The Dutch youngster had an unconvincing first season in Italy and is considering a return home, but the Eredivisie side have not reached an agreement with the Nerazzurri
The 19-year-old is Twente's top candidate to bolster their attacking options in the summer after the Eredivisie side sold Luuk de Jong to Borussia Monchengladbach earlier in the month.
Dutch sources now claim that negotiations have reached an impasse after a meeting between Twente president Joop Munsterman and Inter officials in Italy on Tuesday as the two clubs are still some distance apart in Castaignos' valuation.
"We will now discuss this matter internally," Munsterman told reporters.
Castaignos endured a disappointing first season at Inter following his transfer from Feyenoord last summer, making six Serie A appearances for the Nerazzurri.