Pathological classification and grading of primary ovarian carcinoma: experience of the ARTAC ovarian study group

One hundred and fifty-seven cases of high stage ovarian carcinomas (FIGO stage III and IV) have been selected for therapeutic protocol under the aegis of ARTAC. One hundred and forty-six cases have been reviewed, of which 15 were peritoneal tumors: eight ovarian tumors were excluded. One hundred and twenty-three primary ovarian carcinomas have been graded and classified. The slides were reviewed independently by three pathologists with a perfect correlation and no significant difference was observed with the initial diagnosis. The World Health Organisation classification of ovarian epithelial tumors was used as a basis for the study (98 serous types, three mucinous tumors, five endometrioid tumors, two clear cell tumors, five mixed epithelial tumors, seven undifferentiated tumors and three unclassified). The adopted grading associates the degree of architecture differentiation and the cytological features using Broder's classification. The architecture grading or degree of differentiation includes well differentiated, moderately differentiated, poorly differentiated and undifferentiated patterns. The nuclear grading is based on pleomorphism of size and form, hyperchromatism, nucleoli, mitotic figures. The proposed grading based on well-known criterions is simple to use and easily reproducible. Grade 1 (6.5%) are well differentiated tumors with no atypia. Grade 2 (17.89%) are moderately well differentiated tumors without nuclear atypia. Grade 3 (32.52%) correspond to moderately well differentiated tumors with nuclear atypia. Grade 4 (43.09%) are poorly differentiated or undifferentiated tumors with nuclear atypia. The authors consider the different correlations between grade, histological type, stage and prognosis. The implications of these findings are discussed and the results are compared to those of the literature.