Lymphocytic interstitial pneumonitis
Lymphocytic interstitial pneumonitis is a benign lymphoproliferative disorder characterized by lymphocyte predominant infiltration of the lungs. It is classified as a subtype of interstitial lung disease. It also falls under the umbrella of non-lymphomatous pulmonary lymphoid disorders.
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Epidemiology
Lymphocytic interstitial pneumonitis can occur at any age. However, most of the patients are adults with a mean age of 50 years. If a child presents with lymphocytic interstitial pneumonitis, this can be indicative of AIDS.
There is a recognized female predilection most likely attributable to the fact that lymphocytic interstitial pneumonitis occurs in patients with autoimmune disease such as Sjögren syndrome, which is by far more common in women 8.
Clinical presentation
The main clinical symptoms are a gradual onset of dyspnea and cough with approximately six months duration. Less frequently, patients may have systemic symptoms such as fever, night sweat, arthralgia, and weight loss. If the disease progresses to the end-stage respiratory failure cyanosis and clubbing may develop. Hypertrophy of the salivary glands observed in 20% of patients 11.
Pathology
There is diffuse infiltration of the interstitium and alveolar spaces by lymphocytes and plasma cells.
Associations
- Sjögren syndrome: can occur in up to 25% of those with lymphocytic interstitial pneumonitis 6
- AIDS: particularly if it occurs in the young 9
- autoimmune thyroid disease
- systemic lupus erythematosus
- Castleman disease
- common variable immune deficiency 10
- rheumatoid arthritis
- pulmonary amyloidosis
Markers
In about 80% of patients polyclonal or IgM monoclonal gammopathy is found 8.
Radiographic features
Plain radiograph
Features can be non-specific, but may include:
- lower-zone predominant bilateral reticular opacification
- chronic bilateral airspace opacification
CT
The following features may be seen with lymphocytic interstitial pneumonitis on HRCT, but the findings are not exclusive to its diagnosis:
- features tend to be diffuse with mid to lower lobe predominance
- thickening of bronchovascular bundles
- interstitial thickening along lymph channels 2
- small but variable sized pulmonary nodules (can be centrilobular or subpleural, and are often ill-defined)
- ground-glass changes
- scattered thin-walled cysts
- usually deep within the lung parenchyma
- typically abut vessels (i.e. is perivascular or subpleural)
- size range between 1-30 mm (useful for differentiation from lymphoma of the lung 1)
- mediastinal lymphadenopathy
Treatment and prognosis
The natural history is variable, from near-complete resolution to progressive disease. More than 30% of patients will develop the end-stage disease and honeycombing despite treatment.
Transformation to lymphoma can occur, particularly in a patient with monoclonal gammopathy or hypogammaglobulinemia 8. Corticosteroids have been successfully trialled 1.
