Cystic Mesothelioma

What Is Cystic Mesothelioma?

Cystic mesothelioma is a condition that causes benign, or noncancerous, tumors to grow in the lining of the abdomen. Also known as benign multicystic peritoneal mesothelioma, recurrence of these tumors is common. Because of BMPM’s potential for recurrence, experts debate if it should be classified as a “borderline tumor.” But it isn’t considered a malignant, or cancerous, subtype of mesothelioma.

 Key Facts About Cystic Mesothelioma

• Cystic mesothelioma is a benign tumor that mostly forms in the lining of the belly called the peritoneum.
• BMPM most often affects women under 50, unlike malignant mesothelioma, which is more common in men.
• Diagnosis often happens during surgery for other conditions since BMPM’s most common symptoms – abdominal pain, bloating and fluid buildup – are common to many conditions.
• Surgery to remove tumors is the primary treatment. BMPM tumors commonly recur and require long-term monitoring.

Women under 50 are more likely to develop cystic mesothelioma than other groups more likely to develop malignant mesothelioma. This condition is very rare, with only 200 cases recorded globally as of late 2024.

A December 2024 case study described a 26-year-old woman who had abdominal pain. CT scans showed a lesion near her colon. The lesion was surgically removed and biopsied. Doctors diagnosed it as multicystic peritoneal mesothelioma.

Symptoms of Cystic Mesothelioma

Symptoms of cystic mesothelioma include abdominal pain, bloating and fluid buildup (ascites). The condition can mimic other abdominal issues, making early detection challenging. Many cases are only found during surgery for unrelated conditions. 

Common Symptoms 

• Abdominal pain
• Bloating
• Fluid buildup (ascites)

A 2025 research study shows people have different experiences with symptoms. Some patients also report experiencing fatigue, nausea and unexplained weight changes. Some people experience severe discomfort. Others may have no noticeable mesothelioma symptoms. Because symptoms vary from patient to patient, it’s essential that at-risk people have routine medical check-ups.

Is Cystic Mesothelioma Cancerous?

Most cases of cystic mesothelioma are noncancerous. A cancerous condition is rare. But because it’s possible, continued monitoring is often necessary. Some medical professionals argue BMPM shares characteristics with tumors that aren’t considered fully cancerous but have the potential to become cancerous if left untreated.

Other Names for Cystic Mesothelioma

• Benign multicystic peritoneal mesothelioma 
• Multicystic mesothelioma
• Peritoneal cystic mesothelioma

The recurrence rate for cystic mesothelioma can be as high as 50%, according to a 2024 ScienceDirect study. Standard treatment is surgical removal, with follow-up care to monitor for recurrence.

What Causes Cystic Mesothelioma?

The exact cause of cystic mesothelioma is unknown. There is no proven genetic link. While the cause is unclear, hormonal factors and chronic inflammation may be risk factors. One study from the International Journal of Gynecological Pathology concludes that changes from endometriosis are a direct cause of BMPM. 

Possible Risk Factors

• Chronic inflammation
• Hormonal factors
• More common in women under 50
• Possible association with endometriosis

Unlike other mesothelioma types, asbestos exposure isn’t a confirmed cause. BMPM’s risk factors suggest cystic mesothelioma may develop under unique biological conditions, differing from asbestos-related peritoneal mesothelioma.

How Is Cystic Mesothelioma Diagnosed?

Doctors diagnose cystic mesothelioma using imaging tests and biopsies. Imaging techniques, such as CT scans and MRIs, are commonly used to locate cystic growths before confirming the diagnosis with a biopsy.

A biopsy is a minor surgical procedure that uses a thin tube fitted with a light and camera. Doctors identify abnormal growths and collect tissue samples through a small abdominal incision. The samples are sent to the lab, where a pathologist confirms the BMPM diagnosis.

Similar to the challenges with a mesothelioma diagnosis, misdiagnosis is common. These diagnostic tools help doctors distinguish cystic mesothelioma from other peritoneal disorders. 

Malignant mesothelioma usually forms calcified plaques or nodules, while cystic mesothelioma forms liquid-filled cysts. Malignant mesothelioma cells also display increased activity, which doctors detect with special lab tests using stains (immunohistochemical staining).

Cystic Mesothelioma Treatment Options

Surgery is the primary treatment for cystic mesothelioma. In some cases, doctors use heated intraperitoneal chemotherapy, or HIPEC, to reduce recurrence risks. Early intervention often improves outcomes and limits complications.

Because BMPM slowly grows and doesn’t spread, its prognosis is much better than malignant mesothelioma. About 50% of all patients will experience a recurrence. After diagnosis, patients must have routine follow-up imaging.

Treatments for Cystic Mesothelioma

1. Surgical removal: Eliminates cystic tumors but may not prevent recurrence.
2. HIPEC therapy: Heated chemo is applied directly to the abdomen during surgery.
3. Ongoing monitoring: Regular imaging tests are done to detect recurrence.

A 2024 case study described a 43-year-old woman who had a constant dull ache throughout her lower abdomen. After an ultrasound revealed an abnormal mass, a biopsy confirmed her diagnosis. She was treated with tumor-removing surgery and then HIPEC.

She recovered well without complications. At her 1-year follow-up, she had no symptoms. A CT scan showed the mass was gone, and there were no signs of swollen lymph nodes.

Common Questions About Cystic Mesothelioma

Can benign cystic mesothelioma turn malignant?

An incidence of benign cystic mesothelioma turning cancerous is extremely rare, but recurrence is common. Few cases of cystic mesothelioma have shown characteristics of malignancy, which is why long-term monitoring is essential. Regular check-ups, imaging scans and consultations with a mesothelioma specialist can help detect any changes early.

What is the difference between multicystic mesothelioma and other types?

Multicystic mesothelioma is noncancerous. Malignant mesothelioma is aggressive and linked to asbestos. Multicystic mesothelioma tends to grow more slowly and doesn’t spread in the same invasive manner. Their treatments and prognosis also differ significantly, with benign forms having a better long-term outlook.

Is cystic mesothelioma hereditary?

No genetic link has been established. However, some familial patterns have been observed in rare cases. Research is ongoing.

What are the chances of cystic mesothelioma coming back after treatment?

Recurrence rates are high. Many people have multiple surgeries over time, as cystic mesothelioma can regrow. While HIPEC therapy may help reduce recurrence risks, consistent monitoring and follow-up appointments are critical for managing the disease effectively.

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