Finding a breast lump is cause for concern. But it may help to know that most breast lumps aren’t cancerous. In fact, 80 percent of women who have a breast biopsy find out that they don’t have breast cancer.

Of those who do have breast cancer, the most common location of the primary tumor is the upper outer quadrant of the breast. Of course, breast cancer can start anywhere there’s breast tissue. And everyone has breast tissue.

Read on to discover where breast cancer lumps are usually found, and what to do if you find one.

Several studies have found that the upper outer quadrant of the breast is the most frequent site for breast cancer occurrence. That would be the part of your breast nearest the armpit.

Read this article for more information about breast cancer.

It may help to visualize each breast as a clock with the nipple at the center. Facing your left breast, the upper outer quadrant is in the 12:00 o’clock to 3:00 o’clock position. Facing your right breast, the upper outer quadrant is in the 9:00 o’clock to 12:00 o’clock position.

The reason more breast cancer lumps occur in the upper outer part of the breast isn’t clear, but this area has a lot of glandular tissue. More women than men get breast cancer, but everyone has some breast tissue, and anyone can get breast cancer. Breast cancer lumps in men are usually found under or around the nipple.

These aren’t the only places breast cancer starts, though.

Parts of the breast

Breast tissue takes up a large area. It covers the pectoral muscles and extends from the breastbone to the armpit and up to the collarbone. Breast cancer can develop in any breast tissue. It can occur just under the skin or deep within the breast near the chest wall, where it’s difficult to feel.

The breasts are made up of glands, ducts, connective tissue, and fat. In women, each breast has 15 to 25 lobules, the glands that produce milk. Milk travels from the lobules to the nipple through the ducts. Men have fewer lobules and ducts.

All cancers start when cells begin to grow out of control, which can happen in any part of the breast. Most breast cancers begin in the ducts (ductal carcinoma).

There are certain characteristics of breast cancer lumps that may differentiate them from noncancerous lumps. But these are generalizations. It’s not something you should try to diagnose on your own. Doctors can’t always tell by touch alone, either.

Signs that a breast lump may be cancerous are:

  • it doesn’t hurt
  • it’s firm or hard
  • it’s bumpy
  • the edges are irregular
  • you can’t move it with your fingers
  • it’s growing or changing
  • it’s located in the upper outer quadrant of your breast

Keep in mind that having one or more of these characteristics doesn’t mean you have breast cancer. And breast cancer lumps can sometimes present very differently. They can be soft, moveable, and painful. And they can occur anywhere on the chest or armpit.

Cancerous breast lumps are similar in men and women.

A breast lump is the most common symptom of breast cancer. But breast cancer can appear as an area of thickening, rather than a distinguishable lump. Some types of breast cancer, such as inflammatory breast cancer, may not cause a lump at all.

Statistics from the Centers for Disease Control and Prevention (CDC) reveal that every year, there are about 255,000 new cases of breast cancer among women and 2,300 among men. Each year, about 42,000 women and 500 men die from this disease.

That’s why it’s important to have a doctor examine lumps that develop anywhere on your chest or underarm.

Benign breast disease is more common than breast cancer among women. There are many kinds of breast disorders, many of which present with a breast lump.

For men and women, signs that a breast lump may not be cancerous are:

  • it’s tender or hurts
  • it feels soft or rubbery
  • it’s smooth and round
  • you can easily move it using the pads of your fingers
  • it’s getting smaller

In women, breast cancer lumps are usually found in the upper outer quadrant of the breast. In men, they’re usually found near the nipple. Regardless of gender, breast cancer can start anywhere there’s breast tissue, from the breastbone to the armpit to the collarbone.

Most breast lumps turn out to be something other than breast cancer. And localized breast cancer is highly treatable, with an overall 5-year relative survival rate of 99 percent.

You can help catch breast cancer before it spreads by familiarizing yourself with how your breasts normally look and feel. One way to do this is to perform a monthly breast self-exam. If you discover a lump or notice other changes to the way your breasts look or feel, contact a doctor right away.

At your appointment, you should learn about breast cancer screening recommendations, your personal risk factors, and other warning signs of breast cancer.