Diagnosis of mesothelioma includes history, physical exam, and histologic findings. Clinicians should have a high index of suspicion in any patient with a history of asbestos exposure 30 to 40 years prior to presentation. Exposure can occur in asbestos workers, family members of asbestos workers, and those living close to naturally occurring asbestos soil deposits. Common signs and symptoms at presentation include dyspnea, pleuritic or non-pleuritic chest pain, fatigue, weight loss, and pleural effusion. Asymptomatic patients may have pleural effusions that are found incidentally on physical exam or through radiographic studies. Thoracentesis decreases pleural effusions in 90 percent of patients, but cytologic studies of the pleural fluid are typically non-diagnostic. In suspected cases, thorascopically guided biopsy should be performed and is 98 percent diagnostic. A variety of immunohistochemistry stains should be performed to aid in diagnosis and to help distinguish mesothelioma from other lung neoplasms.
Plain radiographs may show pleural effusions which are the most common manifestation of mesothelioma. these radiographs may also show pleural thickening of the involved lung. Changes due to asbestosis or an actual mass may also be observed with plain radiographs. CT and MRI may further delineate the extent and involvement of mesothelioma. For instance, CT and MRI may determine the amount of lymph node involvement and/or chest wall invasion. However, these methods are often not able to differentiate between mesothelioma and other malignant or benign lung tumors such as adenocarcinoma. CT scans may be used for guidance in tumor biopsy performed by fine needle aspiration. PET scans are sometimes used to determine staging of mesothelioma. All sources seem to agree however, that final diagnosis of mesothelioma is most accurately achieved through thoracotomy and open biopsy.
Fatigue, dyspnea and hypoxia ensue. As the lesion invades thoracic structures, the following complications may develop.
A thorough medical history may reveal exposure to asbestos in the past or the presence of suspicious symptoms. Physical examination is followed by x-rays of the affected area of the body (lungs, heart, or abdomen). Positive x-rays signal the need for a CT scan (computerized tomography) or MRI (magnetic resonance imaging) for a detailed analysis of body structures. When the location of the abnormal cells is known, biopsies are taken. Biopsy of lung tissues is done by thoracotomy since the tumor affects the outer lung surface. Abdominal biopsies are obtained via laparoscopy. In both cases, small incisions allow the surgeon to visualize the internal organs and to take tissue for pathological examination.
Surgery is often needed to determine the staging of the disease. This reveals whether the tumor is self-contained or has spread to adjacent structures or other more remote areas of the body. This information can then guide treatment.
1. plueritic chest pain and dyspnea in 75% of patients is due to accumulation of pleural fluid.
2. Peritoneal involvement: abdominal pain and weight loss
3. Patient may be asymptomatic and disease is picked up incidentally on routine exam.
4. Presence of pleural or peritoneal fluid on X-ray
*Care should be taken when dealing with abdominal symptoms suggestive of peritoneal mesothelioma to always rule out a primary pulmonary source. Plueral mesothelioma is more common and very apt to metastasize to the peritoneal surface.
Likely the greatest challenge is the long latency period, from time of exposure to start of symptoms. Symptoms may develop anywhere from 20 to 50 years after exposure. Another challenge is the fact that even small or indirect exposures to asbestos can cause a mesothelioma and an individual may not report a history of exposure. An example of this may be a man that works around asbestos and his wife that shakes the dust off of his clothing before laundering. The wife may not report asbestos exposure. Further making the diagnosis difficult is the presenting symptoms are often much like the symptom of multiple other illnesses. For example, some symptoms of pleural mesothelioma may be shortness of breath, chest pain, coughing and hoarsness. These symptoms may also be present with bronchitis, myocardial infarction, laryngitis, pneumonia and a number of other common conditions.