What are the other Names for this Condition? (Also known as/Synonyms)

• Ovarian Malignant Mesothelioma (OMM)
• POMM (Primary Ovarian Malignant Mesothelioma)
• Primary Ovarian Malignant Mesothelioma (POMM)

What is Malignant Mesothelioma of Ovary? (Definition/Background Information)

• Malignant Mesothelioma of Ovary is an extremely uncommon, malignant tumor of the ovary. It is a primary ovarian tumor, indicating that the tumor arises from the ovary
• A malignant mesothelioma is a malignancy of the mesothelial cells (membrane lining the various body cavities). Based on location of the tumor, 5 body sites have been identified which include:
  • Pleura (lung)
  • Peritoneum (abdomen)
  • Pericardium (heart)
  • Outer lining of the testis, called tunica vaginalis
  • Ovary
• Malignant Mesothelioma of Ovary may be associated with asbestos exposure, endometriosis, and long-term smoking. The cause of formation of the tumor is not well understood, but many genetic mutations have been reported
• Large-sized tumors may cause abdominal and pelvic pain, discomfort, and weight loss. The complications of Ovarian Malignant Mesothelioma (OMM) include infertility, metastasis to various regions, and recurrence following its surgical removal
• The treatment of Malignant Mesothelioma of Ovary is undertaken through surgery. However, since it is difficult to remove the entire tumor, chemotherapy and immunotherapy may be proposed
• The prognosis of Malignant Mesothelioma of Ovary is generally poor due to local invasion and metastasis of the malignancy to various body sites

Who gets Malignant Mesothelioma of Ovary? (Age and Sex Distribution)

• Malignant Mesothelioma of Ovary is an extremely rare tumor type
• The tumor is seen in a wide age group of women; between ages 16-63 years and average age 52 years
• No racial or ethnic group preference is generally noted

What are the Risk Factors for Malignant Mesothelioma of Ovary? (Predisposing Factors)

Currently, no definitive risk factors are noted for the development of Malignant Mesothelioma of Ovary. But it may be associated with the following factors:

• Association with asbestos/fiberglass exposure; the tumors may often develop many years after exposure to these substances. Workers exposed to asbestos include the following and those involved in occupations such as:
  • Manufacturing of industrial products containing asbestos such as paints, insulation, floor tiles, ceiling, etc.
  • Construction workers, home builders
  • Electricians
  • Firefighters
  • Demolition workers
  • Military personnel
  • Those working in chemical plant manufacturing facilities, refineries, power plants, etc.
  • Shipyard workers
• Secondary asbestos exposure (inhalation) during the job, when one may be exposed being in the vicinity. The environmental asbestos exposure can occur in a variety of ways
• Chronic smoking
• Endometriosis: The presence of benign endometrial tissue in abnormal locations outside of the uterus in the pelvis and occasionally, the abdomen
• In rare cases, treatment for abdominal cancers using radiation therapy may cause the formation of malignant mesothelioma
• Exposure to eronite, a type of naturally-occurring mineral fiber, in some parts of the world (e.g. Turkey)
• Family history of mesothelioma: Mutations in BAP1 gene that can run in some families can increase the risk for malignant mesothelioma. The gene mutation can also cause an increased risk for a variety of cancers, such as ocular melanoma, clear cell renal cell carcinoma, liver cancer including intrahepatic cholangiocarcinoma, melanoma of skin, etc. in such individuals
• In experimental animal models, simian virus 40 (SV40, which is generally found in monkeys and humans) has been shown to cause malignant mesothelioma. However, whether SV40 causes mesothelioma in humans is not yet definitely established

Note:

• The adverse health effect caused by smoking and exposure to asbestos may act as a combination factor in some individuals and result in a much amplified risk for mesothelioma
• In some cases, no association to any of the above factors may be identified

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Malignant Mesothelioma of Ovary? (Etiology)

The exact cause and mechanism of formation of Malignant Mesothelioma of Ovary is unknown. However, the tumor formation may be influenced by exposure to certain carcinogenic substances (such as asbestos fibers), endometriosis, and radiation therapy for cancer.

