Pathology of interstitial lung disease

Hypersensitivity Pneumonitis: Updates in Evaluation, Management, and Ongoing Dilemmas

Hypersensitivity pneumonitis (HP) is a heterogenous disease entity characterized by an aberrant immune response to inhalational antigens. Disease modification hinges on early antigen remediation with a goal to attenuate immune dysregulation. Disease severity and progression are mediated by an interface between degree, type and chronicity of exposure, genetic predisposition, and biochemical properties of the inducing agent. Guidelines have provided a standardized approach; however, decision-making remains with many clinical dilemmas. The delineation of fibrotic and nonfibrotic HP is crucial to identify the differences in clinical trajectories, and further clinical trials are needed to understand optimal therapeutic strategies.

Lung Ultrasound Artifacts Interpreted as Pathology Footprints

Background: The original observation that lung ultrasound provides information regarding the physical state of the organ, rather than the anatomical details related to the disease, has reinforced the idea that the observed acoustic signs represent artifacts. However, the definition of artifact does not appear adequate since pulmonary ultrasound signs have shown valuable diagnostic accuracy, which has been usefully exploited by physicians in numerous pathologies. Method: A specific method has been used over the years to analyze lung ultrasound data and to convert artefactual information into anatomical information. Results: A physical explanation of the genesis of the acoustic signs is provided, and the relationship between their visual characteristics and the surface histopathology of the lung is illustrated. Two important sources of potential signal alteration are also highlighted. Conclusions: The acoustic signs are generated by acoustic traps that progressively release previously trapped energy. Consequently, the acoustic signs highlight the presence of acoustic traps and quantitatively describe their distribution on the lung surface; they are not artifacts, but pathology footprints and anatomical information. Moreover, the impact of the dynamic focusing algorithms and the impact of different probes on the visual aspect of the acoustic signs should not be neglected.

Artifactual Lung Ultrasonography: It Is a Matter of Traps, Order, and Disorder

When inspecting the lung with standard ultrasound B-mode imaging, numerous artifacts can be visualized. These artifacts are useful to recognize and evaluate several pathological conditions in Emergency and Intensive Care Medicine. More recently, the interest of the Pulmonologists has turned to the echographic study of the interstitial pathology of the lung. In fact, all lung pathologies which increase the density of the tissue, and do not consolidate the organ, are characterized by the presence of ultrasound artifacts. Many studies of the past have only assessed the number of vertical artifacts (generally known as B-Lines) as a sign of disease severity. However, recent observations suggest that the appearance of the individual artifacts, their variability, and their internal structure, may play a role for a non-invasive characterization of the surface of the lungs, directing the diagnoses and identifying groups of diseases. In this review, we discuss the meaning of lung ultrasound artifacts, and introduce hypothesis on the correlation between their presence and the structural variation of the sub-pleural tissue in light of current knowledge of the acoustic properties of the pleural plane.

Magnetic resonance imaging of interstitial lung diseases: A state-of-the-art review

Magnetic resonance imaging (MRI) has been emerging as an imaging modality to assess interstitial lung diseases (ILD). An optimal chest MRI protocol for ILDs should include non-contrast breath-holding sequences, steady-state free-precession sequences, and contrast-enhanced sequences. One of the main MRI applications in ILDs is the differentiation between areas of active inflammation (i.e. reversible stage) and fibrosis. Alveolitis presents high signal intensity on T2-weighted sequences (WS) and early-enhancement on contrast-enhanced MR sequences, while fibrotic-predominant lesions present low signal and late-enhancement in these sequences, respectively. MRI can be useful in connective tissue diseases, idiopathic pulmonary fibrosis, and sarcoidosis. The aim of this state-of-the-art review was to perform a state-of-the-art review on the use of MRI in ILDs, and propose the optimal MRI protocols for imaging ILDs.

