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%). Eigh...