Frequently Asked Questions About Testicular Mesothelioma

What is testicular mesothelioma?

Testicular mesothelioma—more precisely known as mesothelioma of the tunica vaginalis testis—is an extremely rare form of cancer that develops in the tunica vaginalis, a thin membrane that surrounds the testicle. Fewer than 300 cases have been reported in medical literature worldwide, accounting for less than 1% of all mesothelioma diagnoses.

The tunica vaginalis is part of the protective sac that encloses each testicle. It is made up of mesothelial cells, the same type of cells found in the linings of the lungs (pleura), abdomen (peritoneum), and heart (pericardium). These linings are collectively known as mesothelium, and cancers that originate there are called mesotheliomas.

Shared Embryological Origins: Testicles and Ovaries

The reason men can develop mesothelioma of the testicle and women can develop mesothelioma of the ovary comes down to shared embryological origins. During fetal development, both the testes and ovaries begin from the same basic tissue structures near the kidneys. In males, the testes descend into the scrotum, dragging a piece of the peritoneal lining (from the abdominal cavity) with them. This becomes the tunica vaginalis—essentially a pocket of peritoneum wrapped around the testicle.

In females, the ovaries remain in the abdominal cavity and are surrounded by the peritoneal mesothelium and a thin mesothelial coating. Because of these anatomical connections, asbestos fibers inhaled or ingested can migrate through the body and become lodged in either the tunica vaginalis in men or the peritoneum and ovarian surface epithelium in women.

Asbestos Exposure and Reproductive Cancers

This anatomical similarity helps explain why asbestos exposure—primarily through inhalation or secondary contact (such as washing contaminated clothing)—can cause:

• Testicular mesothelioma in men

• Peritoneal mesothelioma or ovarian cancer in women

In fact, in 2011, the International Agency for Research on Cancer (IARC) officially classified asbestos as a known cause of ovarian cancer, based on multiple epidemiological studies and autopsy findings of asbestos fibers in ovarian tissues.

What causes testicular mesothelioma?

The primary cause of testicular mesothelioma (mesothelioma of the tunica vaginalis) is asbestos exposure. While this link was long suspected based on individual case reports and biological plausibility, solid epidemiological proof was lacking—until recently.

In 2020, researchers published the first analytical case–control study establishing a statistically significant association between occupational asbestos exposure and testicular mesothelioma. The study used data from the Italian National Mesothelioma Registry (ReNaM), one of the world’s most comprehensive surveillance systems for mesothelioma.

1. Marinaccio A, et al. Association between asbestos exposure and pericardial and tunica vaginalis testis malignant mesothelioma: a case–control study. Scand J Work Environ Health. 2020;46(6):609–617. https://doi.org/10.5271/sjweh.3895

What the Study Found

From 1993 to 2015, researchers identified 80 cases of tunica vaginalis testis mesothelioma. When these were compared with control subjects:

• Men with occupational asbestos exposure were 3.42 times more likely to develop testicular mesothelioma than unexposed individuals (OR 3.42, 95% CI 1.93–6.04).

• Even “possible” occupational exposure carried significantly elevated risk (OR 2.57, 95% CI 1.25–5.31).

• Non-occupational exposure (e.g., environmental or household contact) was too rare to analyze meaningfully.

This definitively confirms what doctors and researchers have long believed: asbestos is the cause of nearly all cases of testicular mesothelioma.

What are the common symptoms of testicular mesothelioma?

The most common early signs of testicular mesothelioma—also called mesothelioma of the tunica vaginalis—can be subtle and are frequently mistaken for benign conditions. That’s why many patients experience delays in diagnosis until surgery or biopsy reveals the true cause.

The Most Frequently Reported Symptoms

According to a comprehensive literature review and case study analysis by Bisceglia et al. (2010), the most commonly reported symptoms are:

(Bisceglia, M., Dor, D., Carosi, I., et al. (2010). Paratesticular mesothelioma. Report of a case with comprehensive review of literature. Advances in Anatomic Pathology, 17(1), 53-70. https://doi.org/10.1097/PAP.0b013e3181c66fbc)

When hydrocele is the presenting symptom, it is often attributed to a benign cause such as trauma, infection, or aging. However, in testicular mesothelioma, the hydrocele may be caused by tumor irritation of the tunica vaginalis, leading to persistent or recurrent fluid buildup that doesn’t respond to standard treatments like aspiration or hydrocelectomy. Tumors may also present as a palpable lump or swelling, which may be mistakenly diagnosed as a hernia, epididymitis, or spermatocele.

