Mesothelioma Types

Mesothelioma Types Overview
Classification by location and cell type
Pleural	~75% of cases
Peritoneal	~20% of cases
Pericardial	~1% of cases
Testicular	<1% of cases
Best Prognosis	Epithelioid cell type
Annual US Cases	~3,000 diagnoses
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Mesothelioma Types: Complete Guide to Location, Cell Type, Staging, and Prognosis (2026)

Executive Summary

Mesothelioma is classified by two primary factors: anatomical location (where the cancer develops) and cell type (histology)—both critically important for determining treatment options, prognosis, and eligibility for clinical trials. Approximately 3,000 Americans are diagnosed with mesothelioma annually, with pleural mesothelioma (affecting the lung lining) accounting for roughly 75% of cases, peritoneal mesothelioma (abdominal lining) representing about 20%, and pericardial (heart lining) and testicular types comprising the remaining rare cases. Cell type classification—epithelioid, sarcomatoid, or biphasic (mixed)—significantly impacts survival, with epithelioid patients experiencing median survival of 12-24 months compared to 6-12 months for sarcomatoid. Understanding your specific mesothelioma type is essential for pursuing optimal treatment at specialized treatment centers and maximizing compensation through asbestos trust funds and legal claims.

Key Facts

Key Facts: Mesothelioma Types

Annual US Diagnoses: Approximately 3,000 new mesothelioma cases diagnosed each year Primary Cause: 70-80% of cases linked to occupational or environmental asbestos exposure Average Latency: 20-50 years between first asbestos exposure and diagnosis (mean 40 years) Pleural Mesothelioma: 75% of all cases; develops in lung lining (pleura) Peritoneal Mesothelioma: 20% of cases; develops in abdominal lining (peritoneum) Pericardial Mesothelioma: ~1% of cases; affects heart lining; often diagnosed posthumously Testicular Mesothelioma: <1% of cases; rarest form; best prognosis among types Epithelioid Cell Type: 50-70% of cases; most treatable; best prognosis Sarcomatoid Cell Type: 10-20% of cases; most aggressive; poorest prognosis Biphasic Cell Type: 20-35% of cases; mixed epithelioid and sarcomatoid; prognosis depends on ratio 5-Year Survival: 10-12% overall; up to 20%+ for early-stage epithelioid with aggressive treatment

What Are the Four Types of Mesothelioma by Location?

Mesothelioma develops in the mesothelium—a thin membrane lining the body's internal cavities and organs. The specific location determines the type, symptoms, treatment options, and prognosis.

Pleural Mesothelioma (Lung Lining) – 75% of Cases

Pleural Mesothelioma develops in the pleura, the two-layered membrane surrounding the lungs. It is the most common form, representing approximately 75% of all mesothelioma diagnoses. See Pleural Mesothelioma for the comprehensive treatment guide including CheckMate 743 immunotherapy data, MARS 2 trial findings, CAR-T therapy, and current survival statistics.

How It Develops: When asbestos fibers are inhaled, they can lodge in the pleura and cause chronic inflammation and scarring over decades. This cellular damage eventually leads to cancerous tumor formation in the pleural lining.

Common Symptoms:

• Persistent dry cough or coughing up blood
• Shortness of breath (dyspnea)
• Chest pain, often worsening with deep breathing
• Unexplained weight loss
• Fatigue and weakness
• Pleural effusion (fluid buildup between lung and chest wall)
• Lumps under the skin on the chest

Treatment Options:

• Surgery: Extrapleural pneumonectomy (EPP), pleurectomy/decortication (P/D)
• Chemotherapy: Pemetrexed (Alimta) plus cisplatin or carboplatin
• Radiation: Often combined with surgery (multimodal therapy)
• Immunotherapy: Opdivo (nivolumab) plus Yervoy (ipilimumab) FDA-approved 2020
• Tumor Treating Fields: Optune Lua device approved 2019

Prognosis:

• Median survival: 12-21 months with treatment
• 5-year survival: 10-12% overall; up to 20%+ for early-stage with surgery
• Best outcomes: Stage I-II epithelioid treated with multimodal therapy

"Pleural mesothelioma patients today have more treatment options than ever before. The 2020 FDA approval of immunotherapy and ongoing clinical trials offer hope that wasn't available even five years ago. Getting to a specialized treatment center quickly is critical."

— David Foster, Patient Advocate, Danziger & De Llano

Peritoneal Mesothelioma (Abdominal Lining) – 20% of Cases

Peritoneal Mesothelioma develops in the peritoneum, the membrane lining the abdominal cavity and surrounding organs including the stomach, liver, spleen, and intestines. See Peritoneal Mesothelioma for the comprehensive guide including CRS/HIPEC outcomes (41-59% 5-year survival), PIPAC therapy, and emerging immunotherapy data.

