You have not bothered to describe the data at all. How many of those columns are numeric ? How many are character?
How do you want to describe "duplicate"? Add a variable to the data? If so, what values should it take?
Or subset the data set?
If the values of variables are all numeric then the RANGE function MIGHT be the easiest approach:
data junk;
set have;
array v(*) <your variables go here>;
if range(of v(*))=0 then <do whatever you want when all the same>;
run;
However, if you have mixes of missing values and actual values that would require adding a check that the nonmissing values equal the number of variables (i.e. the N function).