Are You Confident of the Diagnosis?
What you should be alert for in the history:
Lesions are typically seen in adulthood
Characteristic findings on physical examination:
Slow growing soft subcutaneous nodule (< 5cm) most commonly on the trunk, shoulder, upper arm, and neck
Expected results of diagnostic studies
Histopathology displays normal-appearing mature adipose accumulation (Figure 1). Computed tomography (CT) scan demonstrates homogenous low-density areas; magnetic resonance imaging (MRI) yields better tissue delineation and extent of tumor, especially if there is a concern for infiltrating types. Findings include homogenous low-intensity areas with no contrast enhancement.
Epidermal inclusion cyst demonstrates an overlying punctum, less stable in size, histologically distinct. Pilar cysts are usually on scalp, presenting as marble-like nodules; histologically they are distinct as are angioleiomyomas, subcutaneous neurofibromas, subcutaneous dermatofibromas, neurilemmomas, rheumatoid nodule (associated with rheumatologic problems), pseudorheumatoid nodule/deep granulare annulare, subcutaneous sarcoidosis, and hematomas (usually associated with trauma).
Who is at Risk for Developing this Disease?
Adult; middle aged (fifth to sixth decades of life). Multiple lipomas (5% to 15%) more likely in males and can be inherited in an autosomal dominant fashion (familial multiple lipomatosis syndrome).
What is the Cause of the Disease?
— fat accumulation
Systemic Implications and Complications
Most retroperitoneal tumors are well-differentiated or de-differentiated liposarcomas. Referral to a medical center that specializes in soft tissue sarcomas is recommended.
Multiple symmetric lipomatosis (Madelung disease, Launois-Bensaude syndrome) is observed in middle-aged men, often with a history of alcoholism or liver disease and an association with glucose intolerance. Peripheral neuropathy may be associated. Screening for these associated medical problems should be undertaken.
Adiposis dolorosa (Dercum disease) presents as multiple (hyperalgesia) painful nodules more commonly in middle-aged, overweight women. Characteristically, lesions are located on the upper legs, trunk, and upper arms. Emotional and psychiatric problems are commonly associated. Patients may need to be referred for psychiatric treatment.
Congenital midline lipoma on back can be associated with spinal dysraphism such as spina bifida occulta and spinal cord abnormalities. Imaging with CT and MRI should be used to evaluate for spinal dysraphism.
Surgical: Excision; liposuction
Medical: Mesotherapy with deoxycholate +/- phosphatidylcholine. No peer-reviewed clinical trials that critically evaluate efficacy. Results in studies otherwise reveal 70% to 100% response, but many studies did not have a good way to show objective evaluation and many others did not show long-term follow-up.
Optimal Therapeutic Approach for this Disease
If treatment is desired, excision remains the gold standard (Figure 2, Figure 3, Figure 4). The infiltrating type of lipoma has a reported recurrence rate of 50%. Liposuction has been associated with higher recurrence.
Mesotherapy has been described for lipomas.
Patients should be reassured that these lesions are benign. Usually no treatment is necessary.
Biopsy or removal needs to be considered when size is greater than 5cm, tumor depth to deep fascia, tumor is relatively fast-growing, and concerning clinical features are found such as firmness or irregularity. Preoperative core needle biopsy (image-guided) will likely be needed, especially in tumors located deep in the body. It has an accuracy of 73%. Imaging (CT or MRI) may reveal heterogeneity and wider septae in cases of liposarcoma (also seen with a deep atypical lipoma).
Be aware of the association of spinal dysraphism with congenital midline lipoma. Also, consider associated systemic abnormalities associated with multiple symmetric lipomatosis.
Unusual Clinical Scenarios to Consider in Patient Management
Variants include angiolipoma, myolipoma (smooth muscle and lipoma, retroperitoneum and abdomen, more commonly in women), chondroid lipoma (rare, subcutaneous or deeper soft tissue of limb or limb girdles, 80% women), lipoblastoma/ lipoblastomatosis (< 3 years old [>90%], boy [2 to 3 times more than girl] on extremities more commonly than the neck and trunk, 14% to 25% recurrence with excision), spindle-cell/ pleomorphic lipoma, intramuscular lipoma, lipomatosis of nerve, lipoma of the tendon sheath and joint, lipoma arborescens (diffuse form of synovial lipoma; usually monoarticular and involves the knee, and is frequently associated with degenerative joint disease, rheumatoid arthritis, or prior injury—most commonly fifth to seventh decade of life), infiltrating lipomas (infiltration of a single tissue such as muscle), and hibernoma.
Frontalis-associated lipomas (of forehead): usually deep with many below the frontalis muscle or associated galea. The clinical nodule may be very firm and resemble an osteoma
Deep lipomas represent about 1% of lipomas; they are most commonly found in the chest wall and hands and feet. Most retroperitoneal tumors are well-differentiated or de-differentiated liposarcomas
Diffuse lipomatosis: diffuse overgrowth of mature adipose tissue that infiltrates multiple tissues in large body areas such as an extremity or trunk.
Bannayan-Riley-Ruvalcaba syndrome: rare autosomal dominant genodermatosis with classic triad of macrocephaly, genital lentiginosis, and intestinal polyposis. Mucocutaneous manifestations also include vascular malformations and lipomatosis.
Nasopalpebral lipoma-coloboma syndrome: extremely rare reports in literature of an autosomal dominant craniofacial dysmorphic syndrome characterized by congenital nasopalpebral lipomata, eyelid colobomata, and midfacial skeletal abnormalities such as maxillary hypoplasia.
What is the Evidence?
Pandya, KA, Radke, F. “Benign skin lesions: Lipomas, epidermal Inclusion cysts, muscle and nerve biopsies”. Surg Clin North Am. vol. 89. 2009. pp. 677-87. (Review of lipomas and epidermal inclusion cysts including workup and treatment.)
Bancroft, LW, Kransdorf, MJ, Peterson, JJ, O’Conner, MI. “Benign fatty tumors: classification, clinical course, imaging appearance, and treatment”. Skeletal Radiol. vol. 35. 2006. pp. 719-33. (Review of different fatty tumors with special discussion of imaging findings.)
Sewell, LD, Adams, DC, Marks, VJ. “Subcutaneous forehead nodules: Attention to the button osteoma and frontalis-associated ipoma”. Dermatol Surg. vol. 34. 2008. pp. 791-8. (Review of 2 causes of firm forehead nodules including treatment)
Silistreli, OK, Durmus, EU, Ulusal, BG, Oztan, Y, Gorgu, M. “What should be the treatment modality in giant cutaneous lipomas? Review of the literature and report of 4 cases”. Br J Plast Surg. vol. 58. 2005. pp. 394-8. (Case report and review of treatment options of large cutaneous lipomas)
Rotunda, AM, Kolodney, MS. “Mesotherapy and phosphatidylcholine injections: historical clarification and review”. Dermatol Surg. vol. 32. 2006. pp. 465-80. (Review of mesotherapy and phosphatidylcholine injections including review of published studies and reported outcomes)
Erkek, E, Hizel, S, Sanlý, C, Erkek, AB, Tombakoglu, M, Bozdogan, O. “Clinical and histological findings in Bannayan-Riley-Ruvalcaba syndrome”. J Am Acad Dermatol. vol. 53. 2005. pp. 639-43. (Case report and review)
Penchaszadeh, VB, Velasquez, D, Arrivillaga, R. “The nasopalpebral lipoma-coloboma syndrome: a new autosomal dominant dysplasia-malformation syndrome with congenital nasopalpebral lipomas, eyelid colobomas, telecanthus, and maxillary hypoplasia”. Am J Med Genet. vol. 11. 1982. pp. 397-410. (Authors describe first cases of this rarely reported syndrome.)
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