J Korean Radiol Soc 1999;4 :19 9-8 9 9 4 CT Differentiation of Ovarian Mucinous and Serou s Cys t a d e n o c a rc i n o m a 1 So n g - M ee Cho, M.D., Jae-Young Byun, M.D., Seung-Eun Jung, M.D.2, Bum-Soo Kim, M.D., Jae-Mun Lee, M.D.2, Joon-Mo Lee, M.D.3 Purpose : To assess the differences between imaging findings of mucinous and serous cystadenocarcinomas of the ovar y , as seen on computed tomography (CT). Materials and Methods : The CT findings of 24 patients with mucinous cystadenocar- cinoma (25 tumors) and 26 with serous cystadenocarcinoma (47 tumors) of the ovar y were retrospectively analysed. Images were evaluated for tumor size, contour, CT at- tenuation of locules within the mass, the presence of septal vegetation, the proportion of solid portion within the mass, the presence of calcification, and carcinomatosis peritonei. Results : Mucinous cystadenocarcinomas tend to have a smooth contour (96%), var i - able CT attenuation of locules (80 %), and even size of locules within the mass (88.0 %). Serous cystadenocarcinomas, on the other hand, tend to have an irregular lobulat- ed contour (89.4 %), unevenly sized locules (76.6%), septal vegetation (57.4 %), and a prominent solid portion (59.6%). Bilaterality and carcinomatosis peritonei were more common in serous than in mucinous cystadenocarcinoma. Conclusion : Features which are valuable for the differentiation of mucinous and serous cystadenocarcinomas of the ovar y , as seen on CT, are tumor size, contour, var y - ing locule attenuation and size, septal vegetation, a solid portion, bilaterality and peri- toneal seeding. Index words : Ova r y , neoplasms Ova r y , CT Epithelial cancers are the most common type of ovari- their clinical differentiation is not easy. In order to de- an malignancy, and may be serous (75 %), mucinous (20 termine the basis on which these two diseases may be %) or a mixture of other histologic types (5 %). In terms differentiated, we have therefore evaluated their respec- of their pathology, tumor behavior and prognosis, tive imaging features. serous and mucinous ovarian cancers are different, and Materials and Methods 1Department of Radiology, Kangnam St. Mary’s Hospital, College of Medicine, the Catholic University of Korea During a recent six-year period, CT images were ob- 2Department of Radiology, St. Mary’s Hospital, College of Medicine, the tained from 50 consecutive ovarian cystadenocarcino- Catholic University of Korea 3Department of Gynecology, Kangnam St. Mary’s Hospital, College of ma patients. Pathologic examination revealed 25 muci- Medicine, the Catholic University of Korea nous cystadenocarcinomas (one bilateral) in 24 patients Received June 2, 1999 ; Accepted August 2, 1999 Address reprint requests to : Jae Young Byun. M.D., Departments of aged 45 to 72 (mean, 59) years, and 47 serous cystadeno- Radiology, College of Medicine, The Catholic University of Korea. #505 Banpo-dong, Seocho-gu, Seoul 137-040, Korea. carcinomas (21 bilateral) in 26 patients aged 16 to 71 Tel. 82-2-590-1582 Fax. 82-2-599-6771 E-mail [email protected] (mean, 43) years. In all patients, CT images were ob- ─ 98 9 ─ Song-Mee Cho, et al : CT Differentiation of Ovarian Mucinous and Serous Cystadenocarcinoma tained one week before surgery, and retrospectively e- with a microlobulated contour was found. The propor- valuated. tion of solid portion of the mass was determined by the For CT, a Somatom Plus (Siemens, Erlangen, percentage of solid portion in relation to the entire mass, Germany), with 8-10 mm slice thickness and interval as seen on two dimensional images. The tumor was was used. Six hundred ml diluted diatrizoate meglu- considered mainly cystic when the solid portion com- mine (gastrografin 2%; Schering, Berlin, Germany) was prised 0-20 %, mixed solid and cystic when 20-50 % , orally administered 30-120 minutes before scanning. A and mainly solid when >50 %. Ascites, peritoneal nod- total of 100 ml iopromide 62.3% (Ultravist 300; Schering, ule and omental cake were considered indicative of car- Berlin, Germany) was injected as a bolus at a rate of 2- cinomatosis peritonei. 