Juxtamalleolar Lipoma ^†

Gross and Burnett[1] in 1933 described the appearance of semifluctuant irregularly lobulated fatty masses beneath the outer malleoli as a common observance. While the literature suggests that lipomas of the feet are uncommon, the author’s experience suggests that juxtamalleolar lipomas are commonly overlooked and under diagnosed.[2-4] Lipomas around the malleoli are a common occurrence in middle-aged women. Because of their appearance during menopause, these fat deposits were once referred to as Menopausal Lipoma. This association, however, has not been proven. These fatty masses may occur either gradually or appear fairly suddenly within a year or two. These swellings often are confused with edema from congestive heart disease or ankle synovitis associated with arthritis. The lesions tend at times to be tender or painful due to compression of the sensory branch of the superficial peroneal nerve, which normally traverses these fatty masses.[5]

Case Report

A 53-year-old woman with bilateral ankle swelling presented herself with a complaint of periodic tenderness and discomfort in the area. Upon examination, firm subcutaneous masses were noted anterior and posterior to both lateral malleoli (Fig. 1 A and B). Some tenderness was present upon palpation of these masses. Magnetic resonance imaging of the area demonstrated increased signal intensity on T1-weighted spin-echo image consistent with normal fat (Fig. 2). Excision of these masses revealed lobular accumulation of normal fat (Fig. 3). Pathologic examination revealed normal fat surrounding the intermediate dorsal cutaneous branch of the superficial peroneal nerve (Fig. 4 A and B).

Figure 1A. Bilateral ankle swellings suggestive of ankle edema.

Figure 1A. Bilateral ankle swellings suggestive of ankle edema.

Figure 1B. Lesions are firm and circumscribed characteristically located anterior to the lateral malleoli.

Figure 1B. Lesions are firm and circumscribed characteristically located anterior to the lateral malleoli.

Figure 2. Magnetic resonance imaging T1-weighted spin-echo image demonstrating normal fat.

Figure 2. Magnetic resonance imaging T1-weighted spin-echo image demonstrating normal fat.

Figure 3. Large mass of normal fat removed from ankle.

Figure 3. Large mass of normal fat removed from ankle.

Figure 4A. Fat demonstrating large section of sensory nerve.

Figure 4A. Fat demonstrating large section of sensory nerve.

Figure 4B. Nerve embedded in lipoma.

Figure 4B. Nerve embedded in lipoma.