What could a small hard lump be on the back of head?

A lump on the back of the head can cause concern. While there are many potential causes, most lumps turn out to be noncancerous. Still, it's important to see a doctor if you find a lump anywhere on your body, especially if it won't go away or keeps growing. In rare cases, a lump on the back of the head can be a sign of skin cancer or a more serious medical condition.

Possible causes of a lump on the back of the head:

* Sebaceous cyst. Sebaceous cysts are noncancerous growths of skin glands. They usually feel soft and moveable and may appear anywhere on the body.

* Lipoma. Lipomas are noncancerous growths of fat cells. They feel soft and doughy and can move around when you touch them. Lipomas can grow anywhere, but they're most common on the neck, back, shoulders, and arms.

* Dermoid cyst. Dermoid cysts are rare, noncancerous growths that can contain skin, hair, and other tissue. They're usually present at birth and can occur anywhere, but they're most common on the scalp, face, and neck.

* Pilomatrixoma. Pilomatrixomas are noncancerous growths of hair follicles. They usually feel hard and firm and may appear anywhere on the body, but they're most common on the head, neck, and arms.

* Hematomas. Hematomas are collections of blood outside the blood vessels. They usually occur after a bump or injury to the head.

* Infections. Bacterial or fungal infections can cause a lump on the back of the head.

* Skin cancer. In rare cases, a lump on the back of the head can be a sign of skin cancer. This is more likely if the lump is firm, crusty, bleeding, or doesn't heal.

When to see a doctor:

It's important to see a doctor if:

- The lump is growing quickly

- The lump is causing pain or other symptoms

- The lump has a change in size, shape, color, or texture

- The lump won't go away or keeps recurring

- You have multiple lumps on your body

- You're concerned about the lump

Your doctor may recommend tests, such as:

- Physical examination. The doctor will examine the lump and feel for any changes in size, shape, color, or texture.

- Biopsy. The doctor may take a small piece of tissue from the lump to examine under a microscope.

- Imaging tests. Imaging tests, such as MRI or CT scans, may be used to get a better view of the lump and its surroundings.

The course of treatment will depend on the cause of the lump. Noncancerous lumps may be left alone or removed surgically. Cancerous lumps will require more aggressive treatment.