Diffuse lung diseases
Diffuse lung diseases, abbreviated DLD, are a group of uncommon pathologies, also known as idiopathic interstitial pneumonias, abbreviated IIPs, and interstitial lung disease, abbreviated ILD.
They are a subgroup of the medical lung diseases.
Diffuse lung disease is the preferred term, as some diseases lumped into this group have involvement of the alveoli, i.e. are not interstitial. Also, some DLDs are not considered idiopathic, e.g. DIP is caused by smoking.
An introduction to pulmonary pathology is found in the pulmonary pathology article.
Overview
Specimens
- Diffuse lung disease is best assessed on an open biopsy.
- These procedure are quite invasive; thus, not infrequently clinicians will try a transbrochial biopsy that ends-up providing in useful information.
Sign out
LUNG, LEFT, TRANSBRONCHIAL BIOPSY: - SMALL FRAGMENTS OF LUNG PARENCHYMA WITHOUT SIGNIFICANT CHANGES, SEE MICROSCOPIC DESCRIPTION AND COMMENT. COMMENT: The clinical findings are noted. The size and type of biopsy significantly limit the interpretation. Suspected diffuse lung disease (interstitial lung disease) is best assessed on an open lung biopsy.
Micro
The sections show small fragments of lung parenchyma. A very small amount of anthracotic pigment is present. Interstitial fibrosis is not apparent. No granulomata are identified. No nuclear atypia is identified. Air-space macrophages show minimal pigmentation and are not present in large numbers. No significant airspace or interstitial inflammation is identified.
Histologic classification
- Can be complex,[1] and the combined efforts of clinicians, radiologists, and pathologists can help in the generation of a more specific diagnosis.[2][3]
Idiopathic interstitial pneumonia can be subclassified based on histologic appearance into the following patterns:[4][5]
| Histology | Clinical Correlates | Associations |
|---|---|---|
| Desquamative interstitial pneumonia (DIP) | DIP | Smoking |
| Diffuse alveolar damage (DAD) | ARDS, AIP, TRALI | ARDS: trauma, infection; TRALI: blood transfusion; AIP: viral (???) |
| Nonspecific interstitial pneumonia (NSIP) | NSIP | ??? |
| Respiratory bronchiolitis | RB-ILD | Smoking |
| Usual interstitial pneumonia (UIP) | CVD, IPF, drug toxicity, pneumoconiosis | Allergen (hypersensitivity pneumonitis), idiopathic, autoimmune |
| Organizing pneumonia | Cryptogenic organizing pneumonia | autoimmune (???) |
| Lymphocytic interstitial pneumonia (LIP) | LIP | Viral/autoimmune |
ARDS = adult respiratory distress syndrome, AIP = acute interstitial pneumonia, TRALI = transfusion related acute lung injury, CVD = collagen vascular disease, IPF = idiopathic pulmonary fibrosis.
Notes:
- Usual interstitial pneumonia is the most common type of ILD.[6]
Gross pathologic DDx by location
Causes of upper lung fibrosis FASSTEN:[7]
- Farmer's lung.
- Ankylosing spondylitis.
- Sarcoidosis.
- Silicosis.
- Tuberculosis (miliary).
- Eosinophilic granuloma.
- Neurofibromatosis.
Causes of lower lung fibrosis BAD RASH:[7]
- Bronchiolitis obliterans organizing pneumonia (BOOP).
- Asbestosis.
- Drugs (nitrofurantoin, hydralazine, isoniazid (INH), amiodarone).
- Rheumatologic disease.
- Aspiration.
- Scleroderma.
- Hamman-Rich syndrome (really should be -- idiopathic pulmonary fibrosis).
Note:
- Hamman-Rich syndrome is another name for acute interstitial pneumonia.[8]
Specific diseases/pattterns
Diffuse alveolar damage
- Abbreviated DAD.
Main article: Diffuse alveolar damage
Usual interstitial pneumonia
- Abbreviated UIP.
Main article: Usual interstitial pneumonia
Asbestosis
Main article: Asbestosis
Non-specific interstitial pneumonia
- Abbreviated NSIP.
General
- Better prognosis than UIP.
- Some radiologists and pathologists don't believe in this entity.
Associations:[9]
- Connective tissue disease.
- Rheumatoid arthritis.
Gross/Radiology
- No honeycombing.
- Fibrosis usually lower lung zone.
- Patchy ground glass.
Microscopic
Features:[9]
- Diffuse fibrosis:
- Uniform fibrosis (unlike UIP).
- "Linear fibrosis" has a good prognosis - should be mentioned in the report.
- Linear fibrosis = fibrosis that follows alveolar walls + no architectural distortion.
- +/-Lymphoid nodules - association with collagen vascular disease. (???)
- +/-Focal organizing pneumonia.
Notes:
- Inflammation in NSIP usually more prominent than in UIP.
- No honeycombing - key difference between UIP and NSIP.
DDx:
- Collagen vascular disease.
- Drug reaction.
- Hypersensitivity pneumonitis (extrinic allergic alveolitis).
- Lymphocytic interstitial pneumonia (LIP) - much more inflammation.
Organizing pneumonia
Main article: Organizing pneumonia
Hypersensitivity pneumonitis
- AKA extrinsic allergic alveolitis
Main article: Hypersensitivity pneumonitis
Lymphocytic interstitial pneumonia
- Often abbreviated LIP.
General
- Associated with autoimmune disorders (rheumatoid arthritis, pernicious anemia, Sjoegren syndrome)[10] and immunodeficiency.[11]
- Associated with viral infections (HIV, EBV, human T-cell leukemia virus (HTLV) type 1).
- Considered an AIDS-defining diagnosis.[12]
Gross
- Location: basilar predominance.
- Increased interstitial markings.
Microscopic
Features:[13]
- Small mature lymphocytes (usually B cells)[14] in the interstitium of the lung.
- Plasma cells.
- +/-Lymphoid follicles.
Negatives:
- No vasculitis.
- No necrosis.
Images:
DDx:
- Lymphoma.
- Follicular bronchitis/bronchiolitis.
- Nodular lymphoid hyperplasia.
- This is determined in part by radiology; it has nodules radiographically.
Stains
To exclude infection:[15]
- GMS stain -ve.
- Ziehl-Neelsen stain -ve.
IHC
- May be done to exclude lymphoma.
Respiratory bronchiolitis-interstitial lung disease
- Abbreviated RB-ILD or RBILD.
- AKA respiratory bronchiolitis-associated interstitial lung disease.
General
- May be an early version of DIP.
- Associated with smoking.
Microscopic
Features:[16]
- Brown pigmented airspace macrophages - smoker's macrophages - key feature.
- Inflammation of the terminal bronchioles.
Note:
- The histologic features of RBILD may be present peri-tumoural.
DDx:
Image:
Desquamative interstitial pneumonia
- Abbreviated DIP.
General
Microscopic
Features:
- Abundant brown pigmented airspace macrophages - smoker's macrophages - key feature.
- Architecture preserved; "linear fibrosis".
Notes:
- Some fields of view may be indistinguishable from RBILD.
DDx:
- Amiodarone toxicity.
- Fibrotic NSIP.
Images:
Stains
- Macrophages PAS +ve.
See also
References
- ↑ Nicholson AG (November 2002). "Classification of idiopathic interstitial pneumonias: making sense of the alphabet soup". Histopathology 41 (5): 381-91. PMID 12405906. http://www3.interscience.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0309-0167&date=2002&volume=41&issue=5&spage=381.
- ↑ Flaherty KR, King TE, Raghu G, et al (October 2004). "Idiopathic interstitial pneumonia: what is the effect of a multidisciplinary approach to diagnosis?". Am. J. Respir. Crit. Care Med. 170 (8): 904-10. doi:10.1164/rccm.200402-147OC. PMID 15256390. http://ajrccm.atsjournals.org/cgi/pmidlookup?view=long&pmid=15256390.
- ↑ Kim DS, Collard HR, King TE (June 2006). "Classification and natural history of the idiopathic interstitial pneumonias". Proc Am Thorac Soc 3 (4): 285-92. doi:10.1513/pats.200601-005TK. PMID 16738191. http://pats.atsjournals.org/cgi/pmidlookup?view=long&pmid=16738191.
- ↑ Leslie KO, Wick MR. Practical Pulmonary Pathology: A Diagnostic Approach. Elsevier Inc. 2005. ISBN 978-0-443-06631-3.
- ↑ "American Thoracic Society/European Respiratory Society International Multidisciplinary Consensus Classification of the Idiopathic Interstitial Pneumonias. This joint statement of the American Thoracic Society (ATS), and the European Respiratory Society (ERS) was adopted by the ATS board of directors, June 2001 and by the ERS Executive Committee, June 2001". Am. J. Respir. Crit. Care Med. 165 (2): 277-304. January 2002. PMID 11790668. http://ajrccm.atsjournals.org/cgi/pmidlookup?view=long&pmid=11790668.
- ↑ Visscher DW, Myers JL (June 2006). "Histologic spectrum of idiopathic interstitial pneumonias". Proc Am Thorac Soc 3 (4): 322-9. doi:10.1513/pats.200602-019TK. PMID 16738196. http://pats.atsjournals.org/cgi/pmidlookup?view=long&pmid=16738196.
- ↑ 7.0 7.1 Yeung, J.C.; Leonard, Blair J. N. (2005). The Toronto Notes 2005 - Review for the MCCQE and Comprehensive Medical Reference (2005 ed.). The Toronto Notes Inc. for Medical Students Inc.. pp. R13. ISBN 978-0968592854.
- ↑ Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 90. ISBN 978-0781765275.
- ↑ 9.0 9.1 Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 92. ISBN 978-0781765275.
- ↑ URL: http://emedicine.medscape.com/article/299643-overview. Accessed on: 2 June 2010.
- ↑ Nicholson AG (August 2001). "Lymphocytic interstitial pneumonia and other lymphoproliferative disorders in the lung". Semin Respir Crit Care Med 22 (4): 409–22. doi:10.1055/s-2001-17384. PMID 16088689.
- ↑ Turner, BJ.; Eppes, S.; McKee, LJ.; Cosler, L.; Markson, LE. (Jan 1995). "A population-based comparison of the clinical course of children and adults with AIDS.". AIDS 9 (1): 65-72. PMID 7893443.
- ↑ URL: http://emedicine.medscape.com/article/299643-diagnosis. Accessed on: 2 June 2010.
- ↑ AFIP atlas of nontumour pathology. 2002. Vo. 2. P.265. ISBN 1-881041-79-4.
- ↑ URL: http://path.upmc.edu/cases/case176/dx.html. Accessed on: 8 January 2012.
- ↑ Leslie, Kevin O.; Wick, Mark R. (2004). Practical Pulmonary Pathology: A Diagnostic Approach (1st ed.). Churchill Livingstone. pp. 197-8. ISBN 978-0443066313.
- ↑ Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 93. ISBN 978-0781765275.