I have no idea what the itop thing is, but the OCS-NG Inventory can manage duplicates:

Then you can choose the comparison method you'd like:

Then you can expand found couples and choose what to do with them:

Click the MAC to see the duplicates containing it.
But you MUST keep in mind: when you merging duplicates, for example if they appeared due to mysterious reason, the merged computer will NOT have the administrative notes merged:

If dupe-1 have notes added, and newer dupe-2 have no notes, the resulting mergedupe-2 will not have notes also.
PS. UA? Hello from IT techie from RU: f..cings to politics.