• Mesotheliomas have been shown to have a variety of different genetic mutations
• Long-term exposure to asbestos: Due to its relative rarity, it is not definitely established if asbestos exposure results in Ovarian Malignant Mesothelioma
• In general, it is known that cancers form when normal, healthy cells begin transforming into abnormal cells - these cancer cells grow and divide uncontrollably (and lose their ability to die), resulting in the formation of a mass or a tumor
• The transformation of normally healthy cells into cancerous cells may be the result of genetic mutations. Mutations allow the cancer cells to grow and multiply uncontrollably to form new cancer cells
• These tumors can invade nearby tissues and adjoining body organs, and even metastasize and spread to other regions of the body

What are the Signs and Symptoms of Malignant Mesothelioma of Ovary?

The signs and symptoms of Malignant Mesothelioma of Ovary may include:

• The presence of a solid ovarian mass; the mass may be bilateral, but of different sizes
• The tumors involve the surface of the ovary
• Abdominal pain and swelling; abdominal discomfort and heaviness
• Pain in the pelvic region; lower back pain
• Low-grade fever and profuse sweating
• Tiredness or fatigue, shortness of breath
• Fainting or feeling faint, dizziness
• Swelling in the lower legs
• Weight loss
• Frequent urination due to compression/pressure of large-sized tumors

There are no signs and symptoms during the initial stages of tumor growth and development. Also, small-sized tumors usually do not cause any symptoms. But, occasionally they may become painful, if the surrounding structures are compressed.

How is Malignant Mesothelioma of Ovary Diagnosed?

The following tools may be used towards establishing a diagnosis of Malignant Mesothelioma of Ovary:

• Complete evaluation of family (medical) history, along with a thorough physical examination
• Ultrasound scan of the pelvis: It is a noninvasive procedure that uses high frequency sound waves to produce real-time images
• Transvaginal ultrasound: An ultrasound is inserted into the vagina and the mass is examined using sound waves
• Abdominal and pelvic CT scan: It is a noninvasive procedure that provides more details of soft tissues, blood vessels, and internal organs
• Pelvic MRI scan: It is a noninvasive medical test that uses a powerful magnetic field to produce images of soft tissues, bones, organs, and all other internal structures of the abdomen and pelvis
• Hysteroscopy: This procedure involves placing a probe through the cervix to examine the cavity of the uterus
• Hysterosalpingography: It is usually performed in individuals with infertility. In this procedure, the structure of the uterus and fallopian tubes are studied by using a dye and X-ray images
• Whole-body PET scan, bone scan of affected region to check for tumor metastasis. This helps with the staging of the tumor
• Tissue biopsy of the tumor:
  • A biopsy of the tumor is performed and sent to a laboratory for a pathological examination. A pathologist examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis. Examination of the biopsy under a microscope by a pathologist is considered to be gold standard in arriving at a conclusive diagnosis
  • Biopsy specimens are studied initially using Hematoxylin and Eosin staining. The pathologist then decides on additional studies depending on the clinical situation
  • Sometimes, the pathologist may perform additional studies, which may include immunohistochemical stains, electron microscopy, and molecular studies to assist in the diagnosis

Note:

• Almost all ovarian mesotheliomas belong to the epithelial type with papillary, tubulopapillary, glandular, or solid subtypes
• Due to the rarity of these tumors, the diagnosis of this malignancy can be missed. It can even cause diagnostic challenges during a frozen section biopsy

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Malignant Mesothelioma of Ovary?

Complications due to Malignant Mesothelioma of Ovary could include:

• Infertility
• Metastasis of the tumor to other sites in the body such as to the lymph nodes
• Recurrence of the tumor after surgery, when the entire tumor is not removed
• Blood loss during invasive treatment methods may be heavy
• Damage of vital nerves, blood vessels, and surrounding structures during surgery
• Side effects from chemotherapy (toxicity), radiation therapy (radiation fibrosis)

How is Malignant Mesothelioma of Ovary Treated?

In general, Ovarian Malignant Mesothelioma is a highly-aggressive cancer and the treatment can be challenging. A multidisciplinary approach with a team of healthcare specialists and experts from various medical fields may be necessary to treat the cancer at a healthcare institution that has the experience and expertise in dealing with such high-grade cancers.

The treatment measures for Malignant Mesothelioma of Ovary may include a combination of the following:

• Surgery: Complete excision where possible is attempted. Even though it may not be curative, it can aid in the diagnosis and help relieve symptoms. The healthcare provider may undertake the following surgical procedures:
  • Oophorectomy: The surgical removal of one or both ovaries
  • Salpingo-oophorectomy: It is a surgical procedure that is characterized by the surgical removal of the fallopian tube and ovary
• Radiation therapy and/or chemotherapy: Radiation therapy is usually avoided, since the ovary is close to many vital organs
• Immunotherapy: It is a newer method of treatment that has shown promising results in some individuals. The healthcare provider will determine if immunotherapy is to be employed in treating the tumor
• Embolization (clotting the vessels in the tumor) may be used to provide temporary relief from the symptoms and reduce blood loss during a surgical procedure
• Follow-up care with regular screening and check-ups are important

How can Malignant Mesothelioma of Ovary be Prevented?

