Item turned out to be a small thing (4)
I believe the answer is:
mite
'a small thing' is the definition.
(I've seen this in another clue)
'item turned out' is the wordplay.
'turned out' is an anagram indicator (turn out can mean to organise).
'item' is an anagram of 'MITE'.
'to be' is the link.
(Other definitions for mite that I've seen before include "Minute creature" , "Minute arachnid" , "The widow's contribution, just in time" , "The widow's small donation" , "The widow's small offering" .)