How is testicular mesothelioma diagnosed?

Diagnosing testicular mesothelioma (mesothelioma of the tunica vaginalis) is notoriously difficult. The symptoms are vague, often mimic benign conditions, and standard imaging or fluid tests rarely provide definitive answers. As a result, the diagnosis is typically made only after surgery—most often during or following an orchiectomy.

Imaging and Diagnostic Challenges

• Ultrasound is often the first diagnostic tool used for scrotal swelling or hydrocele. It may show:

  • Irregular tunical thickening

  • Papillary excrescences or soft-tissue masses

  • Multinodular or cystic lesions

  However, these findings are not specific to mesothelioma and may resemble hydrocele, epididymitis, or testicular tumors. In some cases, sonography has falsely suggested rare conditions like splenogonadal fusion, leading to delays in diagnosis.

• Color Doppler ultrasound, which evaluates blood flow, may help identify decreased vascularity in mesotheliomatous tissue compared to normal testicular parenchyma—but interpretation remains difficult and not standardized.

• Fine Needle Aspiration (FNA) of hydrocele fluid is often attempted but rarely yields a definitive diagnosis. The mesothelioma cells may not shed into the fluid in detectable numbers, and cytology reports are frequently negative or inconclusive.

• Ultrasound-guided FNA of visible masses, rather than just hydrocele fluid, may improve diagnostic accuracy but is not commonly done unless there's already suspicion of malignancy.

• CT scans are more helpful in advanced stages, particularly to:

  • Detect retroperitoneal, pelvic, or mediastinal lymph node metastases

  • Evaluate possible spread to the lungs or peritoneum

  • Monitor for recurrence or progression

Why Diagnosis Is Often Missed

Most patients with testicular mesothelioma present with hydrocele of unknown origin or a painless scrotal mass. Because these symptoms overlap with far more common and benign conditions, doctors often assume more common conditions such as: inguinal hernia, spermatocele, epididymitis, testicular torsion, or primary testicular cancer. This leads to repeated aspirations, delayed surgeries, or conservative management. In fact, correct preoperative diagnosis is extremely rare unless there is:

• A strong clinical suspicion

• A history of occupational asbestos exposure

• A refractory hydrocele that keeps recurring despite drainage or hydrocelectomy

Even modern imaging and biopsy techniques often fail to definitively diagnose mesothelioma before surgery. In most documented cases, the diagnosis is made histologically, based on tissue obtained during radical inguinal orchiectomy and with immunohistochemistry (IHC) confirming mesothelial markers like calretinin and CK5/6.

How is testicular mesothelioma treated?

The treatment of testicular mesothelioma (mesothelioma of the tunica vaginalis) typically begins with surgery, followed by careful consideration of additional therapies based on stage, recurrence risk, and patient health. Due to the rarity of this cancer, no formal treatment guidelines exist, but consistent patterns have emerged from decades of case studies and national registry data.

Surgery: The Primary Treatment

• The standard initial treatment is a radical inguinal orchiectomy — surgical removal of the affected testicle and spermatic cord.

  • This approach is essential not only to remove the tumor but also to establish a definitive diagnosis via pathological analysis.

• A limited, conservative surgery (such as local excision or hydrocelectomy alone) is strongly discouraged, as it often results in rapid recurrence.

In the large-scale Marinaccio study, surgery was the initial treatment in nearly all cases, though the details of surgical margins and lymph node evaluation varied.

Recurrence and Secondary Surgeries

• Recurrence is common, occurring in up to 60% of cases within 2 years—even when initial surgery is radical.

• Recurrent disease may present as scrotal nodules, inguinal lymphadenopathy, or retroperitoneal spread.

• Reoperations may involve:

  • Hemiscrotectomy (removal of part or all of the scrotum)

  • Lymph node dissection (inguinal or retroperitoneal)

  • Debulking of metastatic lesions

Chemotherapy

• Chemotherapy is often used after recurrence or when metastatic disease is identified.

• The most common regimens include pemetrexed + cisplatin, borrowed from pleural mesothelioma treatment protocols.

• However, chemotherapy has limited effectiveness in this cancer subtype, especially in older patients or those with sarcomatoid histology.

