Mesothelioma & Asbestos Glossary

Amosite, commonly known as brown asbestos, is an amphibole mineral fiber that was the second most commonly used type of asbestos in commercial applications. Its straight, needle-like fibers are more durable in the body than chrysotile and are associated with a high risk of mesothelioma and lung cancer.

Asbestos abatement is the professional process of identifying, removing, encapsulating, or otherwise managing asbestos-containing materials in buildings to eliminate or reduce the risk of fiber release. Abatement must be performed by licensed contractors following strict EPA and OSHA regulations to protect workers and building occupants.

An asbestos trust fund is a court-established financial reserve created during or after a company's bankruptcy to compensate current and future victims of asbestos exposure. More than 60 active trusts collectively hold over $30 billion in assets. Trust fund claims do not require a lawsuit and can be filed alongside other legal actions.

Asbestosis is a chronic, progressive lung disease caused by the inhalation of asbestos fibers, which cause scarring (fibrosis) of lung tissue. Unlike mesothelioma, asbestosis is not cancer, but it permanently reduces lung function and indicates significant asbestos exposure that increases cancer risk.

A bankruptcy trust is a fund established under Section 524(g) of the U.S. Bankruptcy Code when an asbestos-liable company undergoes Chapter 11 reorganization. The trust assumes the company's asbestos liabilities and pays claims from current and future victims according to court-approved payment criteria and schedules.

A biopsy is a medical procedure in which a tissue sample is extracted from the body for pathological examination under a microscope. In mesothelioma diagnosis, biopsy is the only definitive way to confirm the disease, determine the cell type, and distinguish mesothelioma from other cancers.

Biphasic mesothelioma contains both epithelioid and sarcomatoid cells within the same tumor, accounting for 20–35% of cases. Prognosis and treatment response depend on the ratio of cell types present. Tumors with a higher proportion of epithelioid cells respond better to treatment and carry a more favorable outlook.

Staging is the standardized system for classifying the extent of cancer spread in the body, using stages I through IV. For pleural mesothelioma, the TNM staging system evaluates tumor size (T), lymph node involvement (N), and distant metastasis (M). Stage determines treatment eligibility, prognosis, and clinical trial options.

Chemotherapy is a cancer treatment that uses cytotoxic drugs to kill rapidly dividing cancer cells or slow their growth. The standard first-line chemotherapy regimen for mesothelioma combines pemetrexed (Alimta) with cisplatin or carboplatin, typically administered in 21-day cycles for 4–6 cycles.

Chrysotile, commonly known as white asbestos, is a serpentine mineral fiber that accounts for approximately 95% of all asbestos used commercially in the United States. Despite industry claims of lower toxicity compared to amphibole fibers, chrysotile is a confirmed carcinogen and a proven cause of mesothelioma, lung cancer, and asbestosis.

Cisplatin is a platinum-based chemotherapy drug used as a first-line treatment for mesothelioma in combination with pemetrexed. It works by cross-linking DNA strands within cancer cells, preventing replication and triggering cell death. Cisplatin has been a cornerstone of cancer treatment since its FDA approval in 1978.

A class action is a type of lawsuit in which a group of plaintiffs with similar injuries and legal claims sue one or more defendants collectively. While class actions are common in many areas of law, mesothelioma and asbestos cases are almost always filed as individual lawsuits because each patient's exposure history, diagnosis, and damages are unique.

A clinical trial is a research study that tests new treatments, drug combinations, or therapeutic approaches in human patients under controlled conditions. For mesothelioma patients, clinical trials provide access to cutting-edge therapies — including novel immunotherapies, gene therapies, and targeted agents — that are not yet widely available.

A contingency fee is an attorney payment arrangement in which the lawyer receives a percentage of the client's recovery (settlement or verdict) as their fee. If the case is unsuccessful, the client owes no attorney fees. This structure allows mesothelioma patients to pursue legal claims without any upfront costs.

Crocidolite, commonly known as blue asbestos, is an amphibole mineral fiber considered the most dangerous type of asbestos due to its extremely thin, needle-like fibers. These fibers are easily inhaled, penetrate deep into lung tissue, and are the most resistant to biological clearance, resulting in the highest mesothelioma risk per fiber exposure.

A deposition is a sworn, out-of-court testimony given by a witness or party during the discovery phase of litigation. In mesothelioma cases, depositions are critical for recording the patient's detailed asbestos exposure history, identifying responsible companies, and preserving testimony that can be used at trial.

The discovery rule is a legal principle that delays the start of the statute of limitations until the plaintiff knew or reasonably should have known about their injury. For mesothelioma, this means the filing clock begins at the date of diagnosis, not the date of asbestos exposure — which may have occurred 20–50 years earlier.

