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A 50-year-old woman has noticed bilateral enlargement of her lower legs and buttocks since she was in her early 30s. She states that her feet appear normal and relates a marked size discrepancy between her upper body and lower body described as "my upper half is a size 8 and my lower half is a size 20." Her legs are extremely sore at the end of the day and bruise easily. Despite weight loss and exercise her swelling persists. She has been evaluated by several physicians in the past and had multiple negative venous duplex ultrasounds. Diuretics, compression stockings, and complex decongestive lymphatic physiotherapy were also prescribed without relief. After her last physician consultation she was given a diagnosis of "lymphedema" (Figure 70-1).
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The prevalence of lipedema is not well established. In two clinics specializing in lymphology and edema, 10% to 20% of clinic patients were diagnosed with lipedema, suggesting a prevalence of 0.06% to 0.07%.1,2
A positive family history has been reported in 20% to 60% of patients diagnosed with lipedema, and current research suggests either X-linked dominant inheritance or, more likely, autosomal dominant inheritance with sex limitation.3
Lipedema almost exclusively affects females, with only rare cases reported in men.4
Onset of the disease is typically noticed between the ages of 10 and 30, but most patients present with this disease later in life or have had a substantial delay in diagnosis due to the under recognition of the condition.
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ETIOLOGY AND PATHOGENESIS
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Lipedema is a pathologic adverse deposition of fatty tissue, usually below the waist. It was first described by Dr. Edgar V. Allen and Dr. Edgar A. Hines in 1940 as a syndrome of subcutaneous symmetric deposition of fat in the buttocks and lower extremities and is often confused with obesity or lymphedema.5
Lipedema is a chronic disease of lipid metabolism resulting in the symmetrical impairment of fatty tissue distribution and storage combined with hyperplasia and/or hypertrophy of individual fat cells.6
The exact pathophysiologic cellular mechanism has not been clearly elucidated. It has been hypothesized that a correlation with an adverse hormonal axis exists due to lipedema's predilection for women as well as its onset around puberty. Other conditions of hormonal dysregulation such as cirrhosis underlie some cases, especially in men.7
Additional mechanisms thought to play a role in the pathogenesis of lipedema include increased vascular permeability, excessive lipid peroxidation, and disturbances in adipocyte metabolism and cytokine production.8
Lipedema is initially characterized by normal lymphatic function. ...