Itsko is indeed Romanian diminutive (name Itskovici, Ickovici are
derived from), but traces can be also found in Ukrainian - eg.
Ickovicz/Itsykowicz, probably originated in area of Tchernowitz
(Czernowice) between the rivers Dniestr and Prut, where both cultures,
Romanian and Ukrainian have met.
Muntkasch (Munkac) is known as Mukacevo and together with the close by
central town of Ungvar(Uzgorod/Uzhhorod) those locations are presently
under the Ukrainian rule. Area is now called Zakarpatskaya Ukraina
(Transkarpatian Ukraine). Region was originally populated by the Rusins
(Transkarpatian Ukrainians), Slovaks, Hungarians (Magyars) and Jews.
There existed also small Romanian and Gypsies minorites, but Polish
population was rather unknown - you are probably confusing Slovaks with
the Poles, both tribes are Slavs, but a bit different.