Epithelioid mesothelioma is the most common cell type, found in 50–70% of all mesothelioma cases. Epithelioid cells are uniform and well-defined, grow more slowly than other cell types, and respond best to treatment. Patients with epithelioid histology have the most favorable prognosis among all mesothelioma cell types.

Extrapleural pneumonectomy is a radical surgical procedure for pleural mesothelioma that removes the affected lung, the pleural lining, the diaphragm on the affected side, and the pericardium (heart sac). It is one of the most extensive thoracic surgeries performed and is reserved for select patients with early-stage disease.

Friable asbestos refers to any asbestos-containing material that can be crumbled, pulverized, or reduced to powder by hand pressure. Friable materials release asbestos fibers into the air easily, creating the highest risk of inhalation exposure. Spray-on insulation, pipe lagging, and acoustical plaster are common friable asbestos products.

Immunohistochemistry (IHC) is a laboratory technique that uses antibodies to detect specific protein markers in tissue samples. In mesothelioma diagnosis, IHC is essential for distinguishing mesothelioma from lung adenocarcinoma and other cancers that can appear similar under the microscope, and for identifying the specific cell type.

Immunotherapy is a type of cancer treatment that harnesses the body's own immune system to recognize and attack cancer cells. In October 2020, the FDA approved the combination of nivolumab (Opdivo) and ipilimumab (Yervoy) as the first immunotherapy for unresectable pleural mesothelioma, marking a major treatment advance.

The latency period is the time between initial asbestos exposure and the appearance of mesothelioma symptoms or diagnosis. For mesothelioma, this period typically ranges from 20 to 50 years, with an average of 30–40 years. This extended latency is one reason the disease continues to be diagnosed decades after asbestos use declined.

Mesothelioma is a rare and aggressive form of cancer that develops in the mesothelial lining of the lungs, abdomen, or heart. It is caused almost exclusively by exposure to asbestos fibers, with no safe level of exposure established. Approximately 3,000 new cases are diagnosed in the United States each year.

Metastasis is the process by which cancer cells spread from the original (primary) tumor to distant sites in the body through the bloodstream or lymphatic system. In mesothelioma, metastasis to the lymph nodes, liver, bones, or contralateral lung typically indicates advanced disease and limits surgical treatment options.

Multidistrict litigation is a federal legal procedure that consolidates similar civil cases filed in different federal districts into a single court for coordinated pretrial proceedings. Many asbestos and mesothelioma cases are handled through MDL to increase efficiency while preserving each plaintiff's right to an individual trial.

Nivolumab (brand name Opdivo) is an immune checkpoint inhibitor that blocks the PD-1 protein on T cells, allowing the immune system to recognize and attack cancer cells. In combination with ipilimumab, it is FDA-approved as a first-line treatment for unresectable malignant pleural mesothelioma.

Non-friable asbestos refers to asbestos-containing materials in which the fibers are bound within a solid matrix (such as cement, vinyl, or resin) and cannot be crumbled by hand pressure under normal conditions. While less immediately hazardous than friable materials, non-friable asbestos becomes dangerous when cut, drilled, sanded, or otherwise mechanically disturbed.

Occupational exposure refers to asbestos exposure occurring in the workplace, which is the most common route of exposure leading to mesothelioma. Industries with the highest historical exposure rates include construction, shipbuilding, automotive manufacturing, power generation, oil refining, and military service, particularly the U.S. Navy.

Pemetrexed (brand name Alimta) is an antifolate chemotherapy drug that is the backbone of the standard first-line mesothelioma chemotherapy regimen. Approved by the FDA in 2004 for use with cisplatin, pemetrexed works by disrupting folate-dependent metabolic processes essential for cancer cell DNA synthesis and replication.

Pericardial mesothelioma is the rarest form of mesothelioma, accounting for less than 1% of all cases. It develops in the pericardium, the protective sac surrounding the heart. Due to its rarity and location, it is frequently diagnosed postmortem and carries the poorest prognosis of all mesothelioma types.

Peritoneal mesothelioma develops in the peritoneal lining of the abdominal cavity and accounts for 15–20% of all mesothelioma cases. It is caused by asbestos fibers that are swallowed or migrate from the lungs to the abdomen. Symptoms include abdominal pain, swelling, and unexplained weight loss.

A personal injury claim is a legal action filed by a living mesothelioma patient seeking compensation for damages caused by asbestos exposure. These claims hold negligent companies financially responsible for medical expenses, lost wages, pain and suffering, and diminished quality of life resulting from the disease.

