Why Diagnosing Mesothelioma Can Be Tricky

Nearly always caused by exposure to asbestos materials (even small amounts), mesothelioma is a rare form of cancer that affects the membrane that covers most of our body’s organs, including the abdomen, heart and lungs.

This guide will explain why diagnosing mesothelioma can be tricky, and the various tests involved to confirm whether a person has it.

Difficulty in Pin-Pointing Mesothelioma

The reason that a number of tests may be required to reach a diagnosis of mesothelioma is that there are many different types of cells that can be present in a mesothelioma tumour and they tend to look similar to other types of cancer cells. This makes it very difficult for a pathologist (doctor who specialises in identifying cells under a microscope) to decide if the cells taken from the lungs or the abdomen are indeed mesothelioma rather than a different type of cancer.

Additionally, the usual tests that doctors employ to diagnose lung disease often read negative when trying to pin-point mesothelioma.
Because of this, you might need to undergo a number of tests so that your doctor can be certain you have mesothelioma.

Mesothelioma Tests

The first step in diagnosing mesothelioma is visiting your GP, who will ask you questions about your symptoms, feel for pain and swelling as well as listen to your chest for signs of fluid. You will then be referred either to a specialist or to a hospital for tests. First they will order routine blood tests, then you will be scheduled in for some of the following:

X-ray & Ultrasound

The main areas that mesothelioma affects are the chest (causing fluid collection) and abdomen (causing fluid and/or swelling), so one of the first tests will be to have an X-ray of these areas. Alternatively, you could be booked in for an ultrasound scan which would reveal any abdomen abnormalities.

CT Scan

A CT (computerised) scan uses X-rays to show abnormal swellings in body organs or lymph nodes. You may be given an injection of dye to make the scan clearer to read.

If the scan uncovers any abnormalities, your doctor might suggest a CT guided biopsy, which involves taking a small sample of tissue by inserting a fine needle through the skin and into the tumour. You will not feel pain as the procedure is done with local anaesthetic to numb the area.

Fluid Drainage

A common symptom of pleural (chest) mesothelioma is a fluid build-up around the lungs, and you can also have it in the abdominal cavity (called a peritoneal effusion). This occurs because cancer cells cause these areas to become inflamed, making it difficult to breathe or the abdomen to feel uncomfortably tight and swollen.

Since the fluid may contain cancer cells, doctors drain a sample of it by inserting a needle attached to a tube and small bag. If fluid is drained from your chest it is called thoracocentesis or pleural aspiration, whereas if it is drained from the abdomen it is called abdoparacentesis or peritoneal aspiration. The sample will then be sent to a lab to test for cancer cells.

Thoracoscopy (Pleural/Lung Biopsy)

If the doctor suspects you have mesothelioma in the lungs, you could be scheduled in for a thoracoscopy, which is a minor operation to take a small sample (biopsy) of the tissues which cover the lungs (pleura). This can be done with the patient under a general anaesthetic, a local anaesthetic or sedation. A small incision is made in your chest wall through which the surgeon inserts a thoracoscope (a flexible tube with a light and video camera attached).

A CT scan or ultrasound scan might be used to ensure they position the needle accurately. Once they hone into the right area, they will use forceps to extract a sample from the outer layer of the pleura (parietal layer) so that it can be sent to a lab to test for cancer cells. This is sometimes the only sure way of finding out whether you have mesothelioma in your lungs as opposed to a different problem or form of cancer.

Laparoscopy (Peritoneal/Abdominal Biopsy)

If the doctor suspects you have mesothelioma in your abdomen, you could be scheduled in for a laparoscopy. In similar way to a thoracoscopy, the surgeon will make an incision in your abdomen to insert a small tube attached to a camera and light so they can see if there are any abnormal areas (for this reason sometimes the camera is inserted through more than one cut). They will take a sample of abnormalities to send to a lab for testing.

Surgical/Open Biopsy

As a last resort if all other tests for mesothelioma have proven inconclusive, you will be scheduled in for an open biopsy so that a surgeon can investigate fully. You will not be awake for this, it will be performed under general anaesthetic.


Once you have undergone the necessary tests, you will need to wait for the results to come in, which might take anything from a few days to a few weeks. This can be rather nerve wracking, so it’s advisable to ease your tension by chatting about it with a friend or family member. Alternatively, there are cancer support groups where you can talk to other people who have been through the same thing. If your diagnosis of mesothelioma is confirmed however, you will have a guaranteed case for compensation.