Special Clinical Forms of Breast Cancer

Paget's Carcinoma

The basic lesion is usually an infiltrating ductal carcinoma, usually well differentiated, or a ductal carcinoma in situ (DCIS). The ducts of the nipple epithelium are infiltrated, but gross nipple changes are often minimal, and a tumor mass may not be palpable. The first symptom is often itching or burning of the nipple, with superficial erosion or ulceration. The diagnosis is established by biopsy of the erosion.

Paget's carcinoma is not common (about 1% of all breast cancers), but it is important because the nipple changes appear innocuous. These are frequently diagnosed and treated as dermatitis or bacterial infection, leading to delay in detection. When the lesion consists of nipple changes only, the incidence of axillary metastases is less than 5%, and the prognosis is excellent. When a breast mass is also present, the incidence of axillary metastases rises, with an associated marked decrease in prospects for cure by surgical or other treatment.

Inflammatory Carcinoma

This is the most malignant form of breast cancer and constitutes less than 3% of all cases. The clinical findings consist of a rapidly growing, sometimes painful mass that enlarges the breast. The overlying skin becomes erythematous, edematous, and warm. Often there is no distinct mass, since the tumor infiltrates the involved breast diffusely. The diagnosis should be made when the redness involves more than one-third of the skin over the breast and biopsy shows infiltrating carcinoma with invasion of the subdermal lymphatics. The inflammatory changes, often mistaken for an infection, are caused by carcinomatous invasion of the subdermal lymphatics, with resulting edema and hyperemia. If the physician suspects infection but the lesion does not respond rapidly (1-2 weeks) to antibiotics, biopsy is performed. Metastases tend to occur early and widely, and for this reason inflammatory carcinoma is rarely curable. Mastectomy is seldom indicated unless chemotherapy and radiation have resulted in clinical remission with no evidence of distant metastases. In these cases, residual disease in the breast may be eradicated. Radiation, hormone therapy, and chemotherapy are the measures most likely to be of value, rather than operation.

Breast Cancer Occurring during Pregnancy or Lactation

Breast cancer complicates approximately 1 in 3000 pregnancies. The diagnosis is frequently delayed, because physiologic changes in the breast may obscure the lesion. This results in a tendency of both patients and physicians to misinterpret findings and to delay biopsy. When the cancer is confined to the breast, the 5-year survival rate after mastectomy is about 70%. Axillary metastases are already present in 60-70% of patients, and for them the 5-year survival rate after mastectomy is only 30-40%. Pregnancy (or lactation) is not a contraindication to operation, and treatment should be based on the stage of the disease as in the nonpregnant (or nonlactating) woman. Overall survival rates have improved, since cancers are now diagnosed in pregnant women earlier than in the past. Breast-conserving surgery may be performed - and radiation and chemotherapy given - even during the pregnancy.