What the Heck is Lymphedema?

The body has tons of lymph nodes, and as I understand it, they are responsible for filtering out a lot of junk.  The lymph system circulates throughout the body, eventually taking all the junk out up to the heart level and out of the body with the rest of its waste. This explanation probably wouldn't pass a medical test, but it's how I can understand it!  So, for some reason, with lymphedema, the lymph system doesn't work correctly.  Lots of people, especially women with breast cancer, get lymphedema after surgery taking out lymph nodes.  It can affect any limb.  For some people, particularly girls around the age of puberty, lymphedema just appears.  So that's the type Mary Alice has - primary lymphedema.  In her case the lymph nodes in her right groin aren't functioning properly, or there aren't enough to do the job.  She was probably born that way.  She's our kid that has had some weird childhood medical things (toddler anemia, eczema, asthma-like wheezing) so maybe it's all related?  With lymphedema, the lymph fluid just accumulates in a section of the body instead of getting pushed out, hence the swollen leg.  There's no cure, only treatment.