AUTHOR AND EDITOR INFORMATION

Section 1 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Miscellaneous
• Multimedia
• References

INTRODUCTION

Section 2 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Miscellaneous
• Multimedia
• References

Background

Lipomas are benign tumors composed of mature fat cells. They are the most common benign mesenchymal tumor. Lipomas are found in the subcutaneous tissues and, less commonly, in internal organs. They usually present with little difficulty in diagnosis or morbidity. Lipomas typically develop as discrete rubbery masses in the subcutaneous tissues of the trunk and proximal extremity. They usually are a few centimeters in size and can be removed by surgical excision or liposuction.

The eMedicine general surgery article Lipomas may be of interest, as may the Medscape Dermatologic Surgery Resource Center.

Pathophysiology

Lipomas differ biochemically from normal fat by demonstrating increased levels of lipoprotein lipase and by the presence of a larger number of precursor cells.

Approximately 60% of solitary cutaneous lipomas display clonal alterations. The most common alteration involves a breakpoint on bands 12q13-15. Karyotype aberrations also have been noted on arms 6p and 13q. Multiple lipomas do not display these alterations.

Frequency

International

In one study in a Scandinavian population, 43% of benign mesenchymal tumors were lipomas.

Mortality/Morbidity

No fatalities are reported with cutaneous lipomas. Mild tenderness occasionally is associated with the tumors. Angiolipomas often are tender.

Sex

Solitary lipomas are seen predominately in women. Multiple lipomas occur more frequently in men.

Age

Lipomas can occur at any age; however, they usually arise in early adulthood and are rare in children and infants.

CLINICAL

Section 3 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Miscellaneous
• Multimedia
• References

History

Patients usually give a history of a slowly growing lesion present for several years and usually do not complain of discomfort. Lipomas are classified in the following categories:

• Solitary lipomas (most common)
• • Most solitary lipomas are superficial and small.
  • Solitary lipomas may develop with weight gain but usually do not shrink after weight loss.
• Diffuse congenital lipomatosis
• • Diffuse poorly demarcated lipomas localized primarily on the trunk characterize this type (see Media File 1).
  • Tumors often infiltrate through muscle fibers, making them resistant to surgical removal. These tumors are composed of immature fat cells.
• Benign symmetric lipomatosis (Madelung disease)
• • Madelung described the condition in 1888.
  • Lipomas of the head, neck, shoulders, and proximal upper extremities characterize this condition.
  • Men are affected 4 times as often as women.
  • The patient's history often includes excessive alcohol consumption or diabetes.
  • Other conditions associated with Madelung disease include malignant tumors of the upper airways, hyperuricemia, obesity, renal tubular acidosis, peripheral neuropathy, and liver disease.
• Familial multiple lipomatosis
• • This clinical entity is characterized by few-to-many, small, well-demarcated, encapsulated lipomas that commonly involve the extremities.
  • Typically, this form appears during or soon after adolescence.
  • The neck and shoulders usually are spared (unlike benign symmetric lipomatosis).
  • A family history of multiple lipomas usually exists, and an autosomal dominant mode of inheritance is found.
• Dercum disease (adiposis dolorosa)
• • Painful lipomas are the hallmark of this rare condition.
  • Lipomas typically occur on the extremities of obese postmenopausal women.
  • Alcoholism, emotional instability, and depression commonly are associated with Dercum disease.
• Angiolipomas
• • Typically, these tender, soft, subcutaneous nodules are present in adolescence.
  • Tumors frequently are multilobulated and are somewhat firmer than ordinary lipomas.
  • The associated pain is vague and may be spontaneous or caused by pressure.
• Hibernomas
• • Tumors are solitary well-circumscribed nodules that typically are asymptomatic.
  • Usually, tumors are located in the interscapular region, axillae, neck, or mediastinum.
  • Histologically, hibernomas are composed of embryonic brown lipoblasts termed mulberry cells because of their appearance.

Physical

• Lipomas present as subcutaneous nodules of 2-10 cm.
• Lipomas often are lobulated.
• Consistency is rubbery.
• Skin overlying the lesion is normal and is not connected to the tumor.
• Neck, back, and proximal extremities are affected most commonly.

