1. Cysts:

"Not all breast lumps are created equal. There can be many reasons why a woman may feel a lump in their breasts or see one on imaging, such as a mammogram or ultrasound. While we are always concerned that these may be cancerous, there can be benign reasons to have a lump. Cysts are another common cause and are fluid-filled round lesions within a 'sac' or lining. They can change in size on their own or can change with your menstruation. Lumps during your menstrual cycle, in general, are common as well and are referred to as fibrocystic changes. This is one of the main reasons why it's important to regularly do self-breast exams so you are familiar with how your normal breast feels.

"Breast imaging such as mammograms, ultrasounds, or an MRI are likely to differentiate between these various lumps. In certain instances, your doctor may recommend a biopsy or fine-needle aspiration to obtain a definitive diagnosis or may discuss removal of the mass completely."

—Smita R. Ramanadham, M.D., F.A.C.S.

2. Fat Necrosis:

"Fat necrosis is benign breast lump that usually happens after trauma to the breast, surgery, or injection of foreign material. In this case, the part of the fat in the breast dies and becomes calcified and hard and feels like a tumor. These are noncancerous and usually need surgery to rule out if they are painful or to differentiate from cancer."

—Gajendra Singh

3. Breast Abscess:

"An infection, categorized by pus in the breast tissue. Associated with pain and sometimes a fever, it's usually a complication of an infection of the skin. There's usually redness on the breast and antibiotics may fail. Your physician may feel a lump that is tender. It is easily diagnosed by ultrasound. And it's treatable."

—Lamia Kadir, MD

4. Intraductal Papilloma:

"Intraductal papilloma is a small growth within the milk ducts in a female breast. These may be associated with bloody nipple drainage and can sometimes result in a mass or lump. A blocked milk duct is another cause of a bump or mass to form in the female breast. Typically, this occurs during breastfeeding."

—Smita R. Ramanadham, M.D., F.A.C.S.

5. Fibroadenomas:

"Generally, about 20% of breast lumps are cancer. Fibroadenomas - these are the most common benign lumps. If you push on them, they are solid, round, rubbery lumps that move freely. They're usually painless. Women between 20 and 30 get them most often. They're also more common in African-American women. Fibroadenomas can be surgically removed. There are other types of non-cancerous breast conditions as well."

—Dr. Ricardo Castrellón

Every doctor presented here stressed the significance of making sure we're checking for lumps on the regular, so I want to echo their sentiments here as well.

According to the National Breast Cancer Foundation, the best time to examine your breasts is "7-10 days after their menstrual period starts which is also when their breasts are the least tender and lumpy."