Found 15cm mass covering both ivaries

Hi I have just found out I have a 15cm mass with solid parts covering both ovaries . I also have asiites in abdomen. I have a ca125 of 79 but all other tumour markers are negative. I have had a ct scan and there is nothing anywhere else it is confined to the pelvis . I realise I will need surgery but could this be a dermoid cyst and still have ascites ? I’m driving myself mad looking everything up all the time .thanks