Lymphocytic interstitial pneumonitis
Citation, DOI & article data
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.
Lymphocytic interstitial pneumonitis can occur at any age. However, most of the patients are adults with a mean age of 52-56 years. If a child presents with lymphocytic interstitial pneumonitis, this can be indicative of AIDS.
There is a recognized female predilection (by around 2 fold) 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.
- considered most common lung pathology in these patients 14.
- 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
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.
It is considered a benign lymphoproliferative disorder characterized histologically by diffuse interstitial and alveolar infiltration with polyclonal lymphocytes and plasma cells
In about 80% of patients polyclonal or IgM monoclonal gammopathy is found 8.
Features can be non-specific, but may include:
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. 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. According to some reports 5 year mortality can range between 33-50%.
Transformation to lymphoma can occur, particularly in a patient with monoclonal gammopathy or hypogammaglobulinemia 8. Corticosteroids have been successfully trialled 1.
Approximately 5% of cases may transform to lymphoma 15.
History and etymology
It was originally classified as an idiopathic interstitial pneumonia in 1969 by Liebow and Carrington,
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
- occur in younger females
- cysts are generally uniformly distributed throughout the lungs
Langerhans cell histiocytosis
- bizarre cysts that spare the costophrenic angles
- upper lung zone predominant
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- 10. Cha SI, Fessler MB, Cool CD et-al. Lymphoid interstitial pneumonia: clinical features, associations and prognosis. Eur. Respir. J. 2006;28 (2): 364-9. doi:10.1183/09031936.06.00076705 - Pubmed citation
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- 13. Panchabhai TS, Farver C, Highland KB. Lymphocytic Interstitial Pneumonia. (2016) Clinics in chest medicine. 37 (3): 463-74. doi:10.1016/j.ccm.2016.04.009 - Pubmed
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- 15. Lymphoid Interstitial Pneumonia A Narrative Review - doi:10.1378/chest.122.6.2150