflammatory breast cancer tends to
be diagnosed in younger women compared to other breast cancers, and it occurs
more frequently and at a younger age in blacks than in whites. Like other types
of breast cancer, inflammatory breast cancer can occur in men, but usually at an
older age than in women. There is some early evidence for an association
between family history of breast cancer and inflammatory cancers, but more
studies are needed.
The appearance of a rapidly widening
area of inflamed skin usually occurs early in the disease and may precede the
discovery of the underlying tumor. The dermal spread is caused by retrograde
extension of the cancer cells through the lymphatics of the skin. The majority
of cases are of the primary form, that is, when the patient has noted a small
tumor in the breast or axilla only a few weeks prior to the appearance of
inflammatory signs. The presence of the tumor in the secondary form antedates
the skin inflammation by months. The tumor might already have reached a large
size, or the skin changes may fall upon a mastectomy scar. The changes in the
skin are characterized by a reddish or purplish discoloration and edema
producing the characteristic orange peel effect. Multiple small nodules may
also be present. The inflamed discoloration may extend up the neck and down the
arm on the affected side, or across to the opposite breast and shoulder. A
low-grade fever, enlarged axillary nodes, and an elevated leukocyte count,
which may reach 15,000, accompany the carcinomatous invasion of the skin. Adenopathy
may extend to the groin, and the skin over the abdomen may be inflamed; hence
the term erysipeloid cancer has also been used. In a typical case the symptoms are usually less than 4 months in
duration. Treatment consists of chemotherapy, targeted surgery, radiation
therapy, and hormonal therapy, but 5-year survival is only in the range of 25%
to 50% with recurrences common. This is significantly lower than for patients
with other types of breast cancer. Chemotherapy is generally the first treatment
followed by targeted surgery. Additional treatments may include additional
chemotherapy, hormonal therapy, or the recently added modality of special
targeted therapy (such as trastuzumab) for patients
whose tumors overexpress the HER-2 tumor protein.
Tissue sections through a region
with inflammatory cancer exhibit relatively few signs of acute inflammation. The
paramount characteristic is the blockage of lymphatics and superficial blood
vessels with invading cancer cells. This same metastatic process into the sub-cutis
is seen in preparations from a lenticular cancer, or carcinoma en cuirasse,
where the invasion proceeds more slowly,
more diffusely, and without edema.
