Hi Konrad, a part of my family on my mother side in Poland, has Spitza as a surname. The problem is, that they have changed their family's name to Śpica. So Josef Spitza b. 1881 in Gostycyno k. Tuchola change it to Śpica. He had married Józefa Kobus, they had daughters Elżbieta Śpitza b.1907, Anna Śpica (Spitza) b.1913, and Feliks Śpica b.1911.
Józefa Kobus second marriage was with Piotr Rauhut, who is my great-grandfather.
Please feel free to email me : kszmi@tlen.pl