Pleural effusion is an abnormal accumulation of fluid between the two layers of the pleural membrane surrounding the lungs. It occurs in approximately 90% of pleural mesothelioma cases and is often the first clinical sign of the disease. The fluid causes chest pressure, shortness of breath, and persistent cough.

Pleural mesothelioma is the most common type of mesothelioma, accounting for approximately 80% of all cases. It develops in the pleural lining that surrounds the lungs and is caused by inhaled asbestos fibers that become lodged in the pleural tissue, triggering malignant cell growth over decades.

Pleural plaques are localized areas of calcified fibrous thickening on the pleural membrane caused by asbestos exposure. They are the most common radiographic finding in asbestos-exposed individuals and are not cancerous. However, their presence confirms prior asbestos exposure and signals potential risk for more serious asbestos diseases.

Pleural thickening is a condition in which the pleural membrane becomes scarred and thickened due to asbestos fiber irritation. Unlike localized pleural plaques, diffuse pleural thickening can restrict lung expansion and cause significant breathing impairment. It is a recognized marker of substantial asbestos exposure.

Pleurectomy/decortication is a lung-sparing surgical procedure for pleural mesothelioma that removes the pleural lining and all visible tumor while preserving the underlying lung. It may include removal of the diaphragm and pericardium (extended P/D). It offers a less radical alternative to EPP with lower surgical morbidity.

Pleurodesis is a medical procedure that permanently seals the pleural space to prevent recurrent fluid buildup (pleural effusion). A sclerosing agent — typically sterile talc — is introduced into the pleural space, causing the two pleural layers to adhere together and eliminating the space where fluid accumulates.

Prognosis is the expected course and outcome of a disease based on clinical evidence. For mesothelioma, prognosis depends on the cancer stage at diagnosis, cell type, patient age and overall health, and treatment response. The overall median survival is 12–21 months, though individual outcomes vary significantly.

Radiation therapy uses high-energy X-rays or protons to kill cancer cells and shrink tumors. In mesothelioma treatment, radiation is most commonly used as an adjuvant therapy after surgery to target remaining cancer cells, or as a palliative treatment to reduce pain and control symptoms in advanced disease.

Sarcomatoid mesothelioma is the rarest and most aggressive cell type, accounting for 10–20% of cases. Sarcomatoid cells are spindle-shaped and irregular, grow rapidly, and are more resistant to standard treatments. This cell type carries the poorest prognosis of all mesothelioma histological subtypes.

Secondary exposure, also known as take-home exposure, occurs when a person is exposed to asbestos fibers carried home on the clothing, hair, skin, or belongings of someone who worked directly with asbestos. Spouses and children of asbestos workers are the most common victims of secondary exposure, and this route has caused documented cases of mesothelioma.

A settlement is a negotiated resolution of a lawsuit in which the defendant agrees to pay the plaintiff an agreed-upon amount in exchange for the plaintiff dropping their legal claims. The majority of mesothelioma lawsuits resolve through settlement rather than proceeding to a trial verdict, often resulting in faster compensation.

The statute of limitations is the legal deadline by which a lawsuit must be filed. For mesothelioma cases, this period varies by state, typically ranging from 1 to 6 years from the date of diagnosis or discovery of the disease. Missing this deadline permanently bars a patient or their family from filing a legal claim.

Thoracentesis is a medical procedure in which a needle is inserted through the chest wall into the pleural space to remove excess fluid. It serves both diagnostic and therapeutic purposes in mesothelioma — the drained fluid can be tested for cancer cells while the procedure itself provides immediate relief from breathing difficulty.

Transite is an asbestos-cement building product consisting of asbestos fibers (typically chrysotile) mixed with Portland cement. Manufactured primarily from the 1930s through the 1980s, transite was widely used for siding, roofing, pipes, ducts, and panels in residential, commercial, and industrial construction throughout the United States.

A verdict is the formal decision rendered by a judge or jury at the conclusion of a trial. In mesothelioma cases, jury verdicts can result in substantial compensatory damages (covering medical costs, lost income, pain and suffering) and, in some cases, punitive damages intended to punish defendants for egregious conduct.

Vermiculite is a naturally occurring mineral used in insulation, gardening, and construction products. Vermiculite itself is not asbestos, but the world's largest vermiculite mine — in Libby, Montana, operated by W.R. Grace — was contaminated with tremolite asbestos, resulting in widespread exposure that caused hundreds of asbestos-related deaths.

A wrongful death lawsuit is a legal action filed by the surviving family members or estate of a person who died as a result of another party's negligence or wrongful conduct. In mesothelioma cases, these lawsuits hold asbestos companies accountable for the exposure that caused the patient's fatal disease.