Case is only applicable to Dutch in some archaic forms still surviving in the language in idiomatic expressions (Articles, Relative, Personal and Interrogative Pronouns). It is only present in the CELEX Wordforms Lexicon. The tags are the same as for Nouns:
Ge: Genitive singular: `des', `dezer', `harer', ...
Gm: Genitive plural: `aller', `hunner', `onzer', ....
De: Dative singular: `aller', `den', `der', `dien', ....
Dm: Dative plural: `haren', `hunnen', `mijnen', `onzen', `uwen', `zijnen', ....