How It Develops: Asbestos fibers can reach the peritoneum through:

• Swallowing inhaled fibers that were cleared from the respiratory tract
• Migration through the lymphatic system
• Direct ingestion of asbestos-contaminated materials

Common Symptoms:

• Abdominal pain and swelling
• Ascites (fluid accumulation in the abdomen)
• Unexplained weight loss
• Loss of appetite
• Nausea and vomiting
• Bowel obstruction
• Changes in bowel habits
• Abdominal masses

Treatment Options:

• HIPEC: Heated Intraperitoneal Chemotherapy—surgery combined with heated chemotherapy wash
• Cytoreductive Surgery (CRS): Removing visible tumors from abdominal cavity
• Systemic Chemotherapy: Pemetrexed plus platinum-based drugs
• Immunotherapy: Emerging treatment option showing promise

Prognosis:

• Median survival: 12-21 months with standard treatment
• With HIPEC: 5-year survival rates of 40-50% reported at specialized centers
• Best outcomes: Epithelioid cell type with complete cytoreduction

✓ Treatment Advance: HIPEC (heated intraperitoneal chemotherapy) has dramatically improved peritoneal mesothelioma outcomes. Select patients treated with CRS and HIPEC at specialized centers have achieved 5-year survival rates exceeding 50%—far better than historical expectations.

Pericardial Mesothelioma (Heart Lining) – ~1% of Cases

Pericardial mesothelioma is an extremely rare form developing in the pericardium—the thin sac surrounding the heart. It represents approximately 1% of all mesothelioma diagnoses and is frequently discovered posthumously during autopsy.

How It Develops: The exact mechanism is unclear, but theories include:

• Asbestos fibers traveling through the bloodstream to the heart
• Migration through the lymphatic system
• Some cases may have genetic components

Common Symptoms:

• Chest pain
• Difficulty breathing
• Heart palpitations and irregular heartbeat
• Pericardial effusion (fluid around the heart)
• Cardiac tamponade (pressure on the heart from fluid)
• Fatigue
• Night sweats

Treatment Challenges:

• Location near the heart limits surgical options
• Often diagnosed at advanced stages
• Treatment focuses primarily on symptom management
• Pericardiectomy (removal of pericardium) may be attempted in select cases
• Chemotherapy and radiation used palliatively

Prognosis:

• Median survival: 6-10 months
• Very limited treatment options due to proximity to vital cardiac structures
• Most cases diagnosed posthumously

Testicular Mesothelioma (Tunica Vaginalis) – <1% of Cases

Testicular mesothelioma is the rarest form, developing in the tunica vaginalis—the membrane surrounding the testes. Fewer than 100 cases have been documented in medical literature.

How It Develops: The pathway of asbestos fibers to the tunica vaginalis remains poorly understood. Some cases have no documented asbestos exposure, suggesting possible genetic or other environmental factors.

Common Symptoms:

• Painless testicular lump or mass
• Hydrocele (fluid accumulation in scrotum)
• Scrotal swelling
• Often discovered incidentally during hernia repair or hydrocele surgery

Treatment Options:

• Surgery: Radical orchiectomy (testicle removal) is primary treatment
• Adjuvant therapy: Chemotherapy and/or radiation may follow surgery
• Surveillance: Close monitoring for recurrence

Prognosis:

• Paradoxically the best prognosis among mesothelioma types
• 5-year survival: Approximately 50%
• High recurrence rate (50-60%) requires ongoing surveillance
• Localized nature allows for complete surgical removal in many cases

What Are the Three Cell Types of Mesothelioma?

Beyond anatomical location, mesothelioma is classified by histological cell type—the appearance and behavior of cancer cells under microscopic examination. Cell type significantly impacts treatment response and prognosis.

Epithelioid Mesothelioma – 50-70% of Cases

Epithelioid mesothelioma is the most common and most treatable cell type, accounting for 50-70% of all diagnoses.

Characteristics:

• Cells are uniform, cube-shaped, and clearly defined
• Slower to spread than other types
• Responds best to treatment
• Lower rate of metastasis
• Easier to identify on biopsy

Subtypes of Epithelioid:

• Tubulopapillary: Most common; tube-like structures
• Adenomatoid: Gland-like appearance
• Solid: Dense sheets of cells
• Deciduoid: Large, rounded cells
• Small cell: Smaller uniform cells

Prognosis:

• Median survival: 12-24 months
• Best response to surgery, chemotherapy, and multimodal treatment
• 5-year survival rates approach 20%+ with aggressive treatment at specialized centers

Sarcomatoid Mesothelioma – 10-20% of Cases

Sarcomatoid mesothelioma is the most aggressive and treatment-resistant cell type, representing 10-20% of cases.

