Rare Ovarian Tumors - An Overview

Introduction:

Tumors are caused due to the rapid and abnormal growth of the cells, accompanied mainly by swelling. These can be seen anywhere in the body. An ovarian tumor is a growth (cancerous or non-cancerous) found in the ovaries ( present in pairs and producing eggs) that are part of the female reproductive system. Rare ovarian tumors can be seen less frequently.

What Is an Ovarian Tumor?

When found in a body, a mass or a cluster of abnormal cells is termed a tumor. It can be a benign (non-cancerous) or a malignant (cancerous) growth. Tumors can affect any body part, such as skin, glands, bones, organs, etc. An ovarian tumor can be benign or malignant, seen in the ovaries, which are present in pairs and are a part of the female reproductive tract. The reason for an ovarian tumor to occur is the formation of abnormal cells due to an acquired faulty gene. Some researchers are working to find out the exact cause of it. The usual symptoms associated with an ovarian tumor are:

• Bloating in the stomach.

• Belly size increases.

• Pain in the stomach or pelvis.

• Constipation.

• Difficulty urinating or urinating frequently.

• The feeling of fullness more quickly than usual when eating

• Cramps during menstruation are often painful.

• Back pain.

• Nausea or vomiting.

• Pain while having sex.

• Vaginal bleeding after menopause.

What Are Rare Ovarian Tumors?

Ovarian cancers are usually uncommon, while some subtypes are sporadic. Of all the ovarian tumors, around 10 to 15 percent of them are considered to be rare. Ovarian tumors are clinically complex tumors. As per the WHO (World Health Organization), ovarian tumors can be classified into three categories: germ-cell, sex-cord stromal, and epithelial. These are described below:

1. Ovarian Germ Cell Tumor: Ovarian germ cell tumors comprise five percent of all ovarian tumors. They are seen mainly in girls and young females, mostly in their 20s and 30s. Earlier in the 1970s, this tumor had a high mortality rate. Still, since the introduction of contemporary BEP chemotherapy (Bleomycin, Etoposide, and Cisplatin, a combination usually for treating testicular cancer), the cure rate is usually 95 percent. Since these tumors often affect a single ovary, fertility-sparing surgery is suggested sometimes.

2. Ovarian Sex Cord-Stromal Tumor: The standard type of ovarian sex cord-stromal tumor is the granulosa-theca tumor, called the ovary's granulosa cell tumor (GCT). These represent two percent of all malignant ovarian tumors. It is usually diagnosed in stage one and confined to a single ovary. Fertility-sparing surgery sometimes becomes possible. Primary and secondary surgeries usually play a vital role in managing the disease, with standard post-surgical treatment, platinum-based chemotherapy. Though almost all of these tumors have a FOXL2 mutation, no drugs target the mutation, so this cannot come into action yet. In patients with recurrence, molecular tumor testing is generally recommended, and treatment considerations include secondary surgery, chemotherapy, bevacizumab, endocrine therapy, and clinical trials whenever available.

3.Epithelial Cell Carcinoma (EOC): Epithelial cell carcinoma accounts for around 95 percent of all ovarian tumors. Some of its subtypes are discussed below:

• Clear Cell Carcinoma: It is a rare type of epithelial ovarian tumor that accounts for five to ten percent of all ovarian cancers and is considered to originate usually from endometriosis within the peritoneal cavity. As with mucinous carcinoma, which is also a sub-type of epithelial cell carcinoma, most patients are seen with early-stage disease, and the prognosis, when detected in early stages, resembles the prognosis for high-grade serous. In contrast, the prognosis for disease detected in advanced stages tends to worsen.

There are several key ways and potential targets for clear cell carcinoma:

• An ARID1A mutation is present in about 50 percent of clear cell carcinomas, which can be effectively targeted by drugs such as Tazemetostat.

• 30 to 40 percent of clear cell carcinomas have a PI3K or AKT or mTOR pathway aberration, which can be targeted by P13K or AKT inhibitors.

• The angiogenesis pathway is active, making Bevacizumab a potential treatment option.

• These tumors frequently express PD-1 or PD-L1, which immune checkpoint inhibitors can target.

• There are various additional potential targets that need further evaluation.

Low-Grade Serous Carcinoma (LSOG): It is another rare type of epithelial ovarian cancer and accounts for around 10 percent of all serous cancers of the ovary. It can originate independently or following the diagnosis of borderline serous tumors. It is primarily seen in young patients. Low-grade serous carcinoma can be chemo-resistant and responsive to endocrine therapy, and patients usually have more prolonged survival compared to high-grade serous ovarian cancer patients. Many patients present with advanced-stage disease, and over 70 percent are seen to recur.

• 20 to 40 percent of low-grade serous carcinomas have a KRAS mutation, which MEK inhibitors may target.

• Five to ten percent have a BRAF mutation, which BRAF inhibitors may target.

• Up to 26 percent have an NRAS mutation.

• Additionally, over 90 percent express the estrogen receptor and might be responsive to hormonal therapies like aromatase inhibitors.

• Bevacizumab might also be effective in targeting the angiogenesis pathway.

• Following primary surgery, patients with low-grade serous carcinoma appear less responsive to chemotherapy than those with high-grade serous carcinoma. It is correct for adjuvant and neoadjuvant chemotherapy and maintenance therapy or therapy for recurrence. This does not mean that LGSOC is entirely unresponsive to chemotherapy. HGSOC is more frequently responsive than it is (high-grade serous carcinoma).

Conclusion:

A tumor is an abnormal growth of the cells and tissues seen in any body part, such as skin, bone, glands, organs, etc. One such tumor is an ovarian tumor that is seen in females. Ovaries constitute a vital organ of the female reproductive tract as it is responsible for the formation of eggs. Any obstruction or abnormal growth in the ovary can lead to fertility issues. Rare ovarian tumors are significantly less frequently found, which include epithelial tumors, germ-cell tumors, and ovarian sex-cord tumors. These rare ovarian tumors can be of benign type as well as malignant type. Advancements in various treatment modalities, such as genomics and molecular biology, assist in their treatment.