A pleural biopsy should be considered in exudative effusions. It is not
indicated in transudative effusions. Even in exudative effusions, the role of a pleural
biopsy is being challenged.
I think we can place the role of a pleural biopsy in the correct perspective
after reviewing the diseases diagnosable by pleural biopsy. There is a long list of
diseases known to give exudative pleural effusions, only some of which are diagnosable by
pleural biopsy. Exudative effusions can be caused by malignancy, TB, SLE, rheumatoid
arthritis, pneumonia, pulmonary embolism, viral infections, asbestosis, myxedema, uremia,
drugs, idiopathic, etc.
A large majority of etiologies have no specific findings in the pleural biopsy.
They are diagnosed by circumstantial evidence by association and exclusion of malignancy
Malignancy is the most common etiology for exudative effusion and accounts for in excess
of 55% in all exudative effusions. A definitive diagnosis of malignancy can be made by
examination of the pleural tissue. Metastatic malignancy, mesothelioma, lymphoma and
leukemia fall into this category.
- Granulomatous Process:
For all practical purposes, tuberculous pleural effusion can be diagnosed only by the
pleural biopsy. Pleural fluid smears are rarely positive and the yield on fluid culture is
very low and time consuming. The combined diagnostic yield of histology and tissue culture
is close to 90%.
- Tuberculosis Effusion:
The incidence of tuberculous effusion is decreasing in affluent communities. In hospitals
that cater to the poor, the tuberculous effusion could account for 20-25% of exudative
effusions. In our institution, tuberculous accounts for 5% of exudative effusions.
In the appropriate clinical setting, the demonstration of non-caseating granuloma with
negative pleural tissue culture can be considered as acceptable evidence for the diagnosis
A H&E stain of the pleural tissue is non-diagnostic in lupus. However, the
immunofluorescent stain is diagnostic for lupus. Drug induced lupus has the same
The three main groups of disorders that can be diagnosed by a pleural biopsy are
- Malignancy (secondary, mesothelioma and lymphoma)
- Granulomatous (TB,
- Lupus (drug induced, denovo lupus)
I will present my modus operandi. The following lists criteria for selecting a
patient with pleural effusion for biopsy.
I see pleural effusion in three clinical settings:
- Part of anasarca:
In patients with anasarca, all we need to decide on is whether the
effusion is a transudate or an exudate and a biopsy is not indicated.
- Occurring with a disease known to cause pleural effusion:
In the clinical setting with a disease known to cause pleural effusion, our first task is
to consider tests which will confirm that disease (RA, pancreatitis, pneumonia, lupus,
another primary, etc). A pleural biopsy will be indicated only in patients with lupus and
when another malignancy exists.
- As a presenting problem:
When pleural effusion is the presenting problem, my initial procedure is a pleural biopsy.
The main working diagnosis is malignancy in this clinical setting. I favor a pleural
biopsy in this setting since 60% of diseases I have encountered are diagnosable by biopsy.
Most important, I do not want to miss the opportunity to diagnose a granulomatous
pleuritis secondary tuberculosis.
Are you aware that there is a controversy about the value of pleural biopsy?
With increased sophistication, pathologists are able to make a definitive diagnosis of
malignancy by pleural fluid cytology. The yield of three independent pleural fluid
cytology may be just as sensitive, without a pleural biopsy. Another concern is that
physicians are poorly trained in pleural biopsy and usually do not obtain adequate tissue.
I think there is a role for pleural biopsy. While the necessity of pleural
biopsy for the diagnosis of malignancy has decreased, certainly there is a need for the
biopsy in tuberculous effusions. I also think it is extremely valuable in confirming the
diagnosis of lupus. I have had extensive past experience with pleural biopsies and my
complication rate is negligible. I almost always obtain pleura.