Spectrum of ovarian tumors in a referral hospital in Nepal

Correspondence: Dr. Sujan Vaidya, MD Department of Pathology, Kathmandu Medical College, Kathmandu, Nepal E-mail: vaidyasujan@gmail.com Background: Ovarian tumors are common forms of neoplasia in women. Among cancers of the female genital tract, it ranks only below carcinoma of the cervix and the endometrium, but is responsible for approximately 50% of the deaths. They arise from different cell lineages and hence constitute a wide variety of neoplastic entities with diverse morphological and clinical manifestations.

The present study was undertaken so as to find out the frequency of different histological types of ovarian tumors which are prevalent in this part of the country and to seen whether they are significantly different from other populations.

MATERIALS AND METHODS
This is a descriptive study conducted in the department of pathology, Patan Academy of Health Sciences from January 2011 to December 2013.This study included all consecutive cases of ovarian tumors reported in the Department of Pathology over a three year period were included in the study.Tumour-like conditions were excluded from the study.The tumors were classified according to the World Health Organization classification of ovarian tumors. 7tatistical analyses were done by statistical package for social sciences (SPSS) version 17.

Spectrum of ovarian tumors
The age distribution of the patients for all tumors ranged from 10-82 years with a median age of 33 years.Similarly, the median age for benign tumors was 32 years, while for borderline and malignant tumors it was 47 and 40 years, respectively.Approximately, 212(58.40%)tumors were  of benign germ cell tumors was similar to the numbers reported elsewhere.However, the incidence of germ cell malignancies was much higher accounting for 31.58% of all ovarian cancers.
In the western literature, surface epithelial tumors account for 50 to 55% of all ovarian tumors while their malignant counterparts comprise approximately 90% of all ovarian cancers. 17,181,25 However, in our study both these figures were much lower (43.53% and 49.12%, respectively).In the subcontinent, the corresponding figures varied from 61.6 to 90% and 67.44 to 85.71%, respectively. 6,11,13,14rous tumors constitute about 30% of all ovarian tumors, of which approximately 60% are benign, 10% borderline while 30% are malignant. 4,17,18In our study, serous tumors accounted for 25.34% of all ovarian tumors.This figure varied from 32.35% to 50.8% in other studies. 9,10,13In our study, 78.26% of the serous tumors were benign, 3.26% borderline and 18.48% malignant.
Likewise, mucinous tumors account for 12 to 25% of all ovarian tumors, which is similar to our (15.70%)and other studies from the subcontinent. 9,10,13Approximately 75% of these tumors are benign, 10% borderline and 15% are malignant. 4,17,18In our study, 73.69% of these tumors were benign, 17.54 % were borderline and only 8.77% cases were malignant.
In the literature, 5-12% of all ovarian tumors are sex cord stromal tumors 17,18 and 7-12.5% are secondary tumors. 26n our study, sex cord stromal and secondary (metastatic) tumors accounted for only 3.3% and 1.65%, respectively.According to Scully et al, 8 approximately 70% of the secondary (metastatic) tumors are bilateral, where as it was 83.33% in our study.
In agreement with other studies, most ovarian tumors were seen in the reproductive age group, between 20-40 years. 9,11Benign tumors of all were seen in all age groups.Malignant surface epithelial tumors occurred mostly after the 4th decade.][10] In patients under the age of 21 years, approximately 60% of the ovarian tumors are of germ cell origin, and as many as one third of germ cell tumors are malignant, accounting for two thirds of ovarian cancers in the first two decades. 27In our study, 68.18% of the tumors seen in this age group were of germ cell origin and 20% of these germ cell tumors were malignant.

Spectrum of ovarian tumors
seen in the 20-40 year age group.Benign tumors were more common than malignancies in all age groups.Most benign tumors (68.60%) were diagnosed in the 3rd and 4th decades of life, whereas most malignant tumors (50.88%) were seen after the 4th decade, with the exception of malignant germ cell tumors which were mostly seen below the age of 30 (77.78%).Borderline tumors were only seen after the age of 30 (Table 3).
Up to the 1 st four decades, germ cell tumour was the predominant class of tumour and was seen in 149/234 (63.68%) cases.Both benign and malignant germ cell tumors were more prevalent in the 20-29 year age group and were seen in 69/169 (40.83%) and 8/18 (44.44%) cases, respectively.Also, amongst the 5 malignancies seen below the age of 20, 3 (60%) cases were of germ cell origin (Table 3).
From the 4 th decade onwards, surface epithelial tumors were more common and seen in 82/129 (63.57%) cases.Twenty (71.43%) cases of malignant surface epithelial tumors were seen after the 4 th decade, of which 11 (55%) cases were serous carcinomas.Out of the 12 sex cord-stromal tumors, 5 (41.67%) were seen in the 20-29 age group.All 6 secondary (metastatic) tumors occurred after the 2nd decade and were almost evenly distributed amongst the other age groups (Table 3).

DISCUSSION
In this study, 80.72% (n=292) of the ovarian tumors were benign.][10][11][12] The frequency of borderline and malignant tumors in the subcontinent was variable from 0.72 to 4.33% and 9.5 to 30.96%, 9- 16 respectively.In our study, mature cystic teratoma was the most common benign tumour (57%) where as serous carcinoma was the commonest malignancy (29.82%).Similar findings were reported in other studies. 9,10,17,18rm cell tumors constitute 15-30% of all ovarian tumors. 1,17owever, in one North American study, the figure was surprisingly high 58%. 18Similar high incidence of 51.52% was also observed in our study.2][23][24] In our study, the incidence