Lipoma in AdultSee also in: Oral Mucosal Lesion
Alerts and Notices
SynopsisLipomas are benign tumors of slow-growing, mature fat cells. They are the most common soft tissue tumor.
Clinically, lipomas present as soft, rubbery, freely mobile subcutaneous masses without overlying skin change. They are most often solitary but can be multiple. They can occur anywhere on the body where fat is found, with the highest predilection for the neck, trunk, extremities, buttocks, and abdominal wall; they rarely occur on the head and neck. They can be quite small (1-2 mm) to quite large (greater than 10 cm) and occasionally are multilobular, weighing as much as 1 kg. They are usually asymptomatic; however, large tumors that compress nerves or limit normal tissue movement can cause lymphedema with discomfort and pain. Tumors with a vascular component (angiolipomas) also tend to be painful; pain may be precipitated by cold. They grow slowly to a stable size and do not spontaneously regress.
Solitary idiopathic lipomas are slightly more common in women, whereas multiple lipomas are more often seen in men. These lesions commonly present between the third and seventh decade, rarely before puberty. They may grow with weight gain but do not shrink with weight loss. Since the fat in lipomas is not available for metabolism, excessive weight loss may make the lesion more prominent. Deeper lesions may become more visible on muscle contraction. Some lipomas are familial and have autosomal dominant inheritance. Malignant transformation is rare.
The etiology of lipomas continues to be investigated. An increased incidence is associated with diabetes, obesity, and hypercholesterolemia. Fat cells of lipoma reflect an increased adipocyte turnover rate along with transcriptional changes distinct from the adipose tissue hypertrophy seen in obesity. There also appears to be less adipocyte apoptosis, owing to the tumor-like growth. In one case report, growth of multiple subcutaneous tumors was associated with protease inhibitors (PI). The homology between the PI catalytic site and the proteins involved in lipid metabolism may be significant in this finding. Moreover, PIs are known to induce several effects, including hyperlipidemia, diabetes, and lipomatosis. Another hypothesis suggests that lipomas occur as a result of trauma, which may precipitate the conversion of preadipocytes to mature adipocytes secondary to inflammatory changes.
Multiple lipomas are associated with several rare syndromes:
- Diffuse lipomatosis – Characterized by the infiltration of nonencapsulated fat into multiple tissues including muscle, skin, fascia, and bone. This entity can be seen in association with tuberous sclerosis.
- Familial multiple lipomatosis – Characterized by multiple encapsulated lipomas in several family members.
- Proteus syndrome – Characterized by multiple hamartomas (including lipomas) and disproportionate overgrowth of multiple tissues.
- Hemihyperplasia / multiple lipomatosis syndrome – Characterized by multiple lipomas, asymmetric tissue overgrowth, capillary malformations, and accentuation of plantar skin creases.
- Benign symmetric lipomatosis (Madelung disease) – Characterized by symmetric fat deposits around and above the shoulders associated with alcohol use disorder.
- Adiposis dolorosa (Dercum disease) – Characterized by multiple painful lipomas in postmenopausal women associated with weakness and depression.
- Gardner syndrome – Characterized by multiple lipomas, colon polyposis, odontomas, epidermoid cysts, osteomas, leiomyomas, desmoid fibromatosis, and hypertrophy of the retinal pigment epithelium.
- Bannayan-Riley-Ruvalcaba syndrome – Characterized by multiple lipomas, macrocephaly, intestinal polyposis, lentigines of the penis, and hemangiomas.
D17.9 – Benign lipomatous neoplasm, unspecified
93163002 – Lipoma
Differential Diagnosis & Pitfalls
- There is no overlying skin change, nor are there ostia or dilated pores as would be seen in an epidermoid cyst. Cysts are usually firmer and more superficial.
- Metastatic malignancy is usually much firmer to the touch.
- Dermoid cyst
- Hibernomas (brown fat) – These are often large, persistent lipomatous lesions on the neck, back, or axilla. Biopsy is necessary for definitive diagnosis.
- Abscess – One would expect to see accompanying erythema and induration.
- Blue rubber bleb nevus syndrome
- Glomus tumor
Drug Reaction DataBelow is a list of drugs with literature evidence indicating an adverse association with this diagnosis. The list is continually updated through ongoing research and new medication approvals. Click on Citations to sort by number of citations or click on Medication to sort the medications alphabetically.
Patient Information for Lipoma in Adult
OverviewA lipoma is a soft lump just under your skin made of fat cells. It grows slowly between the skin and muscle. It is not cancerous. Lipomas can grow anywhere on your body where there are fat cells.
Who’s At RiskLipomas tend to run in families. If someone you're related to has lipomas, you have a greater chance of lipoma growth. Lipomas are rare in children. They usually begin growing in middle age.
The cause of lipomas is unknown. However, obese individuals and people with diseases such as diabetes, high blood cholesterol, and some inherited disorders may be at higher risk of developing lipomas.
Signs & SymptomsLipomas feel doughy and do not hurt to touch. A lipoma is not hard and you may be able to move it with your fingers. There is no color change to the skin.
The size and body location can vary, but the neck, shoulders, chest, thighs, arms, and back are common locations. There may be several lipomas growing at the same time, but usually people develop one or two at once.
Self-Care GuidelinesLipomas are not harmful and are not signs of cancer. They do not require treatment.
When to Seek Medical CareSometimes a lipoma may grow in a location on your body that makes you uncomfortable, such as on your face or near a bundle of nerves. A medical professional can remove a lipoma if its growth is bothering you.
If the lipoma is growing very fast, does not move to your touch, seems deeper than just under your skin, or causes you pain, see your doctor to make sure you actually have a lipoma.
TreatmentsYour doctor may perform a biopsy to confirm that you have a lipoma. A sample of the fatty tissue will be analyzed by a lab or your physician will look at the sample under a microscope to make sure it is only fatty tissue.
If your lipoma is uncomfortable, you and your doctor may decide to remove it. A very small incision is made over the lipoma, and the entire lipoma can be removed through the small opening.
If the lipoma is large, it can be removed with liposuction to prevent a scar. A needle and syringe are used to remove the fatty tissue.
Lipoma in AdultSee also in: Oral Mucosal Lesion