Master Invasive Ductal Carcinoma of Breast with Picmonic for Medicine

Invasive ductal carcinoma (IDC) is the most common type of breast cancer, accounting for ~80% of all invasive carcinoma types. IDC is associated with unilateral localization, is unifocal in nature, and presents with early metastases being more aggressive in nature.

Invasive ductal carcinoma usually presents as a firm ("rock hard") palpable mass with sharp margins.

In advanced stages, both skin dimpling and nipple retraction can occur. Cooper's ligaments are the breasts' suspensory ligaments and fuse with the underlying fascia located under the dermis eventually joining the deep fascia over the pectoralis muscle. As these ligaments provide structure to the breasts, infiltration (e.g. tumor) will produce a tethering effect, which leads to surface deformities such as nipple retraction and skin dimpling. Nipple retraction, in general, is of more concern symptomatically as is can indicate the presence of invasion or inflammatory nipple disease.

Spiculated margins consists of tissue radiating from an ill-defined mass, leading to a stellate ("spiked") appearance. The spiculation signals the retraction of tissue toward the tumor due to fibrosis, which is the result of a desmoplastic response.

Invasive ductal carcinoma can present with microcalcifications, which are calcific opacities often seen within the acini of the terminal duct lobular unit.

Histologically, a desmoplastic stromal reaction involving glandular, duct-like cells is a key finding.

The treatment of invasive carcinoma varies based on the staging of disease progression (i.e. early vs. advanced). Early disease can include a lymph node biopsy, systemic adjuvant therapy, and a lumpectomy with radiotherapy.

Chemotherapy is usually considered in more advanced cases of invasive ductal carcinoma. As this pertains to higher-risk patients the considerations of chemotherapy include lymph node involvement, tumor size (> 2 cm), indications of aggressiveness based on histology, and if related to triple negative breast cancer.

Radiotherapy is indicated in both early and advanced instances of invasive ductal carcinoma.