What condition is characterized by swelling due to an abnormal accumulation of lymph fluid within the tissues?

Lymphedema is specifically characterized by the abnormal accumulation of lymph fluid in the tissues, leading to swelling. This condition typically occurs due to a malfunction in the lymphatic system, which may be caused by factors such as surgery, radiation treatment, or an infection that impairs the flow of lymph. The lymphatic system's proper function is vital for draining excess fluid from tissues and maintaining fluid balance, so when it is disrupted, fluid builds up, resulting in observable swelling in the affected areas.

In contrast, edema is a broader term that refers to swelling caused by fluid retention in general, which can result from various causes, including systemic conditions like heart failure, not limited to lymphatic issues. Ascites refers specifically to fluid accumulation in the abdominal cavity, often due to liver disease or heart failure. Prolapse is a condition related to the descent of an organ from its normal position and is not associated with fluid accumulation. Therefore, lymphedema is the most accurate condition described in the question, highlighting its unique characteristics in the realm of fluid retention disorders.