Types of Mesothelioma


There are 7 types of Mesothelioma discussed here.

Mesothelioma can be categorized based on two primary criteria: location in the body and cellular structure.

Based on Location:

  1. Pleural Mesothelioma: Originates in the pleura, the lining of the lungs. This is the most common type.
  2. Peritoneal Mesothelioma: Originates in the peritoneum, the lining of the abdominal cavity.
  3. Pericardial Mesothelioma: Originates in the pericardium, the lining around the heart.
  4. Tunica Vaginalis Mesothelioma: A rare type that affects the lining surrounding the testicles.

Based on Cellular Structure:

  1. Epithelial (or Epithelioid) Mesothelioma: This is the most common histological subtype. The cells are uniform and resemble normal epithelial cells.
  2. Sarcomatoid Mesothelioma: These cells have a more elongated and irregular shape, resembling fibrous tissue.
  3. Biphasic (or Mixed) Mesothelioma: This subtype contains both epithelial and sarcomatoid cells.

When someone refers to the “types” of mesothelioma, they are typically referring to the location-based classification. However, the cellular subtype can also be crucial for prognosis and treatment decisions.

The 4 Types of Mesothelioma Based on where it Originates:

Based on where it originates in the body, mesothelioma can be categorized into several types, but the three primary types are:

  1. Pleural Mesothelioma: This is the most common type of mesothelioma, accounting for about 75-80% of all cases. It originates in the pleura, which is the thin layer of tissue lining the lungs. Symptoms often include chest pain, persistent cough, shortness of breath, and fluid buildup in the chest cavity (pleural effusion).
  2. Peritoneal Mesothelioma: This form affects the lining of the abdominal cavity, called the peritoneum. It accounts for about 15-20% of all mesothelioma cases. Symptoms might include abdominal pain or swelling, weight loss, nausea, and fluid buildup in the abdomen (ascites).
  3. Pericardial Mesothelioma: This is a rare form that develops in the lining of the heart, known as the pericardium. It accounts for roughly 1% or less of all mesothelioma cases. Symptoms can include chest pain, irregular heartbeats, fluid buildup around the heart (pericardial effusion), and shortness of breath.

In addition to these three primary types, there’s also a very rare type called tunica vaginalis mesothelioma, which affects the lining surrounding the testicles.

3 Mesothelioma Types Based on Cellular Structure:

Let’s delve deeper into each of these histological subtypes:

  1. Epithelial (or Epithelioid) Mesothelioma:
    • Appearance: Under the microscope, epithelioid mesothelioma cells are usually polygonal, with a clear and distinct cellular border. They cluster together and can sometimes have a tubular or microcystic pattern.
    • Prognosis & Treatment: Of the subtypes, epithelioid mesothelioma tends to have the best prognosis. This is partly because these tumors typically respond better to treatment than other subtypes.
  2. Sarcomatoid Mesothelioma:
    • Appearance: These cells are spindle-shaped and often appear more chaotic and disordered under the microscope than epithelioid cells. Sarcomatoid cells can sometimes be mistaken for other types of cancers or benign fibrous tissue, making a correct diagnosis crucial.
    • Prognosis & Treatment: Sarcomatoid mesothelioma is more aggressive and tends to have a poorer prognosis compared to epithelioid mesothelioma. It can be more resistant to treatment, which makes management more challenging.
  3. Biphasic (or Mixed) Mesothelioma:
    • Appearance: As the name suggests, biphasic mesothelioma contains both epithelioid and sarcomatoid cells. The ratio of these cell types can vary between tumors.
    • Prognosis & Treatment: The prognosis for biphasic mesothelioma typically falls between that of epithelioid and sarcomatoid subtypes. The specific prognosis and treatment response often depend on the ratio of the two cell types in the tumor. A tumor with more epithelioid cells may have a better prognosis and response to treatment than one dominated by sarcomatoid cells.

The cellular subtype is determined via biopsy and histopathological examination. Identifying the subtype is crucial for treatment planning since the effectiveness of certain treatments can vary based on the tumor’s cellular characteristics.

It’s important to note that early detection and prompt treatment can play a critical role in managing mesothelioma and improving the patient’s prognosis. If someone has a history of asbestos exposure and begins to exhibit symptoms associated with mesothelioma, they should seek medical evaluation as soon as possible.