What is lipoma?
Lipomas (or lipomata) are the most common benign soft-tissue tumor mainly composed of benign fatty cells. Lipomas are benign, slow-growing, fatty tumors forming soft, lobulated masses enclosed by a thin fibrous capsule. Subcutaneous (below skin surface) lipoma is the most common soft tissue tumor. Lipomas rarely undergo malignant / cancerous change, forming liposarcoma.
Cause
The cause of lipoma is unknown. Lipomas may be associated with a family history of lipomas, obesity, lack of exercise, or mild genetic mutations.
Symptoms
Lipomas present as soft masses below the skin, and they usually situate in the subcutaneous plane between the skin and muscle. The skin above the lipomas is usually normal. Lipomas does not cause pain, but it will slowly grow. Their shape can be round, oval or lobulated. Lipomas are usually soft with the characteristic of being easily deformed, sliding slightly below the skin, and not attached to the overlying skin or muscle. A characteristic "slippage sign" may be elicited by gently sliding a finger tangentially towards the edge of the lipoma. The lipoma will be felt slipping under and away from the finger. Lipomas usually will not cause inflammation, infection, abscess or skin necrosis.
Large lipoma may compress surrounding tissue, such as causing subcutaneous fat atrophy or muscle atrophy.
Lipomas are easily noticeable on the limbs, head and neck and affect appearance. Lipomas in the neck, shoulders, trunk and extremities can cause discomfort during daily activities or sports.
Treatment
Indications for lipomas surgery are:
- Cosmetic reasons
- Symptomatic
- Large size (e.g., >5cm)
- Suspicious of malignancy, particularly when liposarcomas are suspected
Complete surgical excision with the capsule is essential to prevent local recurrence. Lipomas can be lobulated, and it is essential that all lobules be removed. Otherwise, local recurrence can happen.
Traditional Lipoma Excision Surgery
Traditional lipoma excision surgery involves an incision slightly larger than the lipoma, excision of the lipoma, control of bleeding, and wound closure with several interrupted sutures.
Minimal Incision Surgery
Currently, minimal incision surgery and minimally invasive surgery are indicated for most subcutaneous lipomas. These can be done under local anesthesia, general anesthesia, or regional anesthesia (e.g., spinal anesthesia).
Minimal Incision Surgery
The principle is to use the smallest incision to remove the lipoma. Before small incision surgery, surgeons will select the natural skin crease with the least tension for the incision. This will make the future wound heal with good cosmesis. After a minimal size skin incision, the skin flap is raised around the incision. The wound can move around to allow dissection of the lipoma from the surrounding tissue. The lipoma is removed, and the bleeding is stopped. The skin wound is then sutured. The surgeons usually inject long-acting local anesthetic into the wound to minimize postoperative wound pain.
Minimal Invasive Surgery
Through small keyhole-size incisions, advanced endoscopy and surgical instruments are placed around the lipoma. The lipoma is dissected from the surrounding tissue. The lipoma is removed, and the bleeding is controlled. Finally, the skin wound is sutured. MIS allows the incision to be placed in an inconspicuous location. For example, an axillary incision that lifts the flap and allows the wound to move around can be used to remove lipomas from the back or the chest; an above hairline incision that allows the forehead lipoma to be removed. Doctors inject long-acting local anesthetic into the wound to minimize postoperative wound pain.
Liposuction
Liposuction allows removal of the lipomas through very small incisions. The locations of the incision wound can be remote from the actual lipomas. As there is a small chance of residual lipoma cells after liposuction, it may cause future lipoma recurrence. Therefore, only a few patients and doctors prefer liposuction for lipomas.
Anesthesia
These surgeries can be performed under local, general, or spinal (regional) anesthesia.
Frequently Asked Questions
Q: Is lipoma a cancer?
A: No. Nearly all of the lipomas are benign. Liposarcoma is a fat cell cancer and it occurs rarely.
Q: Is it necessary to remove all lipomas?
A: No. You should consider surgery if you have lipomas with the following indications for surgery: poor cosmesis, symptomatic, >5cm size, or suspicious of cancer.
Q: How to differentiate lipomas from epidermal cysts?
A: They can be differentiated by their skin attachment and presence of slippage sign.
| Lipomas | Epidermal cysts | |
|---|---|---|
| Attached to skin | No | Yes |
| Slippage sign | Yes | No |
