• Patients with breast cancer are at risk of developing secondary lymphedema after surgery and removal of lymph nodes or radiation therapy in the axillary region. It has been estimated that secondary lymphedema develops in 10-40% of breast cancer patients.
• Surgical removal of lymph nodes or radiation therapy for any type of cancer such as breast cancer, pelvic cancer, prostate cancer, melanoma. The risk of lymphedema increases with the number of lymph nodes removed.
• Lymph node cancer (lymphoma).
• Infection or injury that obstructs the lymphatic system.
• Chronic venous insufficiency causing venous stasis (slow venous circulation in the lower extremities).

Filariasis. A group of tropical diseases from parasites that enter enter the lymphatic system through an insect bite. The parasites can reach up to 8cm in length and often nest in the lymph nodes. This condition is commonly found in tropical areas of Southeast Asia, South America, Africa, and the Pacific Islands.