Diffuse malignant pleural mesothelioma is known as one of the most malignant tumors with a yearly incidence in the United States reaching a figure of 2,000 to 3,000 cases. Its inherent natural history is mainly typified by local aggressiveness along with invasion, which, when left untreated, may lead in a median survival ranging between four and twelve months. Even though the exposure to asbestos still remains the most essential epidemiological factor in the spread and development of this particular disease, the significance of the simian virus 40, also known as SV40, has been lately recognized. The management of diffuse malignant pleural mesothelioma poses a number of hurdles to physicians, ranging from diagnosis and staging to extensive treatment. The dearth of randomized researches and the low incidence of the very tumor are the main reason why there has yet to be any consensus regarding how the tumor should be treated.
Medical Evidence
Mesothelioma most commonly occurs in males, as evinced by a ratio of 3:1 males to males. The disease is unilateral in the majority of patients (95%) with a sheer right-sided preponderance, and it develops as a corollary of the exposure to asbestos subsequent to a median latency period of thirty two years. Even though most patients are over the age 55 when the presentation is carried out, cases have been unearthed to occur in younger patients, which include children. Such cases occur because of causes other than the exposure to asbestos. The majority of patients are found to suffer from symptoms pertinent to pleural effusion, such as chest pain, dyspnea, and cough. Some other symptoms such as weight loss, fatigue, night sweats, and fever are also likely to occur.
At first, dyspnea develops due to the result of pleural effusion, yet as the tumor gets bigger, it substitutes the pleural space, and the lung gets entrapped. In similar case, the chest pain which occurs due to the presence of pleural effusion is initially poorly localized as well as dull. Just as the tumor develops, however, some intercosctal nerves get entrapped, and the pain will become localized. Unrelenting tumor development leads to mediastinal and abdominal invasion. Ascites, abdominal wall deformity, cachexia, cardio pulmonary compromise, and bowel obstruction result in the patient’s demise. Metastases in the bone, brain, and some other organs hardly occur. However, such metastases have been more frequently present in patients that have been given multimodality therapy. On physical checkup, most patients with mesothelioma, especially with early disease, only manifest only the signs of pleural effusion, which may comprise of decreased breaths sounds. With the more advanced disease, abdominal masses or palpable chest can be present. Abdominal masses are especially ominous signs since they convincingly manifest transdiaphargmatic involvement and unresectability.
Laboratory tests are not quite useful in shedding lights on this tumor, even though thrombocytosi s (> 400 × 10 /L) is known as an indicator of poor prognosis. On the other hand, laboratory evaluation can lend itself to unraveling other nonspecific findings such as eosinophilia, anemia of chronic diseases, and even hypergammaglobulinemia.
Radiologic Experiment
Standard evaluation based on radiologic work-up of mesothelioma patients have to include a magnetic resonance imaging (MRI), computed tomography (CT), and a chest x-ray. Pleural effusions, thickening, and plaques can be examined on plain chest x-rays. However, the resectability is best decided with MRI and CT scans, which can better evaluate the extent of invasion towards the chest wall, diaphragm, and mediastinum. Surgeons have disputed whether CT or MRI scan offers more information and higher precision in deciding on the resectability; we actually have found MRI to be more helpful and gaining broader information, yet the operation of both tests at the same time is quite effective in deciding on the resectability.
Fluorodeoxyglucose positron-emission tomography (PET) has been operated with increasing frequency at our clinic, chiefly to evaluate distant occult disease. The increased sensitivity of this very modality was reported in a recent research of 18 consecutive patients with diffuse malignant pleural mesothelioma. The PET scan has detected the presence of distant disease in 2 patients in spite of negative CT scans and was found to be more sensitive than CT in evaluating mediastinaladenopathy. Another investigation which is related to survival rate with intensity of uptake on scan deploying PET, which soundly indicates an ability to quantify tumor burden.
Bi-dimensional echocardiography can be another helpful alternative test with which to find out resectablity. This particular technique refers to the assessment of pericardical involvement and cardiac function.
A Pathological Diagnosis
Diagnostic aids to differ malignant pleural mesothelioma from adenocarcinoma. When a patients present with unilateral pleural effusion, physician needs to relieve the occurring symptoms by draining liquid and then establish the trigger of the effusion. The three most widely applied methods for attaining these objectives are thoracentesis with cytology, open pleural biopsy through vide-assisted thoracic surgery, and closed pleural biopsy.
Thoracentesis is commonly applied in the first evaluation and management of these effusions. They are mostly effectively drained, and the liquid can be delivered for cytologic and chemical evaluation. Mesothelioma-related effusions are particularly transparent clear yellow. However, Thoracentesis lends itself to establishing a diagnosis in merely 30% to 35% of cases because of its inability to differ tumor cells from reactive mesothial cells.
This weak diagnostic result has been enhanced with the aid of histochmistry, electron microscopy, and immunohistochemistry. Closed pleural needle biopsy can be operated in order to gain pleural tissue and enhance the diagnostic outcome. For the most part, however, this denotes a blind strategy with a high incorrect negative rate since the malignant mass may be missed and, instead, normal plura biopsied. Vide-aided thoracic surgery is not quite invasive technique which improves the visualization, effectively drains all fluid by disrupting any loculations, and then further provides a sufficient number of tumor tissue samples for varied stains and also electron microscopy. In other words, these findings have shed lights on the need to embark on prototyping innovative therapies, which are essential to prolong survival rates in patients with both early and advanced disease.