Reprint of: The pathology of pulmonary sarcoidosis: update

Sarcoidosis is a multi-system disease of unknown etiology, usually affecting the respiratory tract and other organs, and is characterized by the formation of nonnecrotizing epithelioid granulomas. The diagnosis depends on a combination of a typical clinicoradiological presentation, the finding of nonnecrotizing epithelioid granulomas in a tissue biopsy, and exclusion of other possible diseases, especially those of infectious etiology. The granulomas contain epithelioid cells, giant cells, CD4+ T cells in their center, and CD8+ T lymphocytes and B lymphocytes at their periphery. The granulomas are present in a lymphatic pattern around bronchovascular structures and, because of this, may show angioinvasion. The bronchial involvement produces a high diagnostic yield for transbronchial and endobronchial biopsies in this disease. Finally, small amounts of fibrinoid necrosis may occur within granulomas of sarcoidosis and do not exclude the diagnosis. Larger amounts suggest either infection or the rare disease necrotizing sarcoid granulomatosis (NSG). A number of cytoplasmic structures/inclusions can be identified within the granulomas of sarcoidosis, including asteroid bodies, Schaumann's bodies, calcium oxalate crystals, and Hamazaki-Wesenberg bodies; the last two of these can cause difficulties in differential diagnosis. Extra-pulmonary sarcoid can be an important factor in prognosis. Involved sites include (in decreasing frequency): skin, endocrine organs, extra-thoracic lymph nodes, neurologic sites, eyes, liver, spleen, bone marrow, cardiac, ear/nose/throat, parotid/salivary, muscles, bones/joint, and kidney. NSG is a controversial variant of sarcoidosis consisting of granulomatous pneumonitis with sarcoid-like granulomas, variable amounts of necrosis, and granulomatous vasculitis. The lesions are most often confined to lung, and they usually appear as multiple nodules or nodular infiltrates, but occasionally as solitary or unilateral nodules ranging up to 5 cm in diameter. Nodular sarcoidosis is rare, varying from 1.6% to 4% of patients with sarcoidosis, and, as the name suggests, it shows radiographic nodules measuring 1 to 5 cm in diameter that typically consist of coalescent granulomas. Lung transplantation can be used in selected patients with fibrotic late-stage sarcoidosis. There is a high reported frequency of recurrence of disease in the pulmonary allograft, ranging from 47% to 67%, but recurrence is usually not clinically significant. Studies of the pathogenesis of sarcoidosis suggest that it is a chronic immunological response produced by a genetic susceptibility and exposure to specific environmental factors.

Atypical cells in pathology of endobronchial ultrasound-guided transbronchial biopsy of peripheral pulmonary lesions: incidence and clinical significance

BACKGROUND

Atypical cells may occasionally be the only pathologic finding in radial-probe endobronchial ultrasound (EBUS)-guided transbronchial biopsy (TBB) of peripheral pulmonary lesions (PPLs); however, it is uncertain how often we encounter such a situation and what clinical features can be used to identify these ambiguous PPLs, which are more likely to be malignant.

METHODS

From 2009 to 2016, consecutive patients referred for EBUS-guided TBB of PPLs and with pathology reports indicating atypical cells alone were included. Medical records were reviewed to extract patient demographics, clinical characteristics, procedural details and complications. The primary outcome was the final diagnosis of the PPLs on subsequent investigation. Multivariate logistic regression analysis was used to identify independent factors associated with a final malignant diagnosis.

RESULTS

One hundred sixty-five (7.2%) of 2291 patients had non-diagnostic TBB showing atypical cells. Benign and malignant diagnoses were subsequently obtained in 45 (27%) and 120 (73%) patients, respectively. The leading malignancy was lung adenocarcinoma; of note, a variety of benign lesions revealed cellular atypia on pathology, in particular, chronic inflammation, tuberculosis and pneumonia. Multivariate analysis indicated lesion appearance [solid vs. others; odds ratio (OR) 7.93; 95% confidence interval (CI) 2.94-21.40; P < 0.001] and probe position (adjacent to vs. within; OR 3.36; 95% CI 1.11-10.15; P = 0.032) were two significant factors predictive of a final diagnosis of malignancy.

CONCLUSIONS

One out of 14 EBUS-guided TBB procedures for PPLs exhibited atypical cells on pathology. Meticulous management strategies should be formulated to deal with these instances after taking into consideration lesion appearance, probe position and patient preferences.

Toxicity of Smokeless Tobacco Extract after 184-Day Repeated Oral Administration in Rats

The use of smokeless tobacco (ST) is growing rapidly and globally. The consumption of ST is associated with an increased risk for developing chronic diseases, such as diabetes, hypercholesterolemia, and myocardial infarction, and has led to many public health problems. It is very important to access the toxicity of ST. This experiment presents data from 184-day toxicology studies in Sprague-Dawley (SD) rats designed to characterize the chronic effects of a smokeless tobacco extract (STE). The control group and treatment groups were matched for a range of nicotine levels. Animals were given STE by oral gavage with doses of 3.75 (low-dose), 7.50 (mid-dose) and 15.00 (high-dose) mg·nicotine/kg body weight/day for 184 days, followed by 30 days for recovery. Variables evaluated included body weights, feed consumption, clinical observations, clinical and anatomic pathology (including organ weights), and histopathology. Decreased body weights and organ weights (heart, liver and kidney) were found in animals in the mid-dose and high-dose groups. STE also showed moderate and reversible toxicity in esophagus, stomach, liver, kidney and lung.

Usefulness of the second heart sound for predicting pulmonary hypertension in patients with interstitial lung disease

CONTEXT AND OBJECTIVE

P2 hyperphonesis is considered to be a valuable finding in semiological diagnoses of pulmonary hypertension (PH). The aim here was to evaluate the accuracy of the pulmonary component of second heart sounds for predicting PH in patients with interstitial lung disease.

DESIGN AND SETTING

Cross-sectional study at the University of Brasilia and Hospital de Base do Distrito Federal.

METHODS

Heart sounds were acquired using an electronic stethoscope and were analyzed using phonocardiography. Clinical signs suggestive of PH, such as second heart sound (S2) in pulmonary area louder than in aortic area; P2 > A2 in pulmonary area and P2 present in mitral area, were compared with Doppler echocardiographic parameters suggestive of PH. Sensitivity (S), specificity (Sp) and positive (LR+) and negative (LR-) likelihood ratios were evaluated.

RESULTS

There was no significant correlation between S2 or P2 amplitude and PASP (pulmonary artery systolic pressure) (P = 0.185 and 0.115; P= 0.13 and 0.34, respectively). Higher S2 in pulmonary area than in aortic area, compared with all the criteria suggestive of PH, showed S = 60%, Sp= 22%; LR+ = 0.7; LR- = 1.7; while P2> A2 showed S= 57%, Sp = 39%; LR+ = 0.9; LR- = 1.1; and P2 in mitral area showed: S= 68%, Sp = 41%; LR+ = 1.1; LR- = 0.7. All these signals together showed: S= 50%, Sp = 56%.

CONCLUSIONS

The semiological signs indicative of PH presented low sensitivity and specificity levels for clinically diagnosing this comorbidity.

Idiopathic Pulmonary Fibrosis: A Study of 46 Patients from Western India: Clinical Presentations and Survival

OBJECTIVES

Idiopathic pulmonary fibrosis (IPF) is the most common form of interstitial lung disease (ILD) diagnosed all over the world as well as in India. The objective was to study the clinical presentations, treatment options, and survival of patients diagnosed with IPF.

MATERIALS AND METHODS

This was a 6-year retrospective observational study. All patients diagnosed with ILD underwent a comprehensive evaluation to confirm the diagnosis of IPF and were subsequently included in the study. Clinical data and laboratory data were recorded. Patients were treated as per current guidelines.

RESULTS

Out of the total number of patients (n=123) diagnosed with ILD, 46 (37.4%) patients were included in the study [Males, n=19 (41%) and females, n=27 (59%)]. Sixty-seven percent (n=31) of the patients were in the age group of 61-80 years. The mean age of males and females was 68.36 and 66.25 years, respectively. Clubbing was observed in 67% (n=29) of the patients. The mean forced vital capacity (FVC) was 52%. High-resolution computed tomography (HRCT) of the chest showed a definite usual interstitial pneumonia (UIP) pattern of honeycombing in 60% (n=28) of the patients. Desaturation on a 6 min walk distance was noted in 60% (n=28) of the patients. Ten patients wrongly received-anti tuberculosis treatment (21%) before they were diagnosed with IPF. The median delay in diagnosis was 20 months. The 5-year survival rate was 25%; the average survival was 39 months. Patients receiving pirfenidone showed a survival benefit compared with those having received triple therapy. Survival in IPF was significantly low compared with that in other ILDs. Twenty-four (52%) patients died during the study.

CONCLUSION

IPF is a disease which affects the fourth to seventh decade of the Indian population with low survival.

Lung volume quantified by MRI reflects extracellular-matrix deposition and altered pulmonary function in bleomycin models of fibrosis: effects of SOM230

Idiopathic pulmonary fibrosis is a progressive and lethal disease, characterized by loss of lung elasticity and alveolar surface area, secondary to alveolar epithelial cell injury, reactive inflammation, proliferation of fibroblasts, and deposition of extracellular matrix. The effects of oropharyngeal aspiration of bleomycin in Sprague-Dawley rats and C57BL/6 mice, as well as of intratracheal administration of ovalbumin to actively sensitized Brown Norway rats on total lung volume as assessed noninvasively by magnetic resonance imaging (MRI) were investigated here. Lung injury and volume were quantified by using nongated or respiratory-gated MRI acquisitions [ultrashort echo time (UTE) or gradient-echo techniques]. Lung function of bleomycin-challenged rats was examined additionally using a flexiVent system. Postmortem analyses included histology of collagen and hydroxyproline assays. Bleomycin induced an increase of MRI-assessed total lung volume, lung dry and wet weights, and hydroxyproline content as well as collagen amount. In bleomycin-treated rats, gated MRI showed an increased volume of the lung in the inspiratory and expiratory phases of the respiratory cycle and a temporary decrease of tidal volume. Decreased dynamic lung compliance was found in bleomycin-challenged rats. Bleomycin-induced increase of MRI-detected lung volume was consistent with tissue deposition during fibrotic processes resulting in decreased lung elasticity, whereas influences by edema or emphysema could be excluded. In ovalbumin-challenged rats, total lung volume quantified by MRI remained unchanged. The somatostatin analog, SOM230, was shown to have therapeutic effects on established bleomycin-induced fibrosis in rats. This work suggests MRI-detected total lung volume as readout for tissue-deposition in small rodent bleomycin models of pulmonary fibrosis.

Treatment of Acute Silicoproteinosis by Whole-Lung Lavage

Acute silicoproteinosis is a rare disease that occurs following a heavy inhalational exposure to silica dusts. Clinically, it resembles pulmonary alveolar proteinosis (PAP); silica exposure is thought to be a cause of secondary PAP. We describe a patient with biopsy-confirmed acute silicoproteinosis whose course was complicated by acute hypoxemic respiratory failure requiring mechanical ventilation. Without clinical improvement despite antibiotic and steroid treatment, the patient was scheduled for whole-lung lavage under general anesthesia. Anesthetic challenges included double-lumen tube placement and single-lung ventilation in a hypoxic patient, facilitating lung lavage, and protecting the contralateral lung from catastrophic spillage.

Familial Idiopathic Interstitial Pneumonia: Histopathology and Survival in 30 Patients

Context.—Familial idiopathic interstitial pneumonia (F-IIP) describes the unexplained occurrence of diffuse parenchymal lung disease in related individuals. Prevailing wisdom suggests that the histopathology of F-IIP is indistinguishable from that of idiopathic pulmonary fibrosis, namely, usual interstitial pneumonia (UIP).

Objective.—To define the histopathology of F-IIP in lung tissue samples.

Design.—Tissue sections from 30 patients with F-IIP, enrolled in a national research program, were evaluated by 3 pulmonary pathologists using 15 predefined histopathologic features. Each feature was recorded independently before a final diagnosis was chosen from a limited list dichotomized between UIP or “not UIP.” These 2 groups were then compared to survival.

Results.—The consensus diagnosis for the F-IIP cohort was an unclassifiable parenchymal fibrosis (60%), with a high incidence of histopathologic honeycombing, fibroblast foci, and smooth muscle in fibrosis. Usual interstitial pneumonia, strictly defined, was identified in less than half of the F-IIP cases (range, 23%–50%). Interobserver agreement was fair (κ  =  0.37) for 2 observers for the overall diagnosis of UIP. Findings unexpected in UIP were prevalent. The survival for the entire F-IIP cohort was poor, with an estimated mortality of 93% and a median age at death of 60.9 years. Subjects with UIP had a shorter survival and younger age at death.

Conclusions.—Pulmonary fibrosis was the dominant histopathology identified in our patients, but diagnostic features of UIP were seen in less than 50% of the samples. Overall survival was poor, with mortality accelerated apparently by the presence of a UIP pattern of disease.

Padrões tomográficos das doenças intersticiais pulmonares difusas com correlação clínica e patológica

A tomografia de alta resolução (TCAR) é a técnica de imagem radiológica que reflete mais de perto as alterações da estrutura pulmonar. Os vários achados tomográficos podem ser combinados para formar padrões típicos. Estes, conjuntamente com a distribuição anatômica dos achados, e com os dados clínicos, podem estreitar o diagnóstico das doenças intersticiais pulmonares difusas, e em vários casos sugerir o diagnóstico correto com alto grau de acurácia. Os padrões mais comuns das doenças intersticiais pulmonares difusas na TCAR são o nodular, linear e reticular, lesões císticas, opacidades em vidro fosco e consolidações. Este artigo revisa as correlações entre os padrões tomográficos na TCAR e os achados patológicos e resume as causas mais comuns e os métodos de investigação para se atingir um diagnóstico nas doenças pulmonares crônicas difusas mais comuns.

The pathology of pulmonary sarcoidosis: update

Sarcoidosis is a multi-system disease of unknown etiology, usually affecting the respiratory tract and other organs, and is characterized by the formation of nonnecrotizing epithelioid granulomas. The diagnosis depends on a combination of a typical clinicoradiological presentation, the finding of nonnecrotizing epithelioid granulomas in a tissue biopsy, and exclusion of other possible diseases, especially those of infectious etiology. The granulomas contain epithelioid cells, giant cells, CD4+ T cells in their center, and CD8 + T lymphocytes and B lymphocytes at their periphery. The granulomas are present in a lymphatic pattern around bronchovascular structures and, because of this, may show angioinvasion. The bronchial involvement produces a high diagnostic yield for transbronchial and endobronchial biopsies in this disease. Finally, small amounts of fibrinoid necrosis may occur within granulomas of sarcoidosis and do not exclude the diagnosis. Larger amounts suggest either infection or the rare disease necrotizing sarcoid granulomatosis (NSG). A number of cytoplasmic structures/inclusions can be identified within the granulomas of sarcoidosis, including asteroid bodies, Schaumann's bodies, calcium oxalate crystals, and Hamazaki-Wesenberg bodies; the last two of these can cause difficulties in differential diagnosis. Extra-pulmonary sarcoid can be an important factor in prognosis. Involved sites include (in decreasing frequency): skin, endocrine organs, extra-thoracic lymph nodes, neurologic sites, eyes, liver, spleen, bone marrow, cardiac, ear/nose/throat, parotid/ salivary, muscles, bones/joint, and kidney. NSG is a controversial variant of sarcoidosis consisting of granulomatous pneumonitis with sarcoid-like granulomas, variable amounts of necrosis, and granulomatous vasculitis. The lesions are most often confined to lung, and they usually appear as multiple nodules or nodular infiltrates, but occasionally as solitary or unilateral nodules ranging up to 5 cm in diameter. Nodular sarcoidosis is rare, varying from 1.6% to 4% of patients with sarcoidosis, and, as the name suggests, it shows radiographic nodules measuring 1 to 5 cm in diameter that typically consist of coalescent granulomas. Lung transplantation can be used in selected patients with fibrotic late-stage sarcoidosis. There is a high reported frequency of recurrence of disease in the pulmonary allograft, ranging from 47% to 67%, but recurrence is usually not clinically significant. Studies of the pathogenesis of sarcoidosis suggest that it is a chronic immunological response produced by a genetic susceptibility and exposure to specific environmental factors.

Diagnosis of interstitial lung diseases

Interstitial lung diseases (ILDs), a broad heterogeneous group of parenchymal lung disorders, can be classified into those with known and unknown causes. The definitions and diagnostic criteria for several major forms of ILDs have been revised in recent years. Although well over 100 distinct entities of ILDs are recognized, a limited number of disorders, including idiopathic pulmonary fibrosis, sarcoidosis, and connective tissue disease-related ILDs, account for most ILDs encountered clinically. In evaluating patients with suspected ILD, the clinician should confirm the presence of the disease and then try to determine its underlying cause or recognized clinicopathologic syndrome. Clues from the medical history along with the clinical context and radiologic findings provide the initial basis for prioritizing diagnostic possibilities for a patient with ILD. High-resolution computed tomography of the chest has become an invaluable tool in the diagnostic process. A confident diagnosis can sometimes be made on the basis of high-resolution computed tomography and clinical context. Serologic testing can be helpful in selected cases. Histopathologic findings procured through bronchoscopic or surgical lung biopsy are often needed in deriving a specific diagnosis. An accurate prognosis and optimal treatment strategy for patients with ILDs depend on an accurate diagnosis, one guided by recent advances in our understanding of the causes and pathogenetic mechanisms of ILDs.

Clinical review: Idiopathic pulmonary fibrosis—Past, present and future

Idiopathic pulmonary fibrosis (IