Exporting Description Information for Fields

I'm trying to export a data dictionery of all fields we have in our Marketo instance along with the description information that we have entered. Is there a way to export field information that includes the description of each field? I know we can use the describe api call to get the list of all fields or we can just download that from the field management, but neither of those includes any of the descriptive information we have added to the field which is important in understanding how that field is used (or if it is obsolete).