๐ ็ธฝ็ฎ้ ๏ฝ ๐ ่ฑๆๅๆ๏ผๆฌ็ฏ๏ผ ๏ฝ ๐ ๅฎๆด็ฟป่ญฏ ๏ฝ โญ ็ฒพ่ฏ็ญ่จ
Massive localized lymphedema
Massive localized lymphedema
Clinical features Massive localized lymphedema is a distinctive soft tissue lesion that arises as a complication of morbid obesity and can be confused with a neoplasm, mainly a well-differentiated liposarcoma.1โ15 Patients are grossly obese, with some predilection for females in the fifth decade of life and present with a unilateral, or rarely bilateral, large mass with predilection for the inner aspect of the proximal limbs. In some cases, multifocal presentation is seen.13 Involvement of other areas in the limbs, scrotum, suprapubic region and rarely perianal area and flank has also been reported.13 Lesions are long-standing, asymptomatic, ill-defined, can measure more than 50 cm, weight more than 7 kilograms and may be recurrent. The overlying skin can show a cobblestone or a verrucous appearance.2,15 The clinical diagnosis is usually that of a lipoma or recurrent cellulitis. Cases of cutaneous angiosarcoma arising in massive localized lymphedema have been documented.16 This might be similar to the Stewart-Treves syndrome where angiosarcoma arising in the setting of lymphedema, particularly secondary to breast axillary node dissection.
Pathogenesis and histologic features The lesion develops as a result of localized chronic lymphedema secondary to gross obesity. The latter is complicated in some patients by other causes of chronic lymphedema including surgery and trauma. An association with hypothyroidism has been reported.3
Histologically, fat lobules are separated by thick fibrous and edematous septa with elongated fibroblasts. Groups of capillaries are identified at the interface between adipose tissue and the septa. Dystrophic calcifications mimicking atypical nulcei are identified in some cases and this change may raise the possibility of a liposarcoma.13 Additional rare features include metaplastic bone formation and multinucleated cells.13
Differential diagnosis The main differential diagnosis is with sclerosing atypical lipomatous tumor. In the latter, there is cytologic atypia of adipocytes, and clusters of capillaries in the interface between adipose tissue and sclerosed septa are not usually present.