Current medical research has not established a way of preventing the formation of Malignant Mesothelioma of Ovary. However, the following factors may be considered to reduce the risk of cancer development:

• Avoid or stop smoking: Individuals, who are smokers or have a prior history of the condition or suffer from other lung diseases, should regularly follow-up with their primary care physician to ensure that their lung functions are normal
• Reducing exposure to known causative agents such as asbestos and asbestos products 
• Early detection of exposure to asbestos dust particles can help avoid further exposure
• Wearing appropriate respirators and masks while performing jobs that involve dust, chemicals, and metals
• While working in industry, maintain a clean work area that is dust-free. Also, regularly shower and change clothes after industrial work
• Ensure that industrial safety regulations for exposure to hazardous materials is adhered to at workplaces
• Ensure that the industries strictly comply with implementation of prevalent statutory codes on occupational safety measures, especially with respect to workplace exposure
• Undertake routine screening of individuals working in environment where exposure to asbestos is evident
• Government regulations have decreased or even eliminated the use of asbestos through increased safety measures and through the usage of substitute products (instead of asbestos)
• It is recommended that regular screening be undertaken for mesothelioma, if any of the following tumors are observed:
  • Clear cell renal cell carcinoma
  • Intrahepatic cholangiocarcinoma (a type of liver cancer)
  • Cutaneous melanoma
  • Uveal or ocular melanoma

Due to its high metastasizing potential and recurrence rate, regular medical screening at periodic intervals with blood tests, scans, and physical examinations, are mandatory for those who have already been treated for this tumor.

What is the Prognosis of Malignant Mesothelioma of Ovary? (Outcomes/Resolutions)

• The prognosis of Malignant Mesothelioma of Ovary is generally poor. Death mostly occurs due to spread of cancer, large size of tumor, or severely affected function of adjoining organs
• Study reports indicate that the mean survival period following diagnosis of the tumor is about the same as peritoneal mesothelioma, which is less than 12 months
• Nevertheless, the prognosis depends on a combination of factors, such as:
  • Age of the individual: Older individuals generally have poorer prognosis than younger individuals
  • Grade of the tumor: It is considered as a helpful parameter in predicting the prognosis
  • Response to treatment and medical therapy: Tumors that respond to treatment have better prognosis compared to tumors that do not respond to treatment
  • The size of the tumor and the extent of its invasion: Individuals with small-sized tumors fare better than those with large-sized tumors
  • Stage of cancer per FIGO (or TNM): With lower-stage tumors, when the tumor is confined to site of origin, the prognosis is usually excellent with appropriate therapy. In higher-stage tumors, such as tumors with metastasis, the prognosis is poor
  • Cell growth rate of the cancer (its ki-67 value): The ki-67 value is based on a protein found in cells that is a good indicator of how fast the tumor cells are growing. The ki-67 value is determined by a pathologist and is usually mentioned in the pathology report
  • Overall health of the individual: Individuals with overall excellent health have better prognosis compared with those with poor health
  • Individuals with bulky disease have a poorer prognosis
  • Involvement of the regional lymph nodes, which can adversely affect the prognosis
  • Involvement of vital organs may complicate the condition
  • The surgical respectability of the tumor (meaning, if the tumor can be removed completely)
  • Whether the tumor is occurring for the first time, or is a recurrent tumor. Recurring tumors have worse prognosis compared to tumors that do not recur
  • Progression of the condition makes the outcome worse

Additional and Relevant Useful Information for Malignant Mesothelioma of Ovary:

Asbestos exposure may not always cause a malignant process in the body. But, in addition to malignancy, it can also cause the following conditions:

• Benign pericardial effusion
• Benign peritoneal effusion
• Benign pleural effusion
• Diffuse pericardial thickening
• Diffuse peritoneal thickening
• Diffuse pleural thickening
• Idiopathic pulmonary fibrosis
• Pericardial calcification
• Pericardial plaque
• Peritoneal plaque
• Pleural plaque