Neglect

You may say the radiologist does not intend to have such a meaning. To go one step forward, we clinicians who read the report know that he is just being protective and should not react excessively.

However, no layman would take that statement lightly. For that reason, practising physicians would be forced to go ahead with further (futile) investigation to exclude that remote possibility. We know that if we do nothing, patients and their family would have enough ground to accuse our negligence - because the possibility of tumor is mentioned in the original report. Ironically, if the possibility of tumor is not mentioned in the report, neither the radiologist nor the clinician could easily (not impossible, of course) be challenged even if the patient really turns out to have a tumor.

You see? The scenario is not a medical problem, but an economic one, or an illustrative case of the game theory: A trivial gain of one side is transferred to an excessive cost of the other. Unlike the classical paradox, the relationship between the two sides is one-way, and the receiving side could not have any gain (or minimize the risk) by shifting the burden back - although we can pass it on and let the patient or the health care system to shoulder the cost.