Differential diagnosis
General imaging differential considerations include:
-
pneumocystis pneumonia (PCP)
- cystic changes (pneumatoceles) seen in advanced disease
- can be difficult to differentiate particularly in those with AIDS
-
lymphangioleiomyomatosis
- occur in younger females
- cysts are generally uniformly distributed throughout the lungs
-
Langerhans cell histiocytosis
- smokers
- bizarre cysts that spare the costophrenic angles
- upper lung zone predominant
See also
Related Radiopaedia articles
Chest
- imaging techniques
-
chest x-ray
-
approach
- adult
- pediatric
- neonatal
-
airspace opacification
- differential diagnoses of airspace opacification
- lobar consolidation
-
atelectasis
- mechanism-based
- morphology-based
- lobar lung collapse
- chest x-ray in the exam setting
- cardiomediastinal contour
- chest radiograph zones
- tracheal air column
- fissures
- normal chest x-ray appearance of the diaphragm
- nipple shadow
-
lines and stripes
- anterior junction line
- posterior junction line
- right paratracheal stripe
- left paratracheal stripe
- posterior tracheal stripe/tracheo-esophageal stripe
- posterior wall of bronchus intermedius
- right paraspinal line
- left paraspinal line
- aortic-pulmonary stripe
- aortopulmonary window
- azygo-esophageal recess
- spaces
- signs
- air bronchogram
- big rib sign
- Chang sign
- Chen sign
- coin lesion
- continuous diaphragm sign
- dense hilum sign
- double contour sign
- egg-on-a-string sign
- extrapleural sign
- finger in glove sign
- flat waist sign
- Fleischner sign
- ginkgo leaf sign
- Golden S sign
- Hampton hump
- haystack sign
- hilum convergence sign
- hilum overlay sign
- Hoffman-Rigler sign
- holly leaf sign
- incomplete border sign
- juxtaphrenic peak sign
- Kirklin sign
- medial stripe sign
- melting ice cube sign
- more black sign
- Naclerio V sign
- Palla sign
- pericardial fat tag sign
- Shmoo sign
- silhouette sign
- snowman sign
- spinnaker sign
- steeple sign
- straight left heart border sign
- third mogul sign
- tram-track sign
- walking man sign
- water bottle sign
- wave sign
- Westermark sign
-
approach
- HRCT
-
chest x-ray
- airways
- bronchitis
- small airways disease
-
bronchiectasis
- broncho-arterial ratio
- related conditions
- differentials by distribution
- narrowing
-
tracheal stenosis
- diffuse tracheal narrowing (differential)
-
bronchial stenosis
- diffuse airway narrowing (differential)
-
tracheal stenosis
- diverticula
- pulmonary edema
-
interstitial lung disease (ILD)
- drug-induced interstitial lung disease
-
hypersensitivity pneumonitis
- acute hypersensitivity pneumonitis
- subacute hypersensitivity pneumonitis
- chronic hypersensitivity pneumonitis
- etiology
- bird fancier's lung: pigeon fancier's lung
- farmer's lung
- cheese workers' lung
- bagassosis
- mushroom worker’s lung
- malt worker’s lung
- maple bark disease
- hot tub lung
- wine maker’s lung
- woodsman’s disease
- thatched roof lung
- tobacco grower’s lung
- potato riddler’s lung
- summer-type pneumonitis
- dry rot lung
- machine operator’s lung
- humidifier lung
- shower curtain disease
- furrier’s lung
- miller’s lung
- lycoperdonosis
- saxophone lung
-
idiopathic interstitial pneumonia (mnemonic)
- acute interstitial pneumonia (AIP)
- cryptogenic organizing pneumonia (COP)
- desquamative interstitial pneumonia (DIP)
- non-specific interstitial pneumonia (NSIP)
- idiopathic pleuroparenchymal fibroelastosis
- lymphoid interstitial pneumonia (LIP)
- respiratory bronchiolitis–associated interstitial lung disease (RB-ILD)
- usual interstitial pneumonia / idiopathic pulmonary fibrosis (UIP/IPF)
-
pneumoconioses
- fibrotic
- non-fibrotic
-
lung cancer
-
non-small-cell lung cancer
-
adenocarcinoma
- pre-invasive tumors
- minimally invasive tumors
- invasive tumors
- variants of invasive carcinoma
- described imaging features
- adenosquamous carcinoma
- large cell carcinoma
- primary sarcomatoid carcinoma of the lung
- squamous cell carcinoma
- salivary gland-type tumors
-
adenocarcinoma
- pulmonary neuroendocrine tumors
- preinvasive lesions
-
lung cancer invasion patterns
- tumor spread through air spaces (STAS)
- presence of non-lepidic patterns such as acinar, papillary, solid, or micropapillary
- myofibroblastic stroma associated with invasive tumor cells
- pleural invasion
- vascular invasion
- tumors by location
- benign neoplasms
- pulmonary metastases
- lung cancer screening
- lung cancer staging
-
non-small-cell lung cancer