·
Sharply marginated
collection of pleural fluid contained
either within an interlobar pulmonary
fissure or in a subpleural location
adjacent to a fissure
·
Result from transudation
from the pulmonary vascular space
·
Commonly manifest as
incidental radiographic findings in
patients with congestive heart failure
o
Other causes of
transudates include
§
Hypoalbuminemia
§
Renal insufficiency
·
Imaging findings
o
Lenticular or biconvex
contour
o
Located along the course
of interlobar fissures
§
Most occur in the minor
(horizontal) fissure (more than 75%) and
are seen on both the frontal and lateral
radiograph
§
Those that occur in the
oblique or major fissure may only be
seen on the lateral view well
§
Infrequently, they occur
in the horizontal and oblique fissures
simultaneously
o
Most are less than 4 cm in
size
Frontal and lateral views of an 89
year-old female with an oval soft tissue
density superimposed on the minor fissure
on both the frontal and lateral views. The
lesion has slight "points" where it abuts
the minor fissure, a sign of a
"pseudotumor" or "vanishing tumor" in the
minor fissure. There are usually more
signs associated with congestive heart
failure than are seen in this patient.
For a larger version of this photo,
click here
·
Management
o
The underlying condition is
managed
o
Typically an incidental
finding that has minimal impact on patient
management
·
Patients who develop
pseudotumors tend to develop time
repeatedly when the underlying condition
causing the transudate (like CHF) returns
·
Pseudotumors may be
erroneously diagnosed as parenchymal lung
nodules or masses
·
Presence of an interlobar
pleural effusion does not always
correspond to the severity of the left
heart failure
o
Occasionally, it may be the
only sign of cardiac decompensation
