NOT possible:
Fact 1, ceiling fan blades are not sharp - they're all blunt
Fact 2, velocity of the fan blades generated by the motor, is not
great enough give you more than a gash to your forehead or break
through any bone matter
Fact 3, it would have been in the papers
Actually, it takes a very sharp knife or meat cleaver to lop a
person's head off. Have you seen terrorists beheading a person
alive?? They had to saw at the neck with a rather long sharp knife,
and cut through the spine that connects to the base of the skull.
Believe me, it is MESSY. There'd be copious amounts of blood - not
to mention the wheezing sound from the person's windpipe after the
head comes off.