also to "sign-out" a case is a big deal. there can be informal discussion with a doctor about his patient and what the patient's diagnosis is, but once a case is "signed-out", a written/electronic report is part of the patient's official medical record with the pathologist's signature.
In most instances a surgeon or oncologist can be darn sure a patient has a certain disease but they usually won't treat it until a pathologist has put out a signed-out tissue diagnosis.