Lipoma: what it is, whether it is dangerous, and what it looks like

A subcutaneous lump that can be felt under the fingers often turns out to be a lipoma — a soft fatty formation that grows slowly. In most cases such a formation is harmless and does not require intervention, but it should be examined by a doctor once. Below is what is known about lipoma, where it comes from, and how it differs from other nodules.

What a lipoma is

A lipoma (fatty tumor, adipose tumor) is a benign tumor of adipose tissue. It develops in the layer of loose subcutaneous connective tissue and can extend deeper, between muscles and vascular bundles, as far as the periosteum. The consistency is soft, the formation is painless and easily mobile, and it grows slowly.

Sizes range from a pea to several centimeters; when pressed, the nodule shifts slightly under the skin. Lipomas are common.

Is a lipoma cancer? The benign nature of a fatty tumor

No, a lipoma is not cancer. Benign tumors differ from malignant ones in that they grow only in one place and do not spread throughout the body; they are dangerous only when they compress vital organs. A lipoma is usually safe; very rarely a subcutaneous lipoma transforms into a liposarcoma — a malignant tumor of connective tissue. In the breast, liposarcoma is an extremely rare phenomenon.

What causes a lipoma

The cause has not been definitively established. A metabolic version is discussed: insufficiency of regulatory enzyme proteins due to duplication of the long arm of chromosome 12 (12q13-15), where the loci of the gene for the TAG lipase protein, which breaks down fats, are located. In other words, a lipoma grows not because fat is excessively deposited in adipocytes, but because the pathways for its breakdown are blocked.

Familial lipomatosis is inherited in an autosomal dominant manner and manifests at a young age.

Where a lipoma can occur: back, abdomen, neck, limbs

A lipoma can appear almost anywhere there is subcutaneous fat. It is most often found on the shoulders, chest, arms, back, buttocks, and thighs. A notable feature: formations often arise in areas poor in adipose tissue — on the upper back, in the shoulder girdle area, on the outer surface of the upper arm and thigh.

A lipoma on the abdomen, back, neck, or leg is, as a rule, the same formation rather than different diseases; the only thing that matters is whether the nodule interferes with movement or is cosmetically noticeable. A diffuse lipoma is distinguished separately — an accumulation of grape-like masses of fat without clear boundaries, in which the limb can significantly enlarge.

Symptoms of a lipoma and differences from an atheroma

A typical lipoma looks like this:

• soft and doughy to the touch, shifts slightly under the skin when pressed;
• size — from a pea to several centimeters;
• usually painless;
• grows slowly.

A lipoma can be difficult to distinguish from an atheroma, a hygroma, and lymphadenitis. An adenolipoma — a rare variant of lipoma — is also hard to distinguish from an atheroma. Therefore, the conclusion is made by a doctor after examination, and in case of doubt — after scanning.

How a lipoma is diagnosed and when to see a doctor

Most often the diagnosis is made at an appointment: the doctor, as a rule, can determine that the lump is a lipoma. If in doubt, the patient is referred for an imaging study (scan) to clarify the nature of the formation. If the nodule is removed according to indications, it may be sent to a laboratory for testing.

You should come for an examination when any lump appears on the body, and also if the nodule is painful, the skin over it is red or hot to the touch, the formation is hard and does not shift, or it increases in size. Treatment is usually not required: removal is discussed only when the lipoma grows or interferes because of its location.

A lipoma in itself is not a reason to call an ambulance; 103/112 — for signs of stroke or heart attack or severe injury.

This material is for reference: it describes general signs and does not replace consultation with a doctor, who will examine the specific formation.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer