The regular expression used internally by Pan to find *bold*, /italic/, and _underlined_ text often matches incorrectly.  For example, portions of the following all match, but shouldn't:

- Look in /usr/local/lib for the file.
- I'm using PHP/Apache/MySQL.

Here's a regex I use for italicization in Vim:

  \s/[^/]\+/[ .!?:;]

This ensures that there is whitespace before the initial slash and whitespace or some kind of punctuation after the second slash.  This might still benefit from some further refinement, but won't be caught by e.g. UNIX-style paths.