Background: Lymphedema typically affects a whole limb. Rarely, lymphedema can present as a circumscribed plaque or an isolated skin tumor.
Objective: To describe the clinical and pathologic characteristics and etiologic factors of localized lymphedema.
Methods: Case–control study of skin biopsy and excision specimens histologically diagnosed with lymphedema and presenting as a localized skin tumor identified during a 4-year period.
Results: We identified 24 cases of localized lymphedema presenting as solitary large polyps (11), solid or papillomatous plaques (7), pendulous swellings (4), or tumors mimicking sarcoma (2). Patients were 18 females and 6 males with a mean age of 41 years (range 16–74). Anogenital involvement was most frequent (75%) – mostly vulva (58%), followed by eyelid (13%), thigh (8%) and breast (4%). Causative factors included injury due to trauma, surgery or childbirth (54%), chronic inflammatory disease (rosacea, Crohn’s disease) (8%), and bacterial cellulitis (12%). Eighty-five percent of these patients were either overweight (50%) or obese (35%). Compared with a series of 80 patients with diffuse lymphedema, localized lymphedema patients were significantly younger (41 vs. 62 years old, p = 0.0001), had no history of cancer treatment (0% vs. 18%, p = 0.03), and had an injury to the affected site (54% vs. 6%, p = 0.0001). Histologically, all cases exhibited dermal edema, fibroplasia, dilated lymphatic vessels, uniformly distributed stromal cells and varying degrees of papillated epidermal hyperplasia, inflammatory infiltrates and hyperkeratosis. Tumor size significantly and positively correlated with history of cellulitis, obesity, dense inflammatory infiltrates containing abundant plasma cells, and lymphoid follicles (p < 0.05). A history of cellulitis, morbid obesity, lymphoid follicles and follicular cysts predicted recurrent or progressive swelling despite excision (p < 0.05).
Conclusions: Localized lymphedema should be considered in the etiology of skin tumors when assessing a polyp, plaque, swelling or mass showing dermal edema, fibrosis and dilated lymphatics on biopsy. A combination of lymph stasis promoting factors (trauma, obesity, infection and/or inflammatory disorders) produces localized elephantiasis.