Ovarian cyst dermoid or serous cystadenoma can be tested with small part for complete pathologic analysis?

Unfortunately Not: The problem with ovarian tumors is that you can have normal cell types adjacent to borderline or malignant cells. The ovary is notorious for hiding cancer cells which is why it's impossible to "eyeball" or sample an ovary and get a complete diagnosis. That's why often the ovary is completely removed if malignancy is suspected. Cancer can also increase in stage if spillage occurs so it's not easy.