Permanent Secretary Mark Sedwill said the titles of the files could not be released yet despite a request from the Home Affairs Select Committee, because they contained personal data that needed to be edited out.
But the mandarin said he had reviewed the list, adding: "Most appear to have contained correspondence from Members of Parliament either asking about government policy or on behalf of constituents."
Mr Sedwill said that kind of correspondence would "normally have been destroyed after two years under the file destruction policy of the time".
In a letter to the committee chairman Keith Vaz today, Mr Sedwill said he had done its bidding by studying the list of titles - but could not yet publish it. He said: "As many of the file titles in the list contain the names of individuals it will have to be redacted before I can provide it to the committee in order both to protect the privacy of the individuals and to avoid the risk of prejudicing ongoing criminal investigations into historic child abuse."
He added that the same applied to the full report of the review - executive summaries of which have already been released.
As a result, they may not be published until a second review of the Home Office's handling of allegations, being carried out by NSPCC head Sir Peter Wanless and Richard Whittam QC is complete in eight to 10 weeks' time.