In the Bisceglia case study, the patient underwent multiple surgeries over several years, followed by systemic chemotherapy when nodal and lung metastases developed. Despite treatment, disease eventually progressed.

Radiation Therapy

• Radiation therapy has occasionally been used for palliative purposes—such as controlling chest wall or skin metastases causing discomfort or edema.

• Like chemotherapy, its effectiveness is limited, and it is not part of routine first-line management.

For the latest updates on treatment options, visit our prognosis and treatment page for testicular mesothelioma.

What is the prognosis for testicular mesothelioma?

Testicular mesothelioma—also called mesothelioma of the tunica vaginalis—is rare, but often aggressive. Prognosis depends on several key factors, including how early the disease is detected, whether it has spread beyond the scrotum, and the patient’s age and general health.

Survival Outlook

• According to the largest national study to date (Marinaccio et al., 2020), the median survival for men with testicular mesothelioma was 33.0 months, or about 2.75 years.

• In contrast, pleural mesothelioma (which affects the lungs) typically has a median survival of 12–21 months, making testicular mesothelioma one of the more survivable types of this cancer.

• Still, long-term survival is uncommon. Some patients survive more than 5 years, but many do not—especially if the disease is not caught early.

Why Orchiectomy Isn’t Always Enough

A common question is: “If you remove the affected testicle, isn’t the cancer gone?”

Unfortunately, no. Even when the tumor appears to be confined to the testicle, the disease often extends beyond the visible mass:

• Microscopic spread can already be present in nearby tissues, such as the epididymis, spermatic cord, or scrotal wall.

• The tunica vaginalis is a thin mesothelial layer that connects back into the abdominal cavity via the inguinal canal, providing a pathway for cancer to migrate or recur.

• Tumor cells may already have seeded lymph nodes (especially inguinal or retroperitoneal nodes) before diagnosis—even when imaging is negative at first.

• In the largest clinical reviews, recurrence after orchiectomy occurred in up to 60% of cases, usually within two years.

So while orchiectomy is necessary, it’s not curative on its own in many cases. That’s why close monitoring and sometimes additional treatment is so important.

Factors That Influence Prognosis

Several factors have been shown to influence outcomes:

Testicular mesothelioma is not necessarily fatal, but it requires lifelong follow-up. Radical orchiectomy may remove the visible tumor, but it does not guarantee cure, due to the cancer’s microscopic spread and high rate of recurrence.

What are my legal options if I’ve been diagnosed with testicular mesothelioma?

Despite its rarity, testicular mesothelioma is legally treated the same as other types (like pleural or peritoneal mesothelioma) when it comes to asbestos-related compensation.

Asbestos Trust Funds

Dozens of asbestos companies filed for bankruptcy and were required by law to set up asbestos trust funds to compensate victims. These trusts:

• Accept all types of mesothelioma, including testicular

• Only require proof of exposure to qualifying asbestos products and a medical diagnosis

• Pay claimants based on scheduled values, often ranging from tens of thousands to hundreds of thousands of dollars, depending on the trust

Your claim may qualify for multiple trusts if you were exposed to asbestos through different jobs or products.

VA Benefits for Veterans

If you served in the military and were exposed to asbestos, you may be eligible for VA disability compensation or special monthly compensation. The U.S. Department of Veterans Affairs recognizes all forms of mesothelioma, including testicular, as compensable asbestos-related illnesses—as long as military exposure can be established.

Social Security Disability (SSD)

Mesothelioma of any type—including testicular—is on the Social Security Administration’s list of Compassionate Allowances, meaning:

• Your claim will be fast-tracked

• A confirmed diagnosis is usually enough to qualify for full disability benefits

This applies whether you’re under retirement age or unable to work due to the disease or treatment.

Personal Injury or Wrongful Death Lawsuits

Historically, some testicular mesothelioma claims faced skepticism in court due to limited scientific data linking the disease to asbestos. That has now changed. The landmark 2020 case–control study published in the Scandinavian Journal of Work, Environment & Health provided the first statistical proof that asbestos exposure causes testicular mesothelioma. This means:

• Courts are now more likely to accept expert testimony linking asbestos exposure to testicular mesothelioma

• Jury verdicts and settlements are likely to improve as defense arguments become less credible

📞 Call 833-4-ASBESTOS or contact us online for a free, confidential consultation about your legal options.