There are three broad types of malignant mesothelioma also known as asbestos cancer: pleural mesothelioma, which affects the area around the lungs, peritoneal mesothelioma, which affects the area around the stomach and intestines, and pericardial mesothelioma, which affects the area around the heart. Each of the three types of malignant mesothelioma has its own set of symptoms. In addition, there are (rare) benign mesotheliomas, and even rarer, a form of malignant mesothelioma that affects the genital region in men.

Pleural mesothelioma often presents as being very similar to viral pneumonia, and the symptoms are further complicated by the fact that patients with pleural mesothelioma often also have an additional lung infection, pneumonia, or bronchitis. Common symptoms of pleural mesothelioma include shortness of breath, chest pain, and chronic cough. Less commonly, patients report fever, night sweats, unexplained weight loss, and swollen lymph nodes. In rare cases, patients report coughing up blood, hoarseness, or difficulty swallowing. Not all patients develop all symptoms or in the same order, making diagnosis more complicated. For example, about sixty percent of patients develop shortness of breath, around seventy percent have chest pain, and thirty percent have both.

Peritoneal mesothelioma symptoms include pain and swelling of the abdomen, weight loss, nausea, development of abdominal masses, bowel obstruction (caused by the tumor pressing in on the intestines), changes in bowel habits including constipation or diarrhea, swelling of the extremities, more frequent urination, and anemia. The most common symptoms are abdominal pain (reported by sixty-three percent of patients) and abdominal swelling (seventy percent). Forty percent of patients report development of an abdominal mass. One fairly common combination of symptoms is a decrease in weight accompanied by an increase in the size of the patient’s weight; this seeming contradiction is caused by the burning of fat stores by the body (since digestion is not working well and the patient is not getting sufficient nutrition from food) while at the same time the abdomen is filling with fluid from the tumor, a condition also known as ascites.

Pericardial mesothelioma has a less clear-cut symptom profile, and is even more easily confused with other conditions than is pleural mesothelioma. Most pericardial symptoms derive from the filling of the pericardium with fluid from the tumor, putting pressure on the heart with a number of possible side effects. Patients report heart palpitations and difficulty in breathing, along with an increased heart rate or an abnormal pulse. This is caused by the fluid in the pericardium making it more difficult for the heart to fill with blood, meaning that it has to pump harder to distribute the oxygen-laden blood to the body. This may also explain the feeling of shortness of breath, despite the lack of actual compression on the lungs.

Benign mesothelioma, which is a non-malignant tumor that forms without any connection to asbestos, presents symptoms including shortness of breath, chest pain, coughing, and clubbed fingers. Mesothelioma of the tunica vaginalis (the mesothelial outgrowth that covers the scrotum) can cause small tumors to form on the testes and the development of a fluid-filled sac on the scrotum which causes it to swell. These conditions are very rare, however.