19
Pleural, Peritoneal, and Pericardial Effusions
Wahl's cases and some of ours, we suggest that mucosubstances
normally present in submesothelial tissue account for spiral for-
mation, especially if there is an overlay of inflammation.165 Such
inflammation may increase mesothelial permeability, thereby
facilitating transport of mucosubstances into a serosal cavity.
Whatever the mode of formation of Curschmann spirals is, they
are a rarity of no known clinical significance.
Key features of Curschmann spirals:
• A rare finding; spirals usually small; and
• More prevalent in mucin-containing effusions.
charcot-Leyden crystals
Charcot-Leyden crystals were first described in a serous effusion
(peritoneal) in 1899; however, from the scarcity of reported
examples subsequently it appears to be a rarely observed phe-
nomenon. In all of the spontaneously occurring examples of
Charcot-Leyden crystals in serous effusions in which a descrip-
tion of the accompanying cells was provided, it is obvious that
the fluids were classifiable as eosinophilic.6,8,167,168 This is under-
standable because the extensive literature on eosinophilic leu-
kocytes clearly indicates that Charcot-Leyden crystals develop
from degenerating eosinophilic leukocytes.31 That the crystals
are so rarely seen in serous fluids is a result of processing the
fluids while they are fresh and relatively warm, before crystals
have time to form from the cytoplasmic granules released from
degenerating eosinophils.
In all our cases, the crystals were observed only in the toluid-
ine blue-stained wet films, never in the permanent smears or cell
blocks. Either the wet films or the specimens of fluid from which
they had been prepared had stood in the refrigerator at 4°C for
at least 24 hours. The crystals were typical Charcot-Leyden crys-
tals: slender birefringent needles of uniform shape but of vari-
able length and width, consisting of two hexagonal pyramids
joined base to base (see Fig. 19.11). Eosinophil leukocytes were
readily found in these wet films. Some crystals were free in the
fluid medium, some were alongside eosinophilic leukocytes, and
some seemed to be emerging from eosinophilic leukocytes.
The most likely situation in which Charcot-Leyden crystals
can be found in a serous fluid is in a stained wet film prepared
from an eosinophilic effusion that has been stored in a refrig-
erator, particularly during a weekend when a laboratory may be
closed. We have observed Charcot-Leyden crystal formation in
serous effusions only in such circumstances. Except for this crys-
tal formation being an expression of at least a local eosinophilia,
which may have resulted from a wide variety of stimuli, it is not
of any known significance. It is merely an interesting curiosity.
Key features of Charcot-Leyden crystals
• Slender birefringent crystals consisting of two
hexagonal pyramids joined base to base;
• Produced from cytoplasmic granules of disintegrated
eosinophil leukocytes; and
• Found only in wet films of eosinophilic effusions that
have been stored cold.
Ferruginous (Asbestos) Bodies
The literature records two examples of what appear to be typi-
cal asbestos bodies in pleural effusion; one of the patients
was described as having a history of asbestos exposure.20,117
It is possible that asbestos bodies could enter the pleural cavity
through a bronchopleural fistula, although in neither of these
cases was the presence of such a fistula mentioned. Without such
a history, it is presumed that the thoracentesis needle penetrated
the pulmonary parenchyma.
The rare finding of such bodies in a pleural effusion should
be regarded as significant of a heavy asbestos burden in the lung.
It is well recognized that virtually all inhabitants of modern
urban societies have ferruginous bodies in their lungs, but the
concentration of ferruginous bodies in members of the general
population is so low that they are seldom found in routinely
prepared sections of lung. Therefore, without a clear history of
bronchopleural fistula, the finding of even one ferruginous body
in a pleural effusion should indicate not only that the thoracen-
tesis needle penetrated the pulmonary parenchyma but also that
the asbestos burden in the lung is heavy.
Key features of ferruginous (asbestos) bodies
• Extremely rare in effusions; and
• Denotes a fistula between lung and pleural cavity or
aspiration needle penetrated pulmonary parenchyma.
Reaction to ionizing Radiation and chemotherapy
It has long been our impression that mesothelial cells in
serous fluids, unlike epithelial cells from various organs, show
little or no detectable reaction to ionizing radiotherapy or to
chemotherapy, and that if they do show a reaction it is not rec-
ognizable as such. Until recently, only anecdotal accounts of
radiation reaction of mesothelial cells in peritoneal and pleural
fluids existed.20,32,78 The matter was approached systematically
by Wojno and colleagues, who analyzed 24 morphologic fea-
tures of mesothelial cells in pleural effusions in patients who
had undergone ionizing radiotherapy and contrasted them
with those of mesothelial cells in pleural effusions from non-
irradiated patients.169 They concluded that none of the features
was found more frequently in the irradiated specimens. Their
results support our impression that ionizing radiation therapy
does not consistently produce distinctive cytologic changes in
pleural effusions and that a history of ionizing radiation therapy
should not affect the interpretation of these specimens. We are
not aware of any consistent and distinctive changes in mesothe-
lial cells in effusions brought about by chemotherapy.
Key features of reaction to ionizing radiation and
chemotherapy
• No consistent and distinctive changes in mesothelial
cells.
Neoplastic Effusions
General
Many effusions associated with cancer are a result of some form
of indirect mechanism, such as a transudate that develops as a
result of venous obstruction caused by neoplasm or an exudate
that develops as a result of inflammatory changes in an organ
secondary to the presence of neoplasm. These are extremely
common situations, and in such effusions neoplastic cells are
not expected to be found. Even when a serous fluid contains
neoplastic cells, the number of such cells may vary considerably,
from a specimen that consists of almost 100% neoplastic cells to
549
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