Testicular mesothelioma is a cancer of the membrane lining the testes. This rare disease, also known as mesothelioma of the tunica vaginalis testis, accounts for less than 1 percent of all mesothelioma cases.
This diagnosis puzzles researchers because most people with mesothelioma can trace their disease to the inhalation or ingestion of asbestos dust.
Most testicular mesothelioma patients, however, have no history of asbestos exposure. There is limited research on testicular mesothelioma because of the rarity of this disease.
Based on the limited number of known cases, men with this type of cancer have a significantly better prognosis than most people with other types of mesothelioma. Most studies report median survival times of about 20 to 23 months, and one patient lived 15 years after diagnosis.
There is no set of symptoms unique to testicular mesothelioma. Many people with this cancer initially receive the wrong diagnosis because doctors mistake it for a more common condition such as a hernia.
The most common symptom is a hydrocele, a buildup of fluid in the scrotum. Men may also notice an abnormal lump inside the scrotum or pain and swelling of the testes. In many cases, testicular mesothelioma is only properly diagnosed during surgery.
The diagnostic process usually starts when someone visits the doctor to discuss a problem with his testicles. The doctor will ask about the patient’s medical history and perform a physical examination.
Next, the doctor will order an ultrasound, a type of imaging scan that is 90 percent accurate for detecting testicular tumors. If a potential tumor is spotted, other imaging scans may be performed to determine the stage of the tumor and whether the cancer has spread.
To confirm the tumor is testicular mesothelioma, doctors can collect a blood sample and look for mesothelioma tumor markers, which are substances released by mesothelioma tumors that help confirm a diagnosis. Tumor markers for testicular mesothelioma include calretinin, cytokeratin 5/6 and Wilms’ tumor gene 1, also known as WT1.
The definitive way of confirming a cancer diagnosis is to perform a biopsy. This involves removing a tissue sample from the tumor and sending it to the lab for testing. Evaluating the sample with a technique called immunohistochemical staining helps doctors determine if the patient has testicular mesothelioma or another disease.
A 2015 study found the most effective surgery for localized testicular mesothelioma is a radical inguinal orchiectomy. This procedure removes the affected testicle and the entire spermatic chord. If the cancer has spread to nearby lymph nodes, doctors will remove them as well with a surgery called lymphadenectomy.
Surgery may be followed by chemotherapy with cisplatin and pemetrexed. Doctors may offer radiation therapy next to kill any remaining cancer cells and prevent the cancer from returning. If the cancer is diagnosed at an early stage, chemotherapy and radiation therapy may not be needed after surgery.
In some cases, testicular mesothelioma is a secondary tumor, with the primary tumor located within the peritoneum, the membrane that lines the abdominal cavity. For situations like this, doctors will have to treat the patient for peritoneal mesothelioma as well.
Peritoneal and testicular mesothelioma are clinically aggressive types of cancer, which means they can spread rapidly. In addition, the testicular type tends to recur within a few years, even in cases where tumors are surgically removed.
Doctors treat peritoneal mesothelioma with similar techniques to those described above — a combination of surgery and chemotherapy. Radiation therapy is often avoided because of the damage it can cause to vital organs in the abdomen. Doctors may also use a special technique called HIPEC, which involves delivering high doses of heated chemotherapy to the abdominal cavity during surgery.
When microscopic asbestos fibers enter the body, they can become lodged in the lining of organs and cause inflammation and genetic damage to cells. Eventually, this can result in the development of mesothelioma as cancerous cells divide abnormally, causing the buildup of fluid and the formation of tumors.
The membrane lining the testes is called the tunica vaginalis. Mesothelioma appears as firm white-yellow nodules on the surface of the tunica vaginalis, and the nodules can eventually encase the contents of the scrotum and cause the tunica vaginalis to thicken.
Mesothelioma usually develops in the lining of the lungs or the abdomen because asbestos fibers have been inhaled or swallowed. Testicular mesothelioma is extremely rare, and doctors do not yet understand how asbestos exposure can cause a primary tumor to develop in the testicles.
Karen Selby joined Asbestos.com in 2009. She is a registered nurse with a background in oncology and thoracic surgery and was the director of a tissue bank before becoming a Patient Advocate at The Mesothelioma Center. Karen has assisted surgeons with thoracic surgeries such as lung resections, lung transplants, pneumonectomies, pleurectomies and wedge resections. She is also a member of the Academy of Oncology Nurse & Patient Navigators.
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