Histopathological Profile and Presentation of Ovarian Tumours: An Observational Study

INTRODUCTION

Among gynaecological cancers, ovarian cancer ranks third, following cervical and uterine cancer.^[1] It has the worst prognosis and highest mortality rate among these cancers.^[2] Due to the common occurrence of ovarian tumours (both benign and malignant) in women of all age groups and the lack of an ideal screening test for early detection, there is often a delay in diagnosis, leading to increased morbidity and mortality.^[3] Most patients present with advanced disease as the symptoms of ovarian cancer are often vague, including persistent abdominal pain, indigestion, abdominal bloating or distention, decreased appetite and weight loss, making diagnosis challenging.^[2,3] In India, ovarian cancer is the third most common cancer in women after breast and cervical cancer, according to the National Cancer Registry Programme.^[4]

Ovarian tumours are classified into different types, including surface epithelial tumours, germ cell tumours, sex cord-stromal tumours, germ cell sex cord-stromal tumours, tumours of rete ovarii and miscellaneous tumours.^[5] Surface epithelial tumours are the most common. Around 90% of ovarian cancers are epithelial ovarian carcinomas, with subtypes including high-grade serous, low-grade serous, endometrioid, clear cell and mucinous carcinomas. Germ cell tumours account for <2% of ovarian cancers and are classified as teratomas, dysgerminomas, endodermal sinus tumours and choriocarcinomas. Stromal cell tumours are the least common, comprising only 1% of all cases.^[6,7] The identification of various histologic patterns of ovarian tumours is crucial for their diagnosis, prognosis and treatment. The degree of differentiation of the tumours can also provide insight into the prognosis. The stage and laterality of the tumour also provide information about its nature.^[6] For example, sex cord-stromal tumours are usually confined to a single ovary, while approximately 65% of metastatic tumours affect both ovaries. This study was conducted to understand the various histopathological variants of ovarian tumours among different age groups, their nature and presentation in women seeking care at a tertiary centre in Southern India.

MATERIALS AND METHODS

This was a retrospective observational study conducted at the Department of Pathology in a tertiary care Institute in South India. Data were collected over a period of 3 years, from 2018 to 2021. The study included all cases of ovarian neoplasms, both primary (benign and malignant) and metastatic, as well as non-neoplastic lesions. The diagnosis of ovarian tumours was based on a histopathological examination performed in the pathology department of the institution. The classification of ovarian neoplasms was based on the World Health Organization classification from 2003. Clinical data were obtained from patient records. The patients were categorised into different age groups to assess the proportion of benign and malignant tumours in each group and to determine the histological types.

RESULTS

Around 131 participants were included in the study. Most of the study participants belonged to the 20–40 years age group (52%) followed by 41–60 years (34%). Around 85% of participants had unilateral ovary lesions, and among the participants with unilateral lesions, the right side was more common than the left side. Table 1 shows the age-wise distribution and clinical profile of the study participants, and Table 2 shows the average size of the ovarian lesions. The age group had no significant difference between participants with various lesion locations. The most common symptoms among all study groups were abdominal pain. About 35% of participants with bilateral lesions had abdominal distension, which was statistically (p = 0.031) higher than unilateral lesions. A round 10 participant had other symptoms such as abnormal menstrual bleeding, pelvic pain, loss of weight and vomiting. One in four participants with bilateral lesions had ascites, and <5% of participants with unilateral lesions had ascites. These differences were statistically significant (p = 0.002). Figure 1 shows the type of ovarian tumours the study participants had. More than half of the lesions were benign (56%), and around 10% were non-neoplastic lesions.

