Massive localized lymphedema (MLL) is an area of skin and subcutaneous overgrowth associated with obesity. The purpose of this study was to determine whether MLL results from obesity-induced lymphedema (OIL) and to characterize the prevalence and risk factors for the condition.

Patients evaluated in our Lymphedema Program between 2009 and 2016 were reviewed for obese individuals (BMI ≥30 kg/m²) who had lower-extremity lymphatic function evaluated by lymphoscintigraphy. Candidate variables included age, sex, BMI, duration of lymphedema, infection history, and lymphoscintigraphy findings. A possible association between candidate variables and presence of MLL was determined using multivariable logistic regression. Optimal cutoff for BMI in predicting MLL was identified by receiver operating characteristic curve analysis.

Eighty-two patients were included in the study population. In patients with MLL (n = 17), all had OIL and none had primary or secondary lymphedema (median BMI 66 kg/m²; interquartile range 62 to 78). Massive localized lymphedema involved the thigh (n = 16; bilateral = 10, unilateral = 6), genitalia (n = 3), and suprapubic area (n = 2). Control patients without MLL (n = 65) had primary (46%), secondary (37%), or obesity-induced (17%) lymphatic dysfunction (median BMI 36 kg/m²; interquartile range 32 to 45). Logistic regression indicated a significant relationship between BMI and MLL condition; patients with a BMI >56 kg/m² had a 213-times greater odds of MLL developing vs patients with BMI ≤56 kg/m² (p < 0.0001). Age, sex, duration of obesity, and infection history were not associated with development of MLL (all p > 0.2).

Massive localized lymphedema is a consequence of OIL and affects approximately 60% of obese patients with lower-extremity dysfunction; a BMI >56 kg/m² significantly increases the risk. Obese individuals should be referred to a bariatric weight-loss center before their BMI reaches a threshold for OIL and MLL to develop.