According to modern scientific literature, among all ovarian tumors, the borderline type occurs from 5 to 15%. This study analyzed the clinical and morphological features and histological variants of borderline types of ovarian tumors. The results of the study showed that among the borderline type of ovarian tumors, serous (46.8%) and mucinous types (42.7%) are more common, while other types, such as endometrioid, mesonephroid, Brenner, and mixed variants make up a low percentage. It was found that serous cystic tumors, in most cases bilateral, common cyst, cystadenoma, papillary adenoma histologically consists of two epithelia, that is, from the mesothelium and secretory cells, it is confirmed that with malignancy, elongated and basaloid cells are metaplastic. It was observed that mucinous borderline tumors were mainly found on one side, disabled adenofibroma, cystoadenomas were filled with mucous contents, monolayer epithelium was metoplasized with stratified epithelium. Among the rare borderline tumors, the endometrioid type, Brenner, mesonephriodal and mixed type were identified.