3 ml/sec using a mechanical injector. Incremental or spi- After comparing the CT imaging findings of mucinous ral scanning began 45 seconds after the start of intra- and serous cystadenocarcinomas, analyses using the venous injection of contrast media from the diaphragm to chi-square test, unpaired Student’s t test, and Mann- the symphysis. Whitney U test were performed. The chi-square test CT images were analyzed independently by two radi- was used to compare the two groups in terms of statisti- ologists without knowledge of the ultrasonographic or cally significant differences in tomor contour and CT at- pathologic results. The imaging features of ovarian ep- tenuation of locules, variation in the size of locules with- ithelial tumors were assessed with regard to tumor size, in the mass, the presence of septal vegetation, the pro- contour, difference in CT attenuation of locules within portion of solid portion within the mass, the presence of the mass, variation in the size of these locules, the pres- calcification, and the frequency of carcinomatosis peri- ence of septal vegetation, the proportion of solid compo- tonei. An unpaired Student’s t test was used to assess nent within the mass, the presence of calcification, bilat- the statistical significance of difference in tumor size be- erality and the frequency of carcinomatosis peritonei. tween the two groups. The Mann-Whitney U test was Tumor size was compared between two groups of ovari- used when one factor such as CA125 level was mea- an carcinomas by measuring the greatest diameter of sured on at least an ordinal scale. A p value of less than the masses. Tumor contour was defined as either s- 0.05 was considered staticstically significant. mooth or lobulated. Variations in the size of locules within the mass was subjectively defined as even or un- Re s u l t s even. Septal vegetation was considered to be present when lobulated endocystic or exocystic septal growth The clinical symptoms of patients with serous and A B Fig. 1. 71-year-old woman with left mucinous cystadenocarcinoma. A . Contrast enhanced pelvic CT shows a huge multiocular cystic mass with smooth contour, honeycombing appearance, and dif- ferent attenuation of locules. B. Lower level CT scan shows calcification (arrow) in the thickened septum (arrowheads). ─ 99 0 ─ J Korean Radiol Soc 1999;4 :19 9-8 9 9 4 mucinous cystadenocarcinomas were abdominal mass, noma patients (Fig. 4 ; p = .0001). Two cases of muci- bloating or mild abdominal pain. The differential imag- nous cystadenocarcinoma showed pseudomyxoma peri- ing features of serous and mucinous cystadenocarcino- to n e i . mas are summarized in Table 1. - The diameter of mucinous tumors was 8 27 (average, Di s c u s s i o n 15) cm and that of serous tumors was 3-18 (average, 8) cm (p<.001). Contour was smooth in 24 of 25 mucinous Common epithelial tumors of the ovary include cystadenocarcinomas (96 %) and lobulated in 42 of 47 serous, mucinous, endometrioid, clear cell, and other- serous cystadenocarcinomas (89.4 % ; p = .0001). CT at- tenuation of the locules varied in 20 of 25 mucinous tu- Table 1. CT Features of Mucinous and Serous Cystadenocarci- noma of the Ovary mors (Fig. 1), but in all but one serous cystadenocarcino- Cy s t a d e n o c a r c i n o m a ma (p=.0001). The size of locules within the mass was Fi n d i n g s even in 22 of 25 mucinous cystadenocarcinomas (88 % ; Mucinous (n=25) Serous (n=47) Fig 1), and uneven in 36 of 47 serous cystadenocarcino- Si z e 8-27 (mean,15) cm* 3-18 (mean, 8) cm* Lobulated contour 01 (4.0%) 42 (89.4%)* mas (76.6 % ; p = .0001). Septal vegetation was seen in Difference in cham. atten. 20 (80.0%)* 01 (2.2%) 27 serous cystadenocarcinomas (Fig. 2), but in only two Honeycombing appearance 22 (88.0%) 11 (23.4 %)* mucinous cystadenocarcinomas (p = .0001). Vegetation of septa 02 (8.0%) 27 (57.4%)* The proportion of intratumoral solid portion is sum- Ca l c i f i c a t i o n 05 (20.0%) 12 (25.5%) Bi l a t e r a l i t y 01 patient 21 patients* marized in Table 2. This was larger in cystadenocarcino- Carcinomatosis peritonei 00 patient 12 patients* mas (Fig. 2, 3) than in mucinous cystadenocarcinomas * p < 0.001 (p = .003). Calcifications within the tumor were seen in cham. : locule; atten. : CT attenuation 5 of 25 mucinous cystadenocarcinomas (20%) and 12 of 47 serous cystadenocarcinomas (25.5 %), with no statis- Table 2. Proportion of Solid Portion within the Mass in Mucin- tically significant difference between the two groups (p ous and Serous Cystadenocarcinoma = 0.773). Solid portion Mu c i n o u s Se r o u s Bilateral tumors were more common in the serous 00 - 20 % 20 (80.0%) 09 (19.1%) cystadenocarcinoma group than in the mucinous cys- 20 - 50 % 04 (16.0%) 10 (21.3%) tadenocarcinoma group (p = .0001). Carcinomatosis > 50 % 1 (4.0%) 028 (59.6%)* peritonei were found in only 12 serous cystadenocarci- * p<0.05 Fig. 2. 42-year-old woman with bilateral, mainly cystic masses Fig. 3. 72-year-old woman with bilateral serous cystadenocar- with large solid portions and vegetations (arrow) on postcon- cinoma. Contrast enhanced pelvic CT scan shows bilateral o- trast pelvic CT. Ehnancement of solid portion and intense en- varian masses, mainly solid on the left and solid and cystic on hancement of cystic and tumor wall can be visualized.