De or het tumormassa?

The correct Dutch article is:

de tumormassa

How to use tumormassa

the tumormassade tumormassa
this tumormassadeze tumormassa
that tumormassadie tumormassa
our tumormassaonze tumormassa
your tumormassajouw tumormassa
every tumormassaelke tumormassa
which tumormassa?welke tumormassa?
a big tumormassa / the big tumormassaeen grote tumormassa, de grote tumormassa