This is the most common form of mesothelioma, occurring in approximately 75 percent of mesothelioma cases. This form of cancer starts in the chest cavity and lungs, and may spread to any organ, including the brain. Symptoms of pleural mesothelioma include persistent pain localized in the chest, severe difficulty breathing, coughing, weight loss, fatigue and fever.
Comprising about 10 to 20 percent of mesothelioma cases, peritoneal mesothelioma starts in the abdominal cavity and may infiltrate the liver, spleen or bowel. Symptoms of peritoneal mesothelioma include pain or swelling in the abdominal region, nausea, vomiting, swelling of the feet, fever, constipation, diarrhea, anemia and unexpected weight loss.
A rare type of mesothelioma, this particular form of the cancer occurs in about 1 percent of mesothelioma victims and starts in the membrane surrounding the heart. Symptoms of pericardial mesothelioma include heart palpitations or murmurs, chest pain, cough, difficulty breathing, fatigue and fever.
Also known as tunica vaginalis mesothelioma, this rare form of mesothelioma affects the inner lining of the sac surrounding the testis and represents anywhere from 0.3% to 5% of all malignant mesothelioma cases. In patients diagnosed with malignant mesothelioma of the tunica vaginalis testis, the main clinical symptom is a painless scrotal mass with fluid buildup (hydrocele).
Mesothelioma Cellular Structure
There are three main types of mesothelioma cells, which are diagnosed based on analysis of the shape and composition of tumor cell samples. Treatment options for all three types are similar, but some clinical trials and treatments target specific cells:
Epithelioid mesothelioma: Representing 50 to 70 percent of mesothelioma cases, epithelioid mesothelioma affects the tube-shaped cells that line and protect internal organs. More research has been performed on epithelioid mesothelioma and it has the best prognosis.
Sarcomatoid mesothelioma: Representing 7 to 20 percent of mesothelioma cases, this form of mesothelioma is considered the most aggressive and is often difficult to diagnose due to the sarcomatoid tumors’ resemblance to other forms of malignant and benign conditions.
Biphasic (mixed) mesothelioma: Representing 20 to 35 percent of mesothelioma cases, biphasic tumors consist of both sarcomatoid and epithelioid cells. Depending on the ratio of the two cell types, biphasic mesothelioma may grow or spread at varying rates. Diagnosing this type accurately often requires a surgical biopsy.