What is Lipoma?
Lipomas are non-cancerous lumps of fat cells that are typically soft and painless. They are commonly found on the body’s trunk but can appear anywhere fat cells exist. The size of lipomas varies but they often range between 1 to more than 10 cm. Lipomas belong to a group called mesenchymal tumors, which originate from the body’s connective tissues.
There are different types of lipomas based on their appearance under a microscope. In some cases, an individual might have multiple lipomas, which may indicate different kinds of syndromes or diseases. Lipomas are usually situated beneath the skin, in the fatty layer known as the subcutaneous plane. However, sometimes they can be found in the fascia, a band of connective tissue beneath the skin, or even deeper within the muscles.
What Causes Lipoma?
Lipomas are the most common kind of tumors that form in the connective tissue of your body. They can pop up in about 1 in 1,000 people at some point in their lives. Most often, you’ll find a lipoma on the trunk of the body or on the upper arms, but they can show up anywhere you have fat cells.
Unfortunately, we’re not too sure what causes lipomas. Some suggest that injuries might lead to their formation, with the idea being that any damage could make your body produce certain proteins that might turn pre-fat cells into mature ones.
Only a small number of patients, around 2-3%, might have a genetic link to lipomas. Some of these patients have multiple lipomas that run in the family. In some cases, researchers have found a link to a specific gene on chromosome 12 for solitary lipomas, where a mutation in the HMGA2-LPP fusion gene is present. Certain genetic disorders also have lipomas as one of their symptoms.
Lastly, it’s worth noting that people who are obese, have high levels of fat in the blood, or have diabetes, may have a higher chance of developing lipomas.
Risk Factors and Frequency for Lipoma
Lipomas, which are a type of tumor, occur slightly more often in men than women. They can happen at any age but are most commonly found in people between the ages of 40 and 60. Even though lipomas are one of the most common types of tumors, there isn’t a lot of data available on how often they occur.
Signs and Symptoms of Lipoma
Lipomas are types of lumps that usually appear under the skin as soft, painless, and moveable nodules. You won’t see any changes in your skin above them. They are generally slow to grow and can reach a stable size. On rare occasions, they can grow larger than 10 centimeters and this is when they’re called “giant lipomas”. You can find them anywhere on your body but they’re usually found in areas with more fat like the torso, neck, forearms, and top parts of your arms and legs. It’s not common to have them in your hands or feet.
Some people might have multiple lipomas which account for 5 to 10% of all people with lipomas. These are often related to genetic disorders like familial lipomatosis or other genetic conditions. Lipomas can also be caused by certain medications used to manage HIV, specifically, protease inhibitors. That’s why it’s important for doctors to know your medical history and all the medication you are on.
The signs and symptoms of lipomas vary because they could differ based on their location and size. Their effects include:
- Respiratory issues related to breathing tube (bronchial) obstruction
- Problems with swallowing (dysphagia), vomiting, and reflux due to lipomas in the food pipe (esophagus)
- Presence of yellow masses in the heart (cardiac lipomas)
Lastly, lipomas can show up in many different places in or on your body, including in the skin, under the skin, between muscles, within muscles, in synovial tissues (tissues around joints), in bones, in the nervous system, or in the back of the stomach area (retroperitoneal sites).
Testing for Lipoma
Common lipomas, or benign fatty tumors, are usually diagnosed by doctors through a physical examination, and then sent to a lab for further examination after they are surgically removed. If your lipoma is unusually large (over 10 centimeters), is growing quickly, causes pain, is hard to move or is in deep tissues like the thigh or behind the abdominal cavity, your doctor might want to take images with an ultrasound, MRI, or CT scan before performing surgery.
Generally, if your lipoma is just beneath the skin, you probably don’t need any imaging studies. However, if the lipoma is in your gastrointestinal (GI) tract, which includes your stomach and intestines, it might show up on GI contrast studies. This involves swallowing or injecting a substance that helps to make certain areas of your body show up better on the radiograph. If your lipoma is in an unusual location, you might also need an ultrasound, MRI, or CT scan to get a better look at it.
Radiolucent means that the tumor allows X-rays or other forms of radiation to pass through. Although radiography, or X-ray imaging, can potentially diagnose a lipoma, it is generally only used when a doctor is not certain about what’s causing your symptoms.
Treatment Options for Lipoma
Many people seek treatment for lipomas, which are non-cancerous lumps under the skin, mainly for cosmetic reasons. Lipomas don’t tend to go away on their own, and they might appear more prominent if a person loses a significant amount of weight, as normal fat might reduce faster than the lipoma.
In many cases, if the lipoma isn’t causing any other issues, doctors may suggest simply keeping an eye on it. The decision to remove a lipoma depends on several factors such as the size of the lump, where it’s located on the body, whether it’s causing discomfort or pain, and the overall health of the patient.
If a person chooses to have a lipoma removed, the most common method is surgical excision, or cutting it out. For large lipomas, liposuction might be used as an alternative. Liposuction is a procedure usually used to remove fat deposits in the body.
For lipomas that occur in the gastrointestinal tract (the tract that runs from your mouth to your anus) methods like endoscopy and colonoscopy could be used for treatment. An endoscopy involves inserting a long, flexible tube directly into the body, usually through the mouth or rectum, to examine an internal organ or tissue in detail. A colonoscopy is a specific type of endoscopy that examines the colon. However, removing lipomas this way can come with a higher risk of damaging the colon.
When a lipoma is surgically removed, it’s often recommended to remove its entire casing to prevent it from coming back. Intracardiac lipomas, which are lipomas that occur inside the heart, need a thorough removal. Since subcutaneous lipomas (those located underneath the skin) are usually removed for looks, surgeons will aim for a neat scar. This often involves making an incision over the lump along natural skin lines.
In some rare cases, lipomas in the intestine can cause blockage or bleeding. When it’s not clear what the mass in the intestine is, it might also need to be removed. If lipomas are located in the esophagus (the tube that connects your mouth and stomach) and cannot be removed with an endoscope, they may have to be removed surgically. The surgical removal could be performed either through the natural opening in the body or by making an incision in the chest.
What else can Lipoma be?
When diagnosing a lipoma, doctors consider the possibility of other related conditions, such as:
- Epidermoid cysts, which often have a visible opening on their surface, but may still be confused with lipomas when this isn’t present.
- Hibernomas, uncommon and slow-growing lumps of brown fat, usually located between the shoulder blades or in the chest cavity.
- Angiolipomas, that cause pain, are usually smaller than 2 centimeters, and commonly appear on the forearm of young people.
- Angiomyolipomas, more often found in locations such as the fingers or toes, particularly in adult men.
- Liposarcomas, primarily occur as deep-seated tumors in the abdominal cavity or on the thighs.
Having multiple lipomas can also indicate various syndromes, including:
- Proteus syndrome, which also includes features such as skin growths, blood vessel cluster growths, and bone overgrowth, among others. This syndrome is often triggered by certain gene mutations.
- Dercum disease, observed mainly among women after menopause, includes painful lipomas and often involves nerve sensations in the skin over the lipomas. There can also be associated mental health issues.
- Familial multiple lipomatosis, generally emerges in a person’s thirties, with hundreds of lipomas developing.
Other conditions involving lipomas include benign symmetric lipomatosis, also known as Madelung disease, which tends to affect men with a drinking problem, with lipoma growths predominantly around the head, neck, and shoulders. Gardner syndrome, due to certain gene mutations, where patients also develop gastrointestinal cancers and have several other linked symptoms.
Lastly, multiple endocrine neoplasia, Cowden syndrome, and Bannayan-Riley-Ruvalcaba syndrome are each characterized by several tumor types, including lipomas, and other specific symptoms.
What to expect with Lipoma
The outlook is typically very good for benign lipomas, which are non-cancerous fatty lumps. It’s not common for them to come back after removal, but if the surgery didn’t get every part of the lipoma, there might be a chance of recurrence.
Possible Complications When Diagnosed with Lipoma
Gastrointestinal lipomas, which are fat tissue growths in the digestive system, can sometimes lead to blockages and bleeding because they can cause ulcers.
Cardiac lipomas, on the other hand, are similar growths in the heart. These could potentially cause a blockage in the blood flow (known as an embolism) if they interfere with the structure of the heart chambers.
In rare cases, local lipomas (those growing in certain specific areas) might press on nerves, leading to nerve compression. This can happen when these lipomas grow large enough to squeeze the nearby nerves and structures.
However, most lipomas are harmless and usually do not come back after they undergone surgical removal.
To reduce the chance of these lipomas growing back, it’s generally recommended to not just remove the lipoma but also its surrounding capsule during the surgical procedure.
Take note of these potential problems lipomas can cause:
- Blockages caused by gastrointestinal lipomas
- Bleeding due to ulceration from gastrointestinal lipomas
- Embolism caused by cardiac lipomas interfering with heart structures
- Nerve compression from local lipomas
But remember, the majority of lipomas are harmless and do not grow back after surgical removal.
