Inflammatory breast cancer: Clinical sciences

Inflammatory breast cancer is a highly aggressive form of locally advanced breast cancer. Due to similarities in physical appearance, inflammatory breast cancer can sometimes be mistaken for benign diseases such as acute mastitis. Therefore, careful consideration must be given to rule out underlying malignancy if the benign disease doesn’t respond or quickly resolve with treatment.

When assessing a patient with a chief concern suggestive of inflammatory breast cancer, the first step is to obtain a focused history and physical exam, as well as labs such as CBC, CMP, LFTs, and Alkaline Phosphatase. Now, history might reveal breast pain, and a firm or enlarged breast, with rapid onset of symptoms, usually within 6 months. Some patients may report breast pruritus, swollen lymph nodes in the axilla or above the clavicle, fever, or even a recent history of suspected acute mastitis that hasn’t responded to antibiotics.

On the other hand, a physical exam typically shows a warm, tender breast, with extensive erythema that involves at least one-third of the breast, and thickened skin. A very common skin finding is called peau d’Orange. This occurs when tumor microemboli block dermal lymphatics, leaving portions of the breast with an edematous and dimpled orange-peel appearance. While peau d’Orange is highly associated with inflammatory breast cancer, it is important to remember that it might not always be present!

Other possible findings on physical exam include nipple changes, such as flattening or retraction, a palpable underlying breast mass, and regional lymphadenopathy, most commonly in the axilla. Finally, labs can show leukocytosis, and possibly elevated transaminases or alkaline phosphatase, which is concerning for metastatic disease to the liver or bones, respectively.

Here’s a clinical pearl for you! Significant fever, leukocytosis, and acute onset within a few days are rare in inflammatory breast cancer but common in acute mastitis. While these findings on their own can’t rule out an underlying malignancy, their prompt response to treatment with resolution can support a benign diagnosis.

Alright, now that we’ve finished our history and physical exam, let’s move on to imaging. To start, obtain a diagnostic mammogram of the affected breast as well as a screening mammogram of the other breast. Also, get an ultrasound of the breasts and their regional lymph node basins.

Okay, let’s go over the simple stuff first. If the mammogram and ultrasound do not show any signs concerning for breast cancer, consider an alternative diagnosis, such as the previously mentioned acute mastitis.

Let’s switch gears and talk about findings that are concerning for inflammatory breast cancer. Keep in mind that you’re looking for evidence of underlying invasive breast cancer and that inflammatory breast cancer does not have specific or unique radiographic characteristics. On a mammogram, you might encounter skin thickening, increased breast density, and evidence of edema or trabeculation, which refers to the thickening of fibrous septa within the breast. You may or may not find an underlying breast mass or the presence of calcifications. Ultrasound will also show skin thickening and edema, and possibly an underlying mass or regional lymphadenopathy. If you see any of these signs, suspect inflammatory breast cancer.

Ok, now that initial imaging is done, the next step is to get a breast biopsy. For inflammatory breast cancer, this means a core needle biopsy and typically two skin punch biopsies as well. While the vast majority of inflammatory breast cancers result from invasive ductal carcinoma, invasive lobular carcinoma is possible, too. The core needle biopsy will show malignant epithelial cells that have invaded through the basement membrane of the breast duct or lobule.