DIFFERENTIALS

Section 4 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Miscellaneous
• Multimedia
• References

Other Problems to be Considered

Hibernomas
Lipoblastomas
Liposarcomas
Neurofibromas
Epidermoid cysts (occasionally)

Benign symmetric lipomatosis
Obesity
Sialadenitis
Goiter
Lymphatic tumor

Angiolipomas
Dermatofibromas (occasionally)
Blue rubber bleb nevus, eccrine spiradenoma, neuroma, neurofibromas, glomus tumors, granular cell tumors, angiolipomas, leiomyoma; also termed BENGAL

WORKUP

Section 5 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Miscellaneous
• Multimedia
• References

Imaging Studies

• CT scanning is indicated in suspected liposarcoma. CT scanning is useful for distinguishing between lipomas and liposarcomas.¹

Procedures

• Fine-needle aspiration is indicated when the diagnosis of liposarcoma is suspected.

Histologic Findings

Lipomas histologically resemble normal fat. When completely excised, a thin fibrous capsule surrounding the aggregate of adipocytes may be seen. Without a clinical or gross description, it often is impossible to distinguish between tumor cells and mature adipocytes.

Lipomas differ biochemically from normal mature fat. Lipomas have increased levels of lipoprotein lipase.

TREATMENT

Section 6 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Miscellaneous
• Multimedia
• References

Medical Care

Surgical techniques typically are used; however, Dercum disease also has been treated medically using intravenous infusions of lidocaine,² steroids, and analgesic medications. Topical EMLA (eutectic mixture of lidocaine and prilocaine in a ratio of 1:1 by weight) also has been used for Dercum disease.³ Intravenous use of lidocaine can be effective for Dercum disease; however, adverse effects typically outweigh benefits.

Mesotherapy^{4, 5} is a treatment for body conturing that has been used for many years in Europe. Mesotherapy involves a series of injections containing many different ingredients, including vasodilators, nonsteroidal anti-inflammatory drugs, enzymes, and hormones. A common chemical used is lecithin (phosphatidylcholine isoproterenol), a lipolytic agent. However, a recent study has shown that when lecithin solubilized with deoxycholate was used to treat subcutaneous lipomas, the active ingredient was actually the deoxycholate rather than the phosphatidalcholine.⁶ This study suggested that low-concentration deoxycholate may be a safe and effective treatment for small collections of fat. While more study is needed, mesotherapy may one day be the treatment of choice for certain lipomas.

Surgical Care

Multiple surgical techniques can treat lipomas. Carefully evaluate infiltrating lipomas when considering excision, since they can develop in intramuscular or intermuscular locations. They also can infiltrate into tendon, bone, and nerve, thus requiring careful microdissection to preserve important structures.

• Simple surgical excision
• • Mark the palpable borders on the skin before infiltrating with anesthesia (see Media File 2).
  • Incise skin down to the lipoma capsule, and dissect to free the mass from the surrounding tissue.
  • After obtaining hemostasis, close the dead space using buried absorbable sutures.
  • Remove excess skin, close the wound, and apply a pressure dressing for 24 hours to prevent hematoma or seroma formation.
• Squeeze technique (for small superficial lipomas)
• • Make a stab incision, which can be as small as one fourth of the lipoma's diameter.
  • Express the lipoma by putting pressure on the lateral aspects of the incision (see Media File 3).
  • Gentle dissection with a curette or blunt undermining scissors also may be required.
• Liposuction^{7, 8, 9}
• • Liposuction has been shown to be an excellent method for removing lipomas, angiolipomas, the lipomas of Madelung disease, and adiposis dolorosa.
  • The advantages of liposuction include reduced operative time and smaller incisions.

MISCELLANEOUS

Section 7 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Miscellaneous
• Multimedia
• References

Medical/Legal Pitfalls

• Failure to distinguish benign lipoma from liposarcoma, which is the most common soft-tissue malignancy in adults. Liposarcomas rarely arise in a preexisting lipoma and usually are found in middle-aged or older adults. Liposarcomas can be rapidly growing nonmobile masses that can cause pain resulting from the compression of nerves. The skin above them can become ulcerated. If a liposarcoma is suspected, perform a fine-needle aspiration to confirm the diagnosis.

