A relatively easy case. The chest radiograph demonstrates appearances of pneumomediastinum and surgical emphysema extending into the neck. The lung parenchyma is hyperinflated. At first inspection the lung parenchyma also demonstrates reticular markings, however, more careful inspection suggest these are actually diffuse cystic findings. The extent of cystic abnormalities discounts the possibility that these reflect bronchiectatic airways. It is notable that there is relative sparing of the lung bases. These findings are highly suggestive of the diagnosis.
The HRCT imaging at a later date is confirmatory. This demonstrates the extensive cystic distribution disease in the upper lobes, with relative sparing of the lung bases. Notably many of the cysts have a "bizarre" shape. Overall these appearances are highly suggestive of Langerhan's Cell Histiocytosis (Histiocytosis X). The appearances in this case are so suggestive on CXR that the HRCT is nearly superfluous! This disease appears almost exclusively in male smokers. Early forms of the disease may be associated with ill-defined nodules, these may progress to cavitary small nodules and eventually pure cystic disease. Early forms of disease can significantly improve or completely regress following cessation of smoking. Later forms of the disease can be more confusing as the cystic element may be less apparent and the confluent disease starts to resemble extensive reticular upper lobe fibrosis even on HRCT.
The differential diagnosis for cystic lung disease is relatively limited. This can be considered in association with the size and distribution of cysts as well as the presence of nodules or ground glass:
Differential:
Cysts alone:
Polycystic:
1. Langerhans
2. Lymphangioleiomyomatosis - no zonal predeliction, smaller uniform cysts, may see pneumothorax or rarely chylothorax, accessory features of tuberous sclerosis if co-present
Oligocystic:
1. Lymphocytic Interstitial Pnemonitis (usually larger cysts at lung bases)
2. Remote post infective pneumatoceles
3. Birt-Hogg-Dube (rare - in association with renal tumours)
Cysts and Nodules:
Polycystic:
Langerhans (early)
Oligocystic
Lymphocytic Interstitial Pnemonitis (small peri-cystic nodules may be present, if larger and more prominent consider the coexistance of LIP and amyloid)
Cysts and Ground Glass:
PCP infection
The HRCT imaging at a later date is confirmatory. This demonstrates the extensive cystic distribution disease in the upper lobes, with relative sparing of the lung bases. Notably many of the cysts have a "bizarre" shape. Overall these appearances are highly suggestive of Langerhan's Cell Histiocytosis (Histiocytosis X). The appearances in this case are so suggestive on CXR that the HRCT is nearly superfluous! This disease appears almost exclusively in male smokers. Early forms of the disease may be associated with ill-defined nodules, these may progress to cavitary small nodules and eventually pure cystic disease. Early forms of disease can significantly improve or completely regress following cessation of smoking. Later forms of the disease can be more confusing as the cystic element may be less apparent and the confluent disease starts to resemble extensive reticular upper lobe fibrosis even on HRCT.
The differential diagnosis for cystic lung disease is relatively limited. This can be considered in association with the size and distribution of cysts as well as the presence of nodules or ground glass:
Differential:
Cysts alone:
Polycystic:
1. Langerhans
2. Lymphangioleiomyomatosis - no zonal predeliction, smaller uniform cysts, may see pneumothorax or rarely chylothorax, accessory features of tuberous sclerosis if co-present
Oligocystic:
1. Lymphocytic Interstitial Pnemonitis (usually larger cysts at lung bases)
2. Remote post infective pneumatoceles
3. Birt-Hogg-Dube (rare - in association with renal tumours)
Cysts and Nodules:
Polycystic:
Langerhans (early)
Oligocystic
Lymphocytic Interstitial Pnemonitis (small peri-cystic nodules may be present, if larger and more prominent consider the coexistance of LIP and amyloid)
Cysts and Ground Glass:
PCP infection
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