Cyst vs Tumor: Key Differences

If you find a new lump, mass, or growth anywhere on your body, you tend to assume the worst and think it’s cancer. But not all growths are cancerous tumors. Many growths are benign tumors and cysts that do not require treatment or are easily treatable. On the other hand, some growths are malignant and need to be treated. Please continue reading to learn the key differences between cysts and tumors.

What are cysts?

Cysts are abnormal fluid-filled sacs or capsules that can develop in many different parts of the body, including the skin, genitals, and internal organs. The fluid inside a cyst can be watery, jelly-like, cheesy, gooey, or waxy. Cysts develop due to a clogged duct, parasitic infection, cell wall defect, or injury to the blood vessels.

For example, a sebaceous cyst can develop when dead skin cells multiply and clog a hair follicle. Epidermoid cysts form due to hair follicle degeneration or damage. Pilar cysts or trichilemmal cysts are benign cysts that form in the skin of the scalp. Women with an underlying medical condition called polycystic ovary syndrome develop multiple ovarian cysts. Hormonal changes in women can lead to the formation of breast cysts. People with cystic acne develop painful, pus-filled cysts in their skin. Ganglion cysts form near tendons or joints of the wrists, hands, ankles, or feet and may require surgical removal.

Most cysts are benign. However, some cancers cause cysts. These cysts need to be surgically removed along with surrounding tissues. Surgical removal may be followed by chemotherapy and radiation therapy, depending on the type of cancer.

What are tumors?

Tumors form due to abnormal cell growth. They are solid masses of tissue and can develop in many different parts of the body, such as the skin, soft tissue, connective tissue, bones, glands, and internal organs.

Some tumors are benign, i.e., they do not contain cancerous cells. However, a benign tumor may need to be removed if it is causing pain or pressure on nearby tissue. Examples of benign tumors include lipomas, which are slow-growing tumors that contain fat cells. Fibroadenomas are benign breast tumors that can be seen on ultrasounds and mammograms and are usually left alone.

Malignant tumors contain cancer cells and require treatment. This usually involves surgically removing the tumor, followed by chemotherapy, radiation therapy, and other treatment modalities. Examples of malignant tumors include skin cancer, lung cancer, pancreatic cancer, osteosarcoma of the bone, and glioblastoma of the brain.

What is the difference between a cyst and a mass?

An abnormal mass can be solid or cystic. A cystic mass is a sac or capsule filled with fluid. In contrast, if the unusual mass is a solid mass (collection of abnormal cells), it is called a tumor. This can be a benign tumor or a malignant tumor.

How can you tell the difference between a solid and cystic mass?

It is not possible to tell the difference between a tumor and a cyst or a solid and cystic mass. The only way to be certain is to see your healthcare provider. They will obtain a medical history, perform a physical exam, order laboratory tests and diagnostic imaging studies, and make a definitive diagnosis of cyst or tumor.

With that said, some of the features of cysts and tumors are as follows:

Cysts

Cysts are sore or tender to the touch.
They may appear red or irritated.
There can be a “head” (pore or blackhead) at the center of a cyst.
A cyst may leak fluid that is white, yellow, or green in color.
Most cysts will move around under the skin when you press on them.

Tumors

A tumor usually feels firm or solid to the touch.
It can appear suddenly and grow rapidly in size.
There is no head (pore) at the center.
There is no fluid leakage from the mass.
It is fixed under the skin’s surface and does not move when you press on it.

How can a radiologist tell the difference between a cyst and a tumor?

A radiologist can use diagnostic imaging modalities such as ultrasounds, MRI scans, and CT scans to examine a mass located inside the body and tell the difference between cysts and tumors. These imaging studies show whether a mass is hollow and fluid-filled or if the abnormal cells form a solid mass. In some cases, the doctor may request a biopsy, which involves removing a small sample of tissue for examination in the laboratory.

Can a CT distinguish between a cyst and a tumor?

Yes, a CT scan can distinguish between cysts and tumors. A cyst that is uniform in appearance is almost always a benign cyst. However, if a cyst has both solid and cystic components, it could be a tumor. This tumor could be benign or malignant and will require further evaluation.

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