The notion of distributional thesaurus, as it was initially defined by Grefenstette (1994), followed by Lin (1998a) and Curran and Moens (2002), is not often considered specifically, probably because of its strong link with the notion of semantic similarity.
the improvement of distributional thesauri has been first a side effect of the improvement of the distributional similarity measures used for their building and more precisely, of the distributional data they rely on.