Characteristics:

• Cells are spindle-shaped and irregular
• Highly aggressive with rapid growth
• Tends to metastasize quickly
• Resistant to standard treatments
• Can be difficult to distinguish from other cancers

Subtypes of Sarcomatoid:

• Transitional: Evolving from epithelioid characteristics
• Lymphohistiocytoid: Contains inflammatory cells
• Desmoplastic: Dense fibrous tissue; hardest to diagnose

Prognosis:

• Median survival: 6-12 months
• Poor response to standard chemotherapy
• Surgery often not recommended due to aggressive spread
• Clinical trials may offer best hope for novel treatments

Biphasic Mesothelioma – 20-35% of Cases

Biphasic mesothelioma (also called mixed mesothelioma) contains both epithelioid and sarcomatoid cells, representing 20-35% of diagnoses.

Characteristics:

• Contains varying proportions of both cell types
• Behavior depends on the dominant cell type
• More epithelioid = better prognosis
• More sarcomatoid = poorer prognosis
• Requires careful pathological analysis to determine ratio

Diagnostic Importance: Accurate determination of the epithelioid-to-sarcomatoid ratio is critical for:

• Treatment planning
• Surgical candidacy decisions
• Prognosis estimation
• Clinical trial eligibility

Prognosis:

• Median survival: 10-15 months
• Depends heavily on the proportion of each cell type
• Tumors with >50% epithelioid cells respond better to treatment

"Getting an accurate pathology report is crucial. We always recommend patients have their biopsy slides reviewed by a mesothelioma specialist pathologist. The cell type determination affects every treatment decision and can even impact compensation claims."

— Paul Danziger, Founding Partner, Danziger & De Llano

How Is Mesothelioma Staged?

Mesothelioma staging describes how far the cancer has spread and helps determine treatment options. The TNM staging system is most commonly used for pleural mesothelioma.

Stage I (Localized)

Stage IA: Cancer is in the pleura on one side of the chest only Stage IB: Cancer has grown into the diaphragm or lung tissue

• Treatment: Surgery (EPP or P/D) with chemotherapy and/or radiation
• Prognosis: Best outcomes; median survival 21+ months with multimodal treatment

Stage II (Locally Advanced)

Cancer has spread from the pleura to nearby lymph nodes or the lung, diaphragm, or chest wall on the same side.

• Treatment: Surgery may still be possible; chemotherapy and radiation
• Prognosis: Median survival 15-19 months with treatment

Stage III (Advanced)

Cancer has spread more extensively to lymph nodes, chest wall, heart covering, or other structures on the same side of the chest.

• Treatment: Chemotherapy primary; surgery in select cases; radiation for symptom control
• Prognosis: Median survival 12-16 months

Stage IV (Metastatic)

Cancer has spread to distant sites including the other side of the chest, distant lymph nodes, or other organs.

• Treatment: Palliative chemotherapy, immunotherapy, radiation for symptom relief
• Prognosis: Median survival 6-12 months; focus on quality of life

⚠ Early Detection Matters: Stage at diagnosis is the single most important prognostic factor. Workers with known asbestos exposure should undergo regular screening with chest X-rays or CT scans. Early detection can mean the difference between surgical candidacy and palliative care only.

How Is Mesothelioma Diagnosed?

Accurate diagnosis requires multiple steps and should ideally be performed at or confirmed by a specialized mesothelioma treatment center.

Diagnostic Process

1. Imaging Studies:

• Chest X-ray (initial screening)
• CT scan (computed tomography)
• PET scan (positron emission tomography)
• MRI (magnetic resonance imaging)

2. Biopsy (Required for Definitive Diagnosis):

• Thoracoscopy: Camera-assisted biopsy of pleura
• Laparoscopy: Camera-assisted biopsy of peritoneum
• CT-guided needle biopsy: Less invasive option
• Surgical biopsy: Open procedure for difficult cases

3. Pathological Analysis:

• Immunohistochemistry to distinguish from other cancers
• Cell type determination (epithelioid, sarcomatoid, biphasic)
• Second opinion pathology review recommended

4. Blood Tests (Biomarkers):

• Mesothelin (SMRP)
• Osteopontin
• Fibulin-3
• Used for monitoring; not diagnostic alone

Importance of Specialist Review

Mesothelioma can be difficult to distinguish from lung cancer, other metastatic cancers, or benign conditions. Misdiagnosis rates are significant. Always seek:

• Pathology review by mesothelioma-experienced pathologist
• Treatment planning by mesothelioma specialist oncologist or surgeon
• Care at a designated mesothelioma treatment center

What Treatment Options Are Available?

