- See:
Soft Tissue Menu
- Discussion:
- benign tumor composed of lobules of mature fat;
- most common tumor of soft tissue;
- occurs most often in adults;
- tumor usually presents as active
stage 2 lesion, later becoming latent;
- usually it appears as soft, slowly enlarging, asymptomatic mass located superficially in subQ tissues, commonly seen in the back, buttocks, and thighs;
- it can also appear deep to the fascia, lying in fatty planes along N/V bundles;
- lipomas do not cross fascial boundries but will grow in between fascial planes;
- lipomas that arise in deep tissues may become remarkably large;
- these lesions may have a firm consistency similar to a sarcoma;
-
sub-types:
-
intra-muscular lipoma:
- these lesions can become large in size before detection;
- typically has a firm consistency which mimics sarcoma;
- often these lesions will be in close contact w/ neurovascular bundle;
-
angiolipoma:
- variant of lipoma w/ vascular component, occurs in children as a deep, subcutaneous or intramuscular soft mass;
- it is distinguished from ordinary lipoma by distinct tenderness to palpation;
- angiography is the best method for diagnosing angiolipoma;
- note that in the majority of cases multiple tumors may be present;
-
diff dx:
- Kaposi's sarcoma;
-
angiosarcoma
-
spindle cell sarcoma:
- presents as a painless nodule;
- histologically the tumor contains a mixture of fat and spindle cells;
- Diff Dx: liposarcoma: most occur proximal to the knee and elbow;
- Radiographic studies:
- crisply marginated radiolucent image;
- may show calcification in areas of necrosis and metaplastic bone or cartilage;
- MRI:
- w/ lipoma, signal intensity of lesion parallels that of subcutaneous fat on all pulse sequences (
T1 and
T2);
- Bone Scan:
- usual avascular lipoma appears avascular on bone scan;
- if bone scan is hot consider
liposarcoma;
- Treatment:
- marginal excision is successful for lipoma, and recurrences are rare;
- note that lipomas cannot be read by frozen section, and can only be interpreted by permanent sections;
Intraosseous lipomas. A clinicopathologic study of 66 cases.
Size, site and clinical incidence of lipoma. Factors in the differential diagnosis of lipoma and sarcoma.
A 20-year retrospective review of surgically treated liposarcoma at the Cleveland Clinic.
