Etymology
Derived from the Greek prefix “pseudo,” meaning false, and “cavity,” indicating a hollow space.
AKA
False cavity
Definition
What is it?
A pseudocavity refers to an imaging finding that resembles a true cavity but does not represent a gas-filled hollow space. Instead, it is often a solid or fluid-filled structure or an area of focal attenuation or consolidation within the lung.
Caused by
Inflammatory or Infectious Conditions
Cryptogenic Organizing Pneumonia (COP), where pseudocavities are formed by perilobular opacities or collapsed lung tissue.
Non-specific Interstitial Pneumonia (NSIP), with linear and ground-glass changes mimicking cavities.
Neoplastic Processes
Adenocarcinoma, particularly the lepidic subtype, which can present with pseudocavities within ground-glass opacities.
Mechanical Causes
Alveolar collapse or consolidation with trapped air mimicking a hollow space.
Resulting in
Misinterpretation as a true cavity on imaging, potentially leading to diagnostic confusion.
Structural changes
Pseudocavities typically lack wall thickening or communication with airways seen in true cavities and are often surrounded by ground-glass opacities or consolidation.
Pathophysiology
In infectious or inflammatory conditions
Pseudocavities arise due to alveolar collapse, partial liquefaction, or replacement by inflammatory tissue.
In neoplastic conditions
Represent intraparenchymal tumor changes, such as necrosis or mucin production.
Pathology
Histologically, pseudocavities correspond to areas of alveolar filling or partial destruction, with no evidence of an actual air-filled space.
Diagnosis
Clinical
Symptoms depend on the underlying cause, such as cough and dyspnea in inflammatory conditions or systemic symptoms in malignancies.
Radiology
Differentiating pseudocavities from true cavities relies on careful evaluation of imaging features, including wall characteristics, surrounding opacities, and lack of an air-fluid level.
Labs
May include infectious workups, autoimmune markers, or tumor markers as appropriate for the suspected etiology.
Treatment
Management depends on the underlying cause, ranging from corticosteroids for inflammatory diseases to targeted therapies for neoplasms.
Radiology
CXR
Findings
Small, round, or oval lucencies, often seen within areas of consolidation or ground-glass opacity.
Associated Findings
Surrounding inflammatory or neoplastic changes.
CT
Parts
Includes the pseudocavity itself, surrounding parenchymal changes, and potential associated abnormalities.
Size
Typically smaller than true cavities, ranging from a few millimeters to a centimeter.
Shape
Round, oval, or irregular, often with indistinct margins.
Position
Commonly seen in subpleural or perilobular regions, especially in COP or adenocarcinoma.
Character
Lack of thick walls, absence of air-fluid levels, and association with surrounding consolidation or ground-glass opacities.
Time
May evolve with treatment or disease progression.
Associated Findings
Ground-glass opacity, consolidation, or fibrotic changes.
Other relevant Imaging Modalities
MRI/PET-CT/NM/US/Angio
PET-CT can help differentiate metabolically active pseudocavities from benign or inflammatory changes.
Pulmonary function tests (PFTs)
PFTs are generally non-specific but may show restrictive patterns in associated interstitial lung diseases.
Recommendations
Thorough radiologic evaluation is essential to distinguish pseudocavities from true cavities.
Biopsy or further imaging may be needed for definitive diagnosis in cases of diagnostic uncertainty.
Key Points and Pearls
Pseudocavities are commonly seen in Cryptogenic Organizing Pneumonia (COP) and lepidic adenocarcinoma.
Differentiation from true cavities is critical, as the management and prognosis differ significantly.
Lack of a surrounding thick wall or air-fluid level is a key distinguishing feature.
Serial imaging may help assess evolution and guide management.
