Types of Mesothelioma
The term “mesothelioma” generally refers to a type of cancer that affects the cells of the mesothelium, a membrane that lines and protects organs in the chest and in the abdominal cavity. For this reason, mesothelioma can occur in different places in the body.
The mesothelium has different names depending on the organs it surrounds. The pleura is the membrane that lines the lungs. The peritoneum surrounds the organs within the abdominal cavity. The pericardium envelops the heart, while the tunica vaginalis coats the testicles.
About two-thirds of all mesothelioma patients have the disease in the pleural mesothelium (known as Malignant Pleural Mesothelioma, or MPM). In one-third of patients, the disease develops in the abdomen (peritoneum). Mesotheliomas of the membranes that surround the heart or the testicles are very rare.
MPM is primarily a locally invasive cancer, but it may spread to distant organs if the disease has advanced. Usually only one side of the chest is involved, but there is no evidence suggesting a preference for either side. Fewer than five percent of patients have the disease on both sides.
Subtypes of MPM
According to the microscopic appearance of the tumor, three distinct subtypes of MPM may be defined: (1) epithelial, (2) sarcomatoid, and (3) mixed type of disease.
In general, the epithelial subtype is associated with the best prognosis or outcome while the sarcomatoid type is associated with the worst. Moreover, the histologic subtype is a critical variable affecting the design of the most appropriate treatment plan.
Consequently, at MTC, a dedicated and experienced pathologist will conduct an extensive evaluation of multiple tissue samples from the different areas of the tumor in order to confirm the exact disease subtype. In fact, this is so critical that even if the patient comes in with a preliminary diagnosis conducted elsewhere, our expert pathologists will always reanalyze the samples in order to confirm the diagnosis and subtyping of MPM.
Epithelial malignant mesothelioma with a tubular, infiltrative growth pattern invading into skeletal muscle.
Tumor cells with a tubulopapillary pattern invade into the adipose tissue.