What is a lipoma?
A lipoma is a non-cancerous, slow-growing tumor made of fatty tissue that develops just below the skin. They are the most common cause of the so-called "fat balls" people find on their bodies and are typically harmless. Lipomas usually appear as soft, doughy, or rubbery lumps that feel mobile when pressed with a finger. While they are most often small (less than 2 inches in diameter), they can grow larger over time.
Common characteristics of lipomas
- Location: Most frequently found on the neck, shoulders, back, abdomen, arms, and thighs.
- Texture: Soft and doughy or rubbery to the touch.
- Movement: Move easily with slight finger pressure.
- Pain: Generally painless, unless they grow large enough to press on a nerve or contain blood vessels (angiolipoma).
- Growth Rate: Slow-growing and can remain stable for years.
What are epidermoid and other types of cysts?
An epidermoid cyst is a sac-like growth under the skin, filled with keratin, a protein found in skin cells. Though sometimes incorrectly referred to as a sebaceous cyst, a true sebaceous cyst is much rarer and originates from oil-producing glands. Epidermoid cysts are also a common cause of small skin lumps and are typically benign.
Characteristics of different cysts
- Epidermoid Cysts:
- Appearance: A small, round bump under the skin, often with a tiny blackhead plugging a central opening.
- Contents: Contains a thick, cheesy, often foul-smelling substance (keratin) that may leak.
- Feel: Can feel firm or tender, especially if inflamed or infected.
- Sebaceous Cysts:
- True Origin: These are less common than epidermoid cysts and arise from the sebaceous glands.
- Contents: Contains sebum, the oily substance that lubricates skin.
How to differentiate between lipomas and cysts
Distinguishing between a lipoma and a cyst can be challenging without a doctor's evaluation, as both are common, benign skin lumps. However, some key differences can help. A lipoma is a collection of fatty tissue, making it feel soft and movable, while a cyst is a sac filled with keratin or other substances, which may make it feel firmer and potentially have a central pore.
| Feature | Lipoma | Epidermoid Cyst |
|---|---|---|
| Composition | Fatty tissue | Keratin and skin cells |
| Feel/Texture | Soft, doughy, or rubbery | Firmer, may feel tender if infected |
| Mobility | Moves easily under the skin | Less mobile, can be fixed to surrounding tissue |
| Central Pore | None | Often has a small blackhead-like plug (punctum) |
| Discharge | None | Cheesy, foul-smelling material may leak if ruptured |
| Growth Rate | Slow and steady | Can remain stable, but may grow or become inflamed |
When should you see a doctor about a skin lump?
While most skin lumps are benign, it is always recommended to have any new lump or bump checked by a healthcare professional, especially a dermatologist, to ensure it is not a more serious condition like a liposarcoma, a rare form of cancer.
Warning signs that require medical evaluation:
- Rapid Growth: The lump is growing noticeably over a few weeks.
- Pain: The lump becomes painful, especially suddenly.
- Hardness: The lump feels hard and is fixed in place, not movable under the skin.
- Skin Changes: The skin over the lump becomes red, inflamed, or there is a change in color.
- Discharge: The lump starts to bleed or seep fluid.
- Unusual Location: Lumps in areas like the breasts, testicles, or near lymph nodes warrant closer attention.
Management and treatment options
Most benign fatty lumps do not require treatment. However, if a lump is causing discomfort, growing quickly, or is a cosmetic concern, a doctor may recommend removal. Treatment options vary depending on the type of lump:
- For Lipomas: Surgical removal (excision) or liposuction are common methods.
- For Cysts: A doctor may drain an inflamed cyst, inject it with steroids to reduce swelling, or surgically remove the entire cyst sac to prevent recurrence. It's crucial not to try to pop or drain a cyst at home, as this can lead to infection.
Prevention and prognosis
There is no surefire way to prevent lipomas, as they can be inherited or linked to genetic factors. Similarly, cysts can develop from blocked pores or injuries. The most important preventative step is to be aware of your skin and monitor any new growths. The prognosis for benign lumps like lipomas and cysts is excellent, and once properly removed, they rarely return in the same spot. However, new lumps can develop elsewhere.
Importance of early diagnosis
As with many health issues, early diagnosis of a skin lump can provide peace of mind and, in the rare event of a more serious condition, lead to better outcomes. For reliable information on a wide range of dermatological issues, resources like the American Academy of Dermatology are highly recommended. Consulting a healthcare professional is always the best course of action for any concerns about a new or changing skin lump.
