A 61-year-old woman comes to the office due to skin puckering on the right breast. She first noticed the skin changes 3 months ago while on vacation and is concerned that they have not resolved. The patient does not use tobacco, alcohol, or recreational drugs. She exercises regularly and takes a daily multivitamin. Her last menstrual period was 8 years ago. Physical examination shows a prominent, nontender skin retraction without discoloration or swelling of the right breast. There is also a 6-cm irregular, immobile, firm mass in the right upper outer quadrant of the breast. The left breast appears normal. This patient's skin findings are likely due to malignant infiltration of which of the following structures?
Show Explanatory Sources
Breast cancer is the most commonly diagnosed malignancy in women in the United States and the second most common cause of cancer death in women. Invasive breast carcinoma typically presents as an irregularly shaped, adherent breast mass. The upper outer quadrants of the breast are the most common site of breast cancer. Overlying skin retractions (puckering) signal involvement of suspensory ligaments of the breast (ie, Cooper ligaments). Malignant infiltration of these ligaments causes fibrosis and shortening, leading to traction on the skin with distortion in breast contour.
(Choice A) Axillary lymph nodes are the most common site of metastasis for breast cancer. As malignant cells spread through the lymphatics, they can block cutaneous lymphatic flow, causing peau d'orange (thickened, dimpled skin like an orange peel). However, this finding is distinct from skin retractions and is associated with discoloration and swelling of the breast.
(Choices B and D) Lactiferous ducts connect the nipple to the mammary lobules to allow lactation. Malignant spread of ductal carcinoma through the ductal system may cause nipple discharge, whereas spread to the nipple surface causes Paget disease of the nipple (eg, eczematous exudate over the nipple and areola).
(Choice C) The internal mammary vein runs along the thoracic lymphatics, draining the medial portions of the breast, and may be a site of metastasis from lesions in that area. Spread to the vasculature often results in distant hematogenous metastasis.
Educational objective:
Invasive breast carcinoma typically presents as an irregularly shaped, adherent breast mass, most commonly in the upper outer quadrant. Malignant infiltration of suspensory ligaments of the breast can cause skin retractions.