The examination finding of the lesions is shown in Table 3. Most of the lesions were smooth, followed by nodular structure. Most unilateral lesions (Right-81% and left-73%) had a smooth surface and were solid (Right-81% and left-64%) in nature. Among the bilateral lesions, only 30% had smooth surfaces, and 40% were solid. More than half of the unilateral lesions were uniloculated, and many bilateral lesions were multiloculated. These differences in surface, nature and locules were statistically significant. Serous fluid was commonly found in the right-side unilateral lesions, and mucinous fluid was commonly found in the left-side unilateral and bilateral lesions. All participants with torsion had unilateral lesions. Around 40% of participants with bilateral lesions had deposits. More than 60% of unilateral lesions were benign, whereas 60% of bilateral lesions were malignant. The differences in type of neoplasm and presence of deposits were statistically significant. Table 4 depicts the histopathological variants of the ovarian lesions. Commonly seen lesions were serous tumours followed by mucinous tumours.

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Figure 1: Distribution of type of neoplasm among study participants.

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Table 5 shows the comparison of age and clinical profile between the types of neoplastic lesions. Many of the study participants with benign lesions were in the 20–40 years age group (56%), and participants with malignant lesions were in the 41–60 years age group (45%). The most frequent symptoms among participants, with benign (32%) and non-neoplastic lesions (82%), were abdominal pain. About 32% of participants with malignant lesions had abdominal distension, which was statistically (p = 0.031) higher than other lesions. All the participants with ascites had malignant lesions. Around 28% of malignant lesions and 6% of benign lesions were bilateral, and the differences were statistically significant.

The comparison of examination findings of the lesions is shown in Table 6. Most of the benign lesions (89%) had a smooth surface and were solid (90%) in nature. Among the malignant lesions, only 45% had smooth surfaces, and 30% were solid. About two-thirds of the malignant lesions were multiloculated, and the majority of benign and nonneoplastic lesions were uniloculated. These differences in surface, nature and locules were statistically significant. All the participants with deposits were malignant. The most common deposits were found in the peritoneum and omentum [Table 7]. The histopathological pattern of various tumours encountered during our study is shown in the microphotographs, as shown in Figures 2-8.

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Figure 2: (a) Gross Photograph of mature cystic teratoma with pultaceous material and hair. (b) Photomicrograph from mature cystic teratoma showing respiratory epithelium (black arrow), mucous glands (blue arrow) and adipose tissue (yellow arrow). (Haematoxylin and eosin, x1000).

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Figure 3: (a) Gross Photograph of solid, firm ovarian mass with torsion changes. (b) Photomicrograph showing benign spindle cells in whorling (black arrow) and fascicular pattern diagnostic of fibroma of ovary (Haematoxylin and eosin, x1000).

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Figure 4: (a) Magnetic Resonance Imaging of abdomen and pelvis showing ovarian cyst with papillary structures. (b) Gross Photograph showing uniloculated ovarian cyst with large papillary excrescences (black arrow) in wall. (c) Photomicrograph showing papillary projections (black arrow) with complex hierarchial branching pattern. Papillae are lined by pleomorphic columnar cells which showed invasion at focal areas. The features are diagnostic of papillary serous cystadenocarcinoma of ovary (Haematoxylin and eosin, x1000).

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Figure 5: (a) Gross photograph showing ovarian mass with nodular external surface and solid, nodular cut surface. Multiloculated cystic areas filled with mucin seen. (b) Photomicrograph showing multiloculated cyst wall lined by mucin laden columnar epithelium exhibiting tufting, stratification, villous formation (black arrow) and nuclear atypia. Cyst was filled with mucin. There was no invasion. The features are diagnostic of atypically proliferating mucinous tumour of ovary. (Haematoxylin and eosin, x1000).

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Figure 6: (a) Gross photograph showing bilateral ovarian mass with classical nodular surface and maintained shape of ovary. (b) Photomicrograph showing metastatic infiltrating signet ring cells (black arrow) in ovarian stroma.The primary was from gastric signet ring cell carcinoma. The features are diagnostic of Krukenberg tumour of ovary. (Haematoxylin and eosin, x1000).

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Figure 7: Photomicrograph of dysgerminoma showing sheets and lobules of polygonal clear cells with distinct cell membrane (black arrow) and intervening stroma showing lymphocytes (Haematoxylin and Eosin, x1000).

