Pleural Mesothelioma (Lungs)
Pleural mesothelioma develops in the pleura, the protective lining of the lungs and chest cavity. It is the most common type, accounting for approximately 75% of all mesothelioma cases.
About the Pleura
The pleura consists of two layers:
- Visceral pleura: Inner layer directly covering the lungs
- Parietal pleura: Outer layer lining the chest wall
Between these layers is the pleural space containing a small amount of lubricating fluid that allows the lungs to expand and contract smoothly during breathing.
How It Develops
When asbestos fibers are inhaled, they can become trapped in the pleura. Over decades, these fibers cause chronic inflammation, cellular damage, and eventually malignant transformation. The resulting tumors typically cause:
- Pleural thickening and hardening
- Fluid accumulation (pleural effusion)
- Tumor masses that compress the lung
Symptoms
- Shortness of breath (dyspnea)
- Chest pain, especially when breathing deeply
- Persistent dry cough
- Difficulty swallowing
- Fatigue and unexplained weight loss
- Night sweats and fever
Treatment Options
Treatment depends on cancer stage and patient health:
- Surgery: Extrapleural pneumonectomy (EPP) or pleurectomy with decortication (P/D)
- Chemotherapy: Pemetrexed and cisplatin combination
- Radiation: Targeted therapy post-surgery
- Immunotherapy: Checkpoint inhibitors for advanced cases
Prognosis
Pleural mesothelioma typically has a median survival of 12-21 months, though patients eligible for aggressive multimodal treatment may survive 3+ years. Early-stage patients treated with EPP or P/D combined with chemotherapy have the best outcomes. Learn more about mesothelioma prognosis and life expectancy.
Peritoneal Mesothelioma (Abdomen)
Peritoneal mesothelioma develops in the peritoneum, the protective lining of the abdominal cavity. It is the second most common type, representing approximately 20% of mesothelioma cases.
About the Peritoneum
The peritoneum consists of two layers that cover the abdominal organs and line the abdominal wall:
- Visceral peritoneum: Covers abdominal organs
- Parietal peritoneum: Lines the abdominal wall
The peritoneal cavity between these layers contains a small amount of fluid that lubricates organs and allows them to move smoothly.
How It Develops
Peritoneal mesothelioma may develop through:
- Swallowed asbestos fibers that penetrate the intestinal wall
- Transport of inhaled fibers through the lymphatic system
- Direct migration of fibers from the pleural cavity
The trapped fibers cause chronic inflammation leading to tumor development in the abdominal lining.
Symptoms
- Abdominal pain and discomfort
- Abdominal swelling/distension (ascites)
- Nausea and vomiting
- Changes in bowel habits (constipation or diarrhea)
- Unexplained weight loss
- Loss of appetite/feeling full quickly
- Fatigue and weakness
Treatment Options
Peritoneal mesothelioma has seen significant treatment advances:
- Cytoreductive Surgery (CRS): Removes visible tumors from the abdomen
- HIPEC: Heated Intraperitoneal Chemotherapy delivered during surgery
- Systemic Chemotherapy: For patients not eligible for surgery
- Palliative Procedures: Paracentesis to drain abdominal fluid
Prognosis
Peritoneal mesothelioma generally has a better prognosis than pleural mesothelioma. With CRS/HIPEC treatment, median survival extends to 50+ months, and some patients achieve long-term survival exceeding 5 years. See our life expectancy guide for more details.
Pericardial Mesothelioma (Heart)
Pericardial mesothelioma develops in the pericardium, the protective sac surrounding the heart. It is extremely rare, accounting for less than 1% of all mesothelioma cases.
About the Pericardium
The pericardium is a double-layered sac containing lubricating fluid that:
- Protects the heart from infection and inflammation
- Prevents the heart from over-expanding
- Lubricates the heart's movement within the chest
How It Develops
The exact mechanism is not fully understood due to the rarity of this type. Possible pathways include:
- Migration of inhaled asbestos fibers through the bloodstream
- Direct extension from pleural mesothelioma
- Lymphatic spread
Symptoms
Symptoms relate to cardiac function and chest discomfort:
- Chest pain (often sharp or pressure-like)
- Irregular heartbeat (arrhythmia)
- Shortness of breath, especially when lying down
- Heart murmur
- Pericardial effusion (fluid around the heart)
- Fatigue and weakness
- Cough
Diagnosis Challenges
Pericardial mesothelioma is extremely difficult to diagnose because:
- Symptoms mimic more common heart conditions
- Most doctors never encounter a case
- Imaging can be inconclusive
- Biopsy carries risks due to proximity to the heart
Diagnosis often occurs incidentally during surgery or autopsy. Learn more about the diagnosis process and getting a second opinion.
