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).
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.
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. However, as the disease progresses, some patients can develop lymphatic dysfunction and secondary lymphedema, a condition known as lipolymphedema. The majority of the patients with lipolymphedema are obese.
Lipedema often runs a slow, progressive course over decades, but disease progression into lipolymphedema can accelerate suddenly.9 Table 70-1 outlines a staging system to categorize disease progression.10
| Stage | Characteristics |
|---|---|
| I | The skin is still soft and regular, but nodular changes can be felt upon palpation. There are no color changes in the skin, and the subcutaneous tissues have a spongy feel, like a soft rubber doll. Tissue hyperesthesia may develop. |
| II | The subcutaneous tissue becomes tougher and nodular. Large fatty lobules begin to form on the medial, distal, and proximal thigh and the medial and lateral ankles just above the ankle bones. The skin may have a “cottage-cheese” or “mattress” appearance. The individual may report increased hypersensitivity over the skin area. Secondary lymphedema may develop with increased leg edema, color changes, and skin fibrosis. |
| III | Bulging protrusions of fat occur on the thighs and knees that can interfere with normal gait. The patient may transition into lipolymphedema with increasing lymphatic obstruction, progressive swelling, (sub) cutaneous fibrosis, and/or weeping skin erosions. The incidence of cellulitis is increased. |
The diagnosis of lipedema is a clinical one. Diagnostic tests are unhelpful but are sometimes used to identify associated conditions such as lymphedema or venous insufficiency.
The typical presentation of lipedema is one of symmetrical bilateral enlargement of the buttocks and lower extremities with sparing of the feet.7
Involvement of the arms is less common but not rare. Most patients have a normal appearance from the waist up or a marked mismatch in fat deposition from the upper to lower body (Figure 70-2).
Losing weight (including gastric bypass surgery) is usually not successful in reducing the size of the legs.
The subcutaneous and adipose tissue is a source of persistent aching and tenderness, which is the genesis for the clinical synonym, the painful fat syndrome.11
Patients with primary lipedema can have mild orthostatic edema, especially in warm weather. However, this superimposed edema is minimal and the overall size of the extremity is fixed and not alleviated by leg elevation and compression therapy.
In contrast to patients with lymphedema, lipedema patients have a low incidence of cellulitis and other skin infections.
FIGURE 70-2
Classic representation of the truncal–lower extremity mismatch that exemplifies lipedema.
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