The dossier was reviewed by the POTUS, a variety of senators/congressman, and forwarded by a sitting senator to the FBI. In fact, it was reported that a number of government officials had already forwarded this dossier to the FBI and/or CIA.
This isn't some internet rumour that Buzzfeed gave credence to. This was something that was considered significant enough to brief the President on, and long standing senators to alert securities agencies on. 
That certainly seems news worthy to me.