Treatment Options
Treatment is challenging due to the tumor location:
- Pericardiectomy: Surgical removal of the pericardium (rarely possible)
- Pericardiocentesis: Draining fluid to relieve pressure
- Chemotherapy: Limited effectiveness but may slow progression
- Radiation: Rarely used due to heart damage risk
- Palliative care: Focus on symptom management
Prognosis
Pericardial mesothelioma has the poorest prognosis of all types, with median survival typically ranging from 6 weeks to 15 months. The aggressive nature and difficult location make treatment extremely challenging.
Testicular Mesothelioma
Testicular mesothelioma develops in the tunica vaginalis, the lining surrounding the testes. It is the rarest form of mesothelioma, representing less than 1% of cases.
About the Tunica Vaginalis
The tunica vaginalis is a serous membrane derived from the peritoneum during fetal development that surrounds each testis, providing protection and lubrication.
How It Develops
The exact mechanism of development is unclear due to the rarity of this type. The tunica vaginalis shares embryonic origins with the peritoneum, which may explain the connection.
Symptoms
- Painless scrotal mass or swelling
- Hydrocele (fluid accumulation around testis)
- Testicular pain (less common)
- Scrotal enlargement
Diagnosis
Testicular mesothelioma is often diagnosed incidentally during surgery for suspected hernia or hydrocele. Ultrasound may reveal abnormalities, but definitive diagnosis requires tissue biopsy.
Treatment Options
- Radical Orchiectomy: Surgical removal of the affected testis and spermatic cord
- Hemiscrotectomy: Removal of scrotal tissue in advanced cases
- Chemotherapy: Adjuvant chemotherapy may be recommended
- Radiation: Sometimes used for local control
Prognosis
Despite its rarity, testicular mesothelioma often has a better prognosis than other types when treated early. With radical orchiectomy, many patients achieve long-term survival. However, recurrence is common and can occur years after initial treatment.
Cell Type Classification
In addition to the anatomical types above, mesothelioma is also classified by cell type, which affects treatment response and outcomes:
The Three Cell Types
- Epithelioid mesothelioma: The most common (50-70% of cases), with the best treatment response and prognosis
- Sarcomatoid mesothelioma: Less common (10-15%), with aggressive behavior and poor treatment response
- Biphasic mesothelioma: A mixture of epithelioid and sarcomatoid cells (20-30%), with prognosis depending on the cell ratio
Cell type is determined through tissue biopsy and microscopic analysis. The ratio of cell types significantly influences staging, treatment options, and prognosis.
Mesothelioma Types Comparison
| Type | Frequency | Primary Symptoms | Median Survival |
|---|---|---|---|
| Pleural | ~75% | Chest pain, shortness of breath, cough | 12-21 months |
| Peritoneal | ~20% | Abdominal pain, swelling, digestive issues | 50+ months (with CRS/HIPEC) |
| Pericardial | <1% | Chest pain, irregular heartbeat, breathing difficulty | 6 weeks - 15 months |
| Testicular | <1% | Scrotal mass, swelling | Good with early surgery |
Frequently Asked Questions About Types
Can you have more than one type of mesothelioma?
While rare, some patients develop mesothelioma in multiple locations, particularly pleural and peritoneal mesothelioma occurring together or sequentially. This may happen through lymphatic spread or transport of asbestos fibers between body cavities.
Which type of mesothelioma has the best prognosis?
Peritoneal mesothelioma treated with cytoreductive surgery and HIPEC generally has the best prognosis, with median survival extending to 50+ months. Testicular mesothelioma also has relatively good outcomes when treated early with surgery. Pleural mesothelioma prognosis varies widely based on stage and treatment.
Are the symptoms different for each type?
Yes, symptoms correspond to the affected body area. Pleural mesothelioma causes respiratory symptoms (cough, chest pain, shortness of breath), peritoneal causes digestive symptoms (abdominal pain, swelling, nausea), pericardial affects heart function, and testicular presents as scrotal abnormalities.
Is one type more common in certain occupations?
All types are primarily caused by asbestos exposure. However, peritoneal mesothelioma may be slightly more common in occupations with higher rates of asbestos fiber ingestion, such as those involving contaminated food or drink at worksites.
Can the type of mesothelioma change over time?
The primary location doesn't change, but cancer can spread (metastasize) to other areas. Additionally, the cell type (epithelioid, sarcomatoid, biphasic) within a mesothelioma type can influence how the cancer behaves and responds to treatment. Doctors may use biomarkers and tumor markers to help predict how your specific type will respond to treatment.
Unsure Which Type You Have?
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