Treatment depends on mesothelioma type, stage, cell type, overall health, and patient preferences.

Surgery

For Pleural Mesothelioma:

• Extrapleural Pneumonectomy (EPP): Removal of affected lung, pleura, diaphragm, and pericardium
• Pleurectomy/Decortication (P/D): Removal of pleura while preserving lung; increasingly preferred

For Peritoneal Mesothelioma:

• Cytoreductive Surgery (CRS): Removal of visible tumors from abdominal cavity
• Combined with HIPEC for best outcomes

Chemotherapy

Standard First-Line:

• Pemetrexed (Alimta) + cisplatin or carboplatin
• Administered intravenously in cycles
• May be given before surgery (neoadjuvant) or after (adjuvant)

For Peritoneal Mesothelioma:

• HIPEC: Heated chemotherapy applied directly to abdominal cavity during surgery

Radiation Therapy

• Intensity-modulated radiation therapy (IMRT)
• Used post-surgically to kill remaining cancer cells
• Palliative radiation to relieve pain and symptoms

Immunotherapy

FDA-Approved (2020):

• Opdivo (nivolumab) + Yervoy (ipilimumab) for unresectable pleural mesothelioma
• First new systemic treatment approved in 16 years
• Checkpoint inhibitors that help immune system attack cancer

Tumor Treating Fields (TTFields)

FDA-Approved (2019):

• Optune Lua device
• Portable device worn on chest delivers electric fields
• Used with chemotherapy for unresectable pleural mesothelioma

Clinical Trials

Ongoing research includes:

• Gene therapy approaches
• CAR T-cell therapy
• New immunotherapy combinations
• Targeted therapies
• Viral therapies

ℹ Clinical Trials: Mesothelioma patients should always ask about clinical trial eligibility. Trials offer access to cutting-edge treatments not yet widely available. The National Cancer Institute maintains a searchable database at clinicaltrials.gov.

What Compensation Is Available for Mesothelioma Patients?

Mesothelioma patients and their families may be entitled to substantial compensation from multiple sources.

Asbestos Trust Funds

Over 60 bankruptcy trusts hold more than $30 billion to compensate asbestos victims:

• Claims do not require proving negligence
• Multiple trust claims can be filed simultaneously
• Processing time: 3-12 months typical

Personal Injury Lawsuits

Lawsuits against asbestos manufacturers and employers:

• Average settlements: $1 million to $1.4 million
• Verdicts can exceed $10 million in egregious cases
• Must be filed within statute of limitations

Veterans Benefits

Veterans with service-related asbestos exposure may qualify for:

• VA disability compensation
• VA healthcare benefits
• Dependency and Indemnity Compensation (DIC) for surviving spouses

Workers' Compensation

May cover:

• Medical treatment costs
• Lost wages
• Disability benefits
• Does not prevent filing trust claims or lawsuits against third parties

⚠ Statute of Limitations Warning: Filing deadlines for mesothelioma claims vary by state—most allow only 1-3 years from diagnosis. Texas allows 2 years from diagnosis or discovery. Do not delay seeking legal consultation after a mesothelioma diagnosis.

Get Help Today

Free Case Evaluation for Mesothelioma Patients If you or a loved one has been diagnosed with any type of mesothelioma, our experienced legal team can help you understand your options for compensation while you focus on treatment. What We Offer: • Free, confidential case evaluation • No upfront costs—we only get paid if you recover compensation • Nationwide representation from experienced mesothelioma attorneys • Help identifying all responsible manufacturers and trust funds Call Today: (866) 222-9990 Request Your Free Case Review →

See Also

• Mesothelioma Symptoms — Early warning signs, diagnostic delays, and biomarker advances
• Mesothelioma Causes & Risk Factors — Asbestos fiber potency, latency periods, and non-asbestos causes
• Pleural Mesothelioma — Comprehensive treatment guide: immunotherapy, MARS 2 trial, CAR-T therapy
• Peritoneal Mesothelioma — CRS/HIPEC outcomes, PIPAC therapy, and emerging treatments
• Secondary Asbestos Exposure — Take-home exposure data, legal landscape, and landmark verdicts
• Mesothelioma Treatment Centers
• Asbestos Trust Funds
• Mesothelioma Settlements
• Statute of Limitations
• Occupational Exposure Index