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Figure 8: Photomicrograph of yolk sac component of mixed germ cell tumour showing large pleomorphic tumour cells arranged in glandular pattern (yellow arrow) and extracellular large eosinophilic hyaline globules (black arrow) (Haematoxylin and eosin stain, x1000).

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DISCUSSION

Ovarian cancer is often referred to as a ‘silent killer’ because most patients do not experience significant symptoms until the disease has advanced.^[6] The main objective of our study was to investigate the different types of ovarian tumours in terms of their histopathology, prevalence and presentation in a tertiary care institute. In our study, out of 131 cases of ovarian lesions, 56% were benign tumours, 34% were malignant, 2% were borderline, and 8% were non-neoplastic lesions. These findings were consistent with observations noted in the previous studies, which reported that benign tumours were found to be more common than malignant tumours. ^[7-9]

Ovarian tumours can occur at any age, including infancy and childhood, but the incidence increases with age. In our study, the majority of the study participants with benign lesions were in the 20–40 years age group (56%), while participants with malignant lesions were in the 41–60 years age group (45%). Similar studies have reported comparable findings regarding the age of presentation of ovarian cancers, with most cases of malignant ovarian tumours occurring in the age group above 40 years.^[10]

In terms of tumour characteristics, the study found that more than 60% of unilateral lesions were benign, whereas 60% of bilateral lesions were malignant. Furthermore, both benign and malignant ovarian tumours, which presented as unilateral lesions, were more frequently found in the right ovary compared to the left ovary; however, the difference was not statistically significant. Bilateral involvement is known in ovarian tumours, with the likelihood varying depending on the histologic subtype. Similar results have been reported wherein a predominance of unilateral masses in both benign and malignant ovarian tumours has been observed.^[11]

Surface epithelial tumours account for a significant percentage of ovarian tumours worldwide, with their malignant forms representing many ovarian cancers.^[12] Histopathologically, surface epithelial tumours were the most common type of ovarian tumours in our study, followed by germ cell tumours. The most common type of malignant ovarian tumour in the present study was serous cystadenocarcinoma, followed by mucinous cystadenocarcinoma. This is in line with findings from other studies.^[12,13] Among patients with benign ovarian tumours, serous cystadenoma and mucinous cystadenoma were the most common, followed by mature teratomas. Similar findings were reported in other studies as well, which observed a higher prevalence of serous cystadenoma among benign tumours and serous cystadenocarcinoma among malignant ovarian tumours. ^[14,15]

Germ cell tumours were the second major group of tumours in our study, and their proportion varied in other studies. Mature teratoma (Dermoid cyst) was the most common benign germ cell tumour, while dysgerminoma was the most common malignant germ cell tumour and the findings were consistent with other studies.^[10,16,17]

Screening for adnexal masses can be performed through routine bimanual pelvic examinations in outpatient settings. Pelvic ultrasound detects around 90% of adnexal masses, providing information about the origin, complexity, vascularity and consistency of the tumour.^[6] Tumour markers and adjunctive diagnostic techniques such as magnetic resonance imaging and computed tomography can aid in identifying ovarian masses and detecting metastasis. However, the definitive diagnosis is made through histopathological study.^[6,7]

Overall, this study provides valuable insights into the prevalence, age distribution and histological characteristics of ovarian neoplasms aligning with previous studies and contributing to understanding of the disease.

CONCLUSION

Various clinical factors, including the patient’s age, tumour location, dimensions and histological type, can affect the prognosis of ovarian tumours. Our study found that benign ovarian tumours were more common than malignant tumours across all age groups with malignant tumours being more common at above 40 years. Morphologically, epithelial tumours were the most frequently observed variant, particularly serous and mucinous tumours, followed by germ cell tumours. The most common non-neoplastic lesions were endometriotic cysts. Bilateral involvement was uncommon, with a higher occurrence on the right side.