TMTOWTDI:

$ perl -nE '
    chomp;
    my @x = split /\|/;
    my ($y) = grep $x[$_] =~ /,/, 0..$#x;
    for (split /,/, $x[$y]) {
        splice @x, $y, 1, $_;
        say join "|", @x;
    }
'
a,b,c|d|e
a|d|e
b|d|e
c|d|e
a|b,c,d|e
a|b|e
a|c|e
a|d|e
a|b|c,d,e
a|b|c
a|b|d
a|b|e
[download]

Although, for dealing with spreadsheet data, Text::CSV would always be my first port of call.

    my @z = split /,/, $x[$y];
    for (@z) {
[download]

    for (split /,/, $x[$y]) {
[download]