Invasive Ductal Carcinoma

Invasive ductal carcinoma NOS, or no special type, is the most common type of breast cancer representing 65% to 75% of mammary carcinomas (1,2). Depending on the size of the lesion, size of the breast, and proximity of the lesion to the skin, patients can present with a hard, fixed, palpable mass that may cause skin thickening and retraction (Fig. 8.1). If the cancer is in the subareolar area, patients may describe progressive flattening of the nipple, nipple deviation, inversion, or retraction (Fig. 8.2) or changes in the periareolar area (Fig. 8.3). When more advanced, the patient may present with skin ulceration (Fig. 8.4), a mass that protrudes or fungates through the skin (Fig. 8.5), more The focus of this chapter is on breast cancers that present with a mass detected on physical examination or with imaging. Invasive ductal carcinoma NOS is the most common type of breast cancer followed in frequency by invasive lobular carcinoma. Also discussed are relatively common variants of invasive ductal carcinoma including tubular, mucinous, papillary, medullary, and metaplastic carcinomas. It is important to emphasize, however, that there are additional variants of invasive ductal carcinoma that, because of their rarity, are beyond the scope of this book and not discussed. They include squamous, apocrine, adenoid cystic, secretory, neuroendocrine, cystic hypersecretory, cribriform, small cell, lipid rich, glycogen rich, and invasive micropapillary carcinomas (1,2). Evaluation and Imaging Features of Malignant Breast Masses 8