Massive localized lymphedema with unusual presentations: report of 2 cases and review of the literature.

Massive localized lymphedema is a benign soft tissue lesion that usually presents as a large mass in morbidly obese adults. The diagnosis may be challenging as it can mimic other lesions, including well-differentiated liposarcoma. We report 2 cases of massive localized lymphedema with unusual presentation. The first case is a recurrent massive localized lymphedema in the right thigh of a 40-year-old morbidly obese woman. In addition to typical massive localized lymphedema features such as prominent edema and vascular proliferation in the adipose tissue, we observed prominent and abundant multinucleated stromal floret-like giant cells, arborizing network of capillaries, and areas of hyalinized collagen. Our second case is in a rare location (scrotum extending into penile soft tissue) in an overweight 55-year-old male. This lesion exhibits striking smooth muscle hyperplasia. Lack of staining by antibodies against murine double minute 2 protein and cyclin dependent kinase 4 and absence of high mobility group AT- hook 2 transcription factor rearrangement by fluorescence in situ hybridization support our diagnosis of massive localized lymphedema in both cases.