I just removed Canopy as I wanted to have closer control to what I install on my local Python ecosystem and installed ScipySuperpack instead on OSX Yosemite.
lxml soon came into the game and unfortunately it could not be installed. After some search I found this neat guide here.
The steps are the same ...
brew install libxml2
except the second which should look like:
... and finally
pip install -U lxml
Hope this helped.