MULTIMEDIA

Section 8 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Miscellaneous
• Multimedia
• References

Media file 1:  A 43-year-old white man with a 3- to 4-year history of a slow-growing asymptomatic growth on his right shoulder.
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Media type:  Photo

Media file 2:  A 43-year-old man with a slow-growing asymptomatic growth (same patient as in Image 1).
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Media type:  Photo

Media file 3:  Surgical excision of a 6-cm lipoma on the back of a 54-year-old man using the squeeze technique.
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Media type:  Photo

REFERENCES

Section 9 of 9

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Miscellaneous
• Multimedia
• References

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2. Juhlin L. Long-standing pain relief of adiposis dolorosa (Dercum's disease) after intravenous infusion of lidocaine. J Am Acad Dermatol. Aug 1986;15(2 Pt 2):383-5. [Medline].
3. Reggiani M, Errani A, Staffa M, Schianchi S. Is EMLA effective in Dercum's disease?. Acta Derm Venereol. Mar 1996;76(2):170-1. [Medline].
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5. Rohrich RJ. Mesotherapy: what is it? Does it work?. Plast Reconstr Surg. Apr 15 2005;115(5):1425. [Medline].
6. Rotunda AM, Ablon G, Kolodney MS. Lipomas treated with subcutaneous deoxycholate injections. J Am Acad Dermatol. Dec 2005;53(6):973-8. [Medline].
7. Berntorp E, Berntorp K, Brorson H, Frick K. Liposuction in Dercum's disease: impact on haemostatic factors associated with cardiovascular disease and insulin sensitivity. J Intern Med. Mar 1998;243(3):197-201. [Medline].
8. DeFranzo AJ, Hall JH Jr, Herring SM. Adiposis dolorosa (Dercum's disease): liposuction as an effective form of treatment. Plast Reconstr Surg. Feb 1990;85(2):289-92. [Medline].
9. Rubenstein R, Roenigk HH Jr, Garden JM, Goldberg NS, Pinski JB. Liposuction for lipomas. J Dermatol Surg Oncol. Nov 1985;11(11):1070-4. [Medline].
10. Bonatus TJ, Alexander AH. Dercum's disease (adiposis dolorosa). A case report and review of the literature. Clin Orthop Relat Res. Apr 1986;251-3. [Medline].
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13. Gonciarz Z, Mazur W, Hartleb J, Machniak M, Bednarek I, Mazurek U, et al. Interferon alfa-2b induced long-term relief of pain in two patients with adiposis dolorosa and chronic hepatitis C. J Hepatol. Dec 1997;27(6):1141. [Medline].
14. Held JL, Andrew JA, Kohn SR. Surgical amelioration of Dercum's disease: a report and review. J Dermatol Surg Oncol. Dec 1989;15(12):1294-6. [Medline].
15. Myhre-Jensen O. A consecutive 7-year series of 1331 benign soft tissue tumours. Clinicopathologic data. Comparison with sarcomas. Acta Orthop Scand. Jun 1981;52(3):287-93. [Medline].
16. Ruzicka T, Vieluf D, Landthaler M, Braun-Falco O. Benign symmetric lipomatosis Launois-Bensaude. Report of ten cases and review of the literature. J Am Acad Dermatol. Oct 1987;17(4):663-74. [Medline].
17. Rydholm A, Berg NO. Size, site and clinical incidence of lipoma. Factors in the differential diagnosis of lipoma and sarcoma. Acta Orthop Scand. Dec 1983;54(6):929-34. [Medline].
18. Solvonuk PF, Taylor GP, Hancock R, Wood WS, Frohlich J. Correlation of morphologic and biochemical observations in human lipomas. Lab Invest. Oct 1984;51(4):469-74. [Medline].
19. Tallini G, Dal Cin P, Rhoden KJ, Chiapetta G, Manfioletti G, Giancotti V, et al. Expression of HMGI-C and HMGI(Y) in ordinary lipoma and atypical lipomatous tumors: immunohistochemical reactivity correlates with karyotypic alterations. Am J Pathol. Jul 1997;151(1):37-43. [Medline].
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Article Last Updated: May 8, 2008