CT appearance of Pulmonary Langerhans Cell Histiocytosis (LCH) and approach to imaging of cystic lung diseases
Pulmonary LCH is a rare disease found almost exclusively in cigarette smokers.
Radiologic findings of pulmonary LCH include
- Nodules, usually smaller than 1 to 5 mm, centrilobular, and peribronchiolar, may be cavitary, may be seen in association with cysts.
- Thick-walled or thin-walled cysts. – Progression over time from nodules to thick-walled cysts to thin-walled cysts.
- Upper lobe predominance in size and number of nodules or cysts, costophrenic angles spared.
- It can be associated with lymphadenopathy.
Pulmonary LCH vs lymphangioleiomyomatosis radiology
|Imaging features of Pulmonary Langerhans Cell Histiocytosis||Imaging features of Lymphangioleiomyomatosis|
|– Thick-walled, or thin-walled cysts|
– Nodules, usually smaller than 1 to 5 mm, centrilobular and peribronchiolar, may be cavitary, may be seen in association with cysts
– Progression over time from nodules to thick-walled cysts to thin-walled cysts
– Upper lobe predominance in size and number of nodules or cysts, costophrenic angles spared
– Fine reticular opacities
– Ground-glass opacity
– Mosaic perfusion or air trapping
– Pulmonary hypertension
|– Thin-walled lung cysts, usually round in shape|
– Diffuse distribution, costophrenic angles involved
– Mild septal thickening or ground-glass opacity
– Lymph node enlargement
– Small nodules in patients with TSC
– Pleural effusion
Common causes of cystic lung disease
Common (not truly cystic lung diseases but often confused as cysts)
- Emphysema (e.g., bullae) – Thin imperceptible walls.
- Cystic bronchiectasis
- Pulmonary Langerhans Cell Histiocytosis
- Lymphangioleiomyomatosis (isolated LAM or associated with the TSC)
- Lymphocytic interstitial pneumonia (LIP) – Associated with Sjogren’s, AIDS, SLE
- Cystic metastases
- Pneumatoceles –
- Birt-Hogg-Dube syndrome = Lung cysts and renal oncocytomas.
Approach to imaging of cystic lung diseases
Watch the video for the detailed case discussion and PACS based image stack.
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