Lymphatic obstruction is a blockage of the lymph nodes -- vessels that drain fluid from tissues throughout the body and allow immune cells to travel where they are needed.

Lymphatic obstruction is also called lymphedema, which means swelling of the lymph passages. Lymph nodes may be enlarged for any reason.

There are many causes of lymphatic obstruction, including:

• Infections with parasites such as filariasis
• Injury (trauma)
• Radiation therapy
• Skin infections such as cellulitis (more common in obese patients)
• Surgery
• Tumors

In Western societies, one of the most common causes of lymphedema is removal of the breast (mastectomy) and underarm lymph tissue for breast cancer. This can cause lymphedema of the arm in 10% - 15% of patients. This occurs because the lymphatic drainage of the arm passes through the armpit (axilla), and tissue in the axilla is removed during mastectomy.

Rare forms of lymphedema that are present from birth (congenital) may result from problems in the development of the lymphatic vessels.