I believe I've found the problem. According to the majority of the forum posts that I've seen, this issue started showing up in Windows 7 SP1 and Server 2008 R2 SP1 systems shortly after Microsoft rolled out IE 10 (Feb 2013). It may not have been IE 10 itself, but rather a later update that is the culprit.
In troubleshooting, I uninstalled several updates around that time frame, but the process continued to eat memory. Once I uninstalled IE 10 the problem went away.
I have since re-installed and uninstalled the update further proving it to be the culprit.
Hopefully this is helpful to someone.
Bill