Approach to a breast mass and asymmetry: Clinical sciences

Breast mass or asymmetry can occur at any age and can be benign or malignant. Because there’s a wide range of causes for a breast mass or asymmetry, one helpful way to narrow down your differential is to categorize its onset in relation to pregnancy or lactation. It’s important to keep in mind that a new mass or asymmetry can carry a risk of malignancy, so timely diagnosis of the underlying cause is very important.

Your first step in assessing a patient with a new breast mass or asymmetry is to obtain a focused history and physical. On history, make sure to obtain information about the onset of the mass or asymmetry, associated pain, growth or changes in shape, as well as other symptoms, like skin changes or nipple discharge. Patients might report recent breast trauma, as well as fluctuation in size of the mass or associated symptoms with their menstrual cycle. In patients of child bearing age, make sure to ask if they’re currently pregnant or lactating. Additionally, patients might have certain risk factors such as early menarche or late menopause, history of breast cancer, ovarian cancer or other high risk lesions, genetic mutations like BRCA1 or BRCA2, or hormone replacement therapy .

Next, let’s move on to the physical exam. Your exam should include a complete clinical breast examination. On visual inspection you might see noticeable abnormalities or differences between the two breasts, including shape, size, dimpling, and skin or nipple changes. On palpation, you might feel a distinct mass, hardness of the breast or even elicit nipple discharge. Additionally, you might even find palpable lymphadenopathy of the cervical, clavicular, and axillary nodes.

The next step in our diagnostic work up is imaging. You may choose to order an ultrasound or mammogram. The modality of choice will depend on one factor: is the patient currently pregnant or lactating?

Alright, let’s start with patients who are pregnant or lactating. In this case, breast ultrasound is a safe diagnostic modality of choice. To effectively narrow down your differential diagnosis, you should always incorporate the patient’s clinical picture with your ultrasound findings.

Okay, let's discuss our first set of findings that may point to galactocele. On history, a pregnant or lactating patient might report a breast lump that has been progressively increasing in size. Physical exam reveals a solitary, firm, mobile breast mass that might be tender. In addition, you might see bilateral milky nipple discharge. Now, if on ultrasound, you see a solitary, thin-walled, fluid filled anechoic lesion, you should consider a galactocele. Next, you should perform an aspiration under ultrasound guidance to provide symptom relief, and to confirm your diagnosis if the initial ultrasound findings were unclear. A milky fluid aspirate would confirm the diagnosis of galactocele.

Ok, now, let’s go over another set of findings pointing to lactational mastitis with an abscess. History might reveal a progressive breast mass, mastalgia, and even a recent diagnosis of lactational mastitis that didn’t get any better with treatment. On physical exam, the breast is tender with a fluctuant mass. The overlying skin is indurated and erythematous, and the patient may have a fever. The initial ultrasound shows soft tissue edema and a hypoechoic fluid collection with possible loculations.

At this point, you should consider lactational mastitis with an abscess. Your next step is to collect a CBC, and perform an ultrasound guided aspiration of the abscess. If the CBC shows leukocytosis, and the aspirated fluid is purulent, your diagnosis is confirmed. You can send the aspirate for culture to tailor your antibiotic therapy. Keep in mind that the patient could have lactational mastitis without an abscess, which can be treated similarly with antibiotics without drainage.

Although galactocele and mastitis with an abscess are two of the most common causes of breast mass or asymmetry in pregnant or lactating patients, there are other important differentials to consider, especially if signs and symptoms persist with treatment. Some alternative diagnoses include malignancy, simple cysts, and fibroadenoma, along with some others we will discuss next.

Alright, let’s go all the way back and talk about patients who present with a breast mass that’s unrelated to pregnancy or lactation. For these patients, breast ultrasound and sometimes a mammogram are the best initial diagnostic modalities. Always consider the patient’s age when choosing which studies to obtain. In general, most patients under 30 will start with only an ultrasound. Also, keep in mind that these conditions may also affect pregnant or lactating patients, but the pathophysiology of the following conditions is generally unrelated to pregnancy or lactation.

Okay, let’s start with the most serious type of breast mass or asymmetry, breast cancer. On history, the patient might report a new painless mass, along with risk factors like a personal or family history of breast or ovarian cancer, age above 40, or even postmenopausal exogenous hormone use. Physical exam might reveal a unilateral hard fixed breast mass with skin or nipple changes and sometimes even bloody nipple discharge. Additionally, you might find palpable lymphadenopathy in the axilla.