- • Associated with asbestos exposure.
- • Nonexertional chest pain and dyspnea are presenting
- • Pleural effusion is common.
- • Pleural thickening and/or nodules are
present on chest computed tomography (CT).
- • Thoracoscopy or thoracotomy is often required for
Malignant pleural mesothelioma (MPM) is a rare tumor with only
2000–3000 new cases each year in the United States. MPM
is strongly associated with asbestos exposure, which can be documented
in up to 80% of cases. Thus, workers with heavy industrial
exposure to asbestos, such as pipe fitters, naval yard workers,
plumbers, welders, and asbestos factory workers, have a remarkably
higher risk of developing MPM than the general population. Asbestos
fibers are found more frequently and in larger concentrations in
the lung parenchyma of patients with MPM than in the general population.
Animal studies also corroborate a role of asbestos in the pathogenesis
Recent interest has focused on a potential role of simian virus
40 (SV40) in the etiology of this malignancy. Several lines of preclinical
research support this hypothesis such as the presence of SV40 sequences
in MPM tumors. It has been suggested that SV40 may interact with
asbestos fibers to induce MPM. This issue is controversial, but
provides a basis for investigational approaches to management of
MPM such as vaccine therapy against the SV40 tumor antigen.
MPM is generally a disease of advanced age. The median age is
approximately 60, consistent with prolonged latency between asbestos
exposure and clinical manifestation of disease, which is typically
two to five decades. The male:female ratio is 4–5:1.
There are three main pathological subtypes: epithelial, sarcomatoid,
and mixed histology. The sarcomatoid variant is relatively uncommon
and has the worst prognosis. The epithelial subtype is associated
with better survival.
As described below, management of MPM has largely been characterized
by pessimism, but recent developments have provided an increasing
number of treatment options.
Nonexertional, nonpleuritic chest pain and/or dyspnea
are the presenting symptoms in 90% of patients. These symptoms
typically wax and wane but do not resolve. Over time MPM encases the
lung and progressively invades the chest wall, leading to worsening
dyspnea and constant pain. Other symptoms include cough, weight
loss, and fever. Spontaneous pneumothorax is occasionally the presenting
symptom of the disease.
Physical examination typically demonstrates decreased breath
sounds and associated dullness to percussion in areas of marked
pleural thickening and/or pleural effusion. A chest wall
mass may be evident late in the course of the disease.
There are no specific laboratory findings that are diagnostic
for MPM, but mild thrombocytosis and anemia are common.
Chest radiographs reveal a pleural effusion ...