In 1979 the large housing estate of Marzahn was separated from Lichtenberg to become an East Berlin borough in its own right and in 1986 the new Hellersdorf district ( including Kaulsdorf and Mahlsdorf ) was split from it . In the course of the population growth Marzahn was separated from Lichtenberg in 1979 to become a borough in its own right and in 1986 the new Hellersdorf district ( including Kaulsdorf and Mahlsdorf ) was split from it .