[Histopathology and cytology of supposedly benign tumors of the ovary]

Most tumors of the ovary presumed benign according to clinical, biological and imaging data are cysts. A cyst is a newly formed cavity lined by epithelium. It tends to enlarge, and can undergo torsion, rupture and haemorrhage. Most prevalent cystic lesions, i.e. inclusion cysts, serous or mucinous cystadenomas, endometriotic cysts, mature teratoma and other cysts are described. Diagnostic methods of cytology and pathology are described and evaluated: intraoperative examination of cystic and peritoneal fluids are not recommended; intraoperative consultation can be performed on solid parts or implants, if the pathologist is familiar with these lesions, or if primary carcinoma is known. The value of intraoperative examination is good in benign and cancer cases, but unsatisfactory in borderline lesions, especially of mucinous type. Cryopreservation of ovarian tissue can be performed to preserve tumoral and normal tissue in Biobank for research protocol, or to maintain fertility through follicle preservation, in aseptic conditions. Transfer of samples towards the pathology laboratory can be performed either and preferably in fresh state, or in vacuum sealed bags at +4°C allowing a 2-day delay, or after immersion in a 15 × volume of 4% formalin. Cytological samples must be collected on citrate and sent immediately to the pathology laboratory, or fixed volume/volume in of absolute alcohol. The pathologist and the surgeon must collaborate to obtain good practice: intact labelled sample, accompanied by clinical information, transfer according to best local conditions, judicious use of intraoperative examination, knowing its possibilities and limitations, no excess delay of pathology report, even in difficult cases requiring expert opinion.