[1202] Pathological Diagnosis of Grade in Primary Mucinous Ovarian Tumor

K Wakasa, T Wakasa, M Ohsawa. Osaka City University Graduate School of Medicine, Osaka, Japan; Osaka Red Cross Hospital, Osaka, Japan

Background: Pathological diagnosis of the grade in mucinous tumors is often difficult, because malignant tumors often appear benign, and the judgment of invasion is often complicated. Furthermore, differentiation from the metastatic ovarian tumors is complex.
Design: We studied 196 cases of ovarian mucinous tumor surgically resected in our hospital. Of these 196, benign cases numbered 113, borderline 57, malignant 26. Intraoperative consultation was carried out in 155 of the 196 cases. We verified the accuracy of the pathological diagnoses of frozen sections from these 155 cases by a comparison with the final pathological diagnoses. In 13 borderline and 17 malignant tumors we carried out the immunohistochemical staining of cytokeratin 7 and 20.
Results: In 11 out of the 155 frozen sections of mucinous ovarian tumor, pathological diagnoses of frozen sections were underdiagnoses in comparison with the final pathological diagnoses. Nine out of 48 borderline mucinous tumors were diagnosed as benign, and 2 out of 18 malignant cases were diagnosed as borderline on intraoperative consultation. There was no case of overdiagnosis. The discordance rate was about 7%. In all 11 cases, the reason for the underdiagnoses was the absence of the most atypical area in the frozen sections. Two out of 30 borderline and malignant mucinous tumors were negative for cytokeratin 7. In one of the two cases, autopsy was performed, and no other primary site was demonstrated. In the other case, no other primary site was identified during a two-year follow-up. There was no metastatic tumor in the 57 cases of borderline tumor and 26 cases of malignant tumor. The results of immunohistochemistry for cytokeratin 20 were variable.
Conclusions: The pathological diagnosis of mucinous tumor is difficult because areas showing a variable degree of atypicality are present in the same tumor. Underdiagnosis in intraoperative consultation is inevitable because the number of specimens that can be examined is only one or two. There was no metastatic tumor in the 57 cases of borderline tumor and 26 cases of malignant tumor. Immunohistochemically, most of the ovarian tumors were positive for cytokeratin 7. Cytokeratin 20 was variable in the ovarian mucinous tumors.
Category: Gynecologic & Obstetrics

Wednesday, March 24, 2010 1:00 PM

Poster Session VI # 154, Wednesday Afternoon

 

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