In the past, the term usual interstitial pneumonia was used synonymously with idiopathic pulmonary fibrosis. However more recently the term idiopathic pulmonary fibrosis has been applied solely to the clinical syndrome associated with the morphologic pattern of UIP, with the specific exclusion of entities such as non-specific interstitial pneumonia NSIP and desquamative interstitial pneumonia DIP 1.
The histological diagnosis of UIP is based on temporal and spatial heterogeneity, which is the identification of fibrotic lesions at different stages fibroblastic infiltrates, mature fibrosis, and honeycombing within the same biopsy specimen and architectural distortion.
On a typical biopsy, there are areas of normal lung alternating with interstitial fibrosis and honeycombing. The distribution of UIP characteristically is with an apicobasal gradient with basal and peripheral subpleural predominance, although it is often patchy. UIP pattern of ILD can be seen in idiopathic pulmonary fibrosis or secondary to underlying systemic diseases. These would include:. In practice, the diagnosis is usually made in a multidisciplinary approach involving chest physicians, radiologists and pathologists with expertise in interstitial lung disease ILD Plain film features are non-specific.
While chest radiographs can be even normal in patients with very early disease, in advanced disease, it may show decreased lung volumes and basal fine to coarse reticulation.
Usually, due to the more extensive involvement of the lower lobes, the major fissure is shifted inferiorly which is best seen on the lateral chest radiograph.
Similar to the pathology specimen, cross-sectional imaging also reveals heterogeneity, with patchy areas of fibrosis alternating with areas of normal lung 5. In recent times some authors have suggested certain signs within a UIP pattern more suggestive of it being due to connective tissue disorder interstitial lung disease over IPF In patients with UIP, areas of ground-glass attenuation tend to increase in extent or progress to fibrosis despite treatment 8, In those with more active inflammation involving the pulmonary interstitium, there is a faster progression of honeycombing in long-term follow-up The average rate of progression of honeycombing in patients with idiopathic usual interstitial pneumonia according to one study was 0.
Please Note: You can also scroll through stacks with your mouse wheel or the keyboard arrow keys. Updating… Please wait. Unable to process the form. Check for errors and try again. Thank you for updating your details. Log In. In subacute disease HP will present with OP, but focally florid lesions often can be seen.
In contrast to autoimmune disease pleuritis is absent. Note the dense lymphocytic infiltration into the myofibroblastic focus top ; at the bottom vasculopathy is seen with myxoid changes of the intima and narrowing of the arterial lumen.
SLE, a overview, b alveolar hemorrhage and vasculitis with thrombosis c and infarct; d shows eosinophilic deposits simulating amyloid, but this corresponded to immune complexes e. Dermatomyositis, in this case the UIP pattern with myofibroblastic foci is not easily detected upper panel , but these are highlighted by Movat stain lower panel ; there is fibrosis, cystic remodeling, but also BALT hyperplasia and sclerosis of pulmonary arteries.
NSIP, cellular upper, fibrotic lower panel; note the mixed infiltration by lymphocytes, plasma cells and histiocytes. Organizing pneumonia with many granulation polyps; note the newly formed blood vessels within these polyps. Chronic hypersensitivity pneumonia, a inflammatory infiltrates and cystic remodeling is seen, in b BALT hyperplasia and fibrosis, in c myofibroblastic foci and lymphocytic infiltrations, in d fibrosis, lymphocytes and multinucleated giant cells; e shows cystic remodeling and bronchiolar metaplasia, in f and h ill formed granulomas and giant cells are seen; in g massive sclerosis of a pulmonary artery next to an old myofibroblastic focus are found.
Pathologists can arrive not only at a descriptive diagnosis, i. Cryobiopsy and BAL is not recommended. The diagnosis should be made by a board. There is a nice report on the results of such recommendations. During a meeting of pulmonologists, radiologists and pathologists each group had to analyze cases of proven IPF.
When pulmonologists analyzed the cases there was a low k-value amongst them 0. The same applied to the radiologists. There was also a major discrepancy between clinicians in academic centers and community hospitals. When both groups merged, there was still no good correlation. When the pathologic diagnosis was disclosed, the k-value reached 0. What does that mean, if pathology is no longer the gold standard Raghu et al. In my personnel experience, there is a minority of IPF cases, which are correctly diagnosed by clinical and radiological data alone.
Myofibroblastic foci cannot be seen on CT scan. Fibrosis is not always a sign of IPF — many other diseases will cause fibrosis.
Having the ability to see many consultation cases, there is a lot more to dig out of the morphology, than just UIP. This all escapes, if no more tissues are taken. On the other hand, pathologists have not done a good job by just handing over a description UIP , instead of raising the question of the underlying etiology. So we have to learn and improve too!
What does that mean for consensus classification? I think all available data need to be discussed, and controversies upon the diagnosis need to be critically reviewed with these data.
After such a critical review, a final diagnosis might be achieved for most cases, but cases with contradictory findings in pathology, radiology, and clinics should kept open for close follow-up of the patient. Chest — PubMed Google Scholar. Stem Cell Res Ther Transl Res — Eur Respir J — Individualization of a clinicopathologic entity in a series of 12 patients.
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An integral model. Semin Respir Crit Care Med — Am J Hum Genet — Rheumatol Int — Download references. The authors would like to thank the members of the different pulmology and pathology departments for sharing their cases for a second opinion and thus enabling me to gain expertise in this diseases.
My special thanks go to the Departments of Pulmology and Pathology at the Hospital Munich-Bogenhausen for the many years of collaborations. You can also search for this author in PubMed Google Scholar. The author planned the review, selected the cases and figures. The author s read and approved the final manuscript.
Correspondence to Helmut H. The use of tissues and patient data has been approved by the Ethics Committee of the Medical University, No. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material.
If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. Reprints and Permissions. Popper, H. Fibrosing pneumonia — how to diagnose, and how to recognize the etiology?. Surg Exp Pathol 3, 15 Download citation. Received : 30 December Accepted : 30 June Published : 29 July Anyone you share the following link with will be able to read this content:.
Sorry, a shareable link is not currently available for this article. Try out PMC Labs and tell us what you think. Learn More. There are many ways in which a set of biological variables clinical, laboratory, or histological variables can characterize a distinct disease. In modern medicine, a nosological entity is most commonly determined by the primary factor responsible for the disease. Nevertheless, when the etiologic factor is unknown, a syndromic approach is the surrogate approach for establishing a diagnosis.
Typically, guidelines on a given subject gather the most relevant information available at the time, providing an excellent opportunity for a critical analysis of the subject in question. In this context, we would like to spark off a debate by asking the following question: would UIP be considered a disease in its own right if the accumulated evidence were viewed in a different light?
Because UIP has such a peculiar histological pattern, chest HRCT is able to predict the histological features of UIP with a great degree of confidence in some typical cases, dispensing with a biopsy.
The uniqueness of UIP is determined by the process of fibrosis formation peripheral, with temporal and spatial heterogeneity, and minimal inflammation. It is a maladaptive repair process regardless of whether it is idiopathic or related to other diseases. However, from a nosological point of view, the real difference between UIP related to other conditions such as collagen vascular diseases and hypersensitivity pneumonitis and its "idiopathic" form is unclear. We should now turn back to our initial considerations.
When proposing that UIP be considered a disease in its own right, we took into consideration the characteristics that define a nosological entity. The histological features of UIP are distinctive enough to characterize a disease:. A disease of the lung repair process, UIP results in a peculiar form of fibrotic deposition, regardless of its relationship with other diseases such information, i. This peculiar form of fibrotic deposition can be diagnosed by histology and chest HRCT.
All of the abovementioned features are sufficient to characterize a disease in modern medicine, although the complete pathogenesis of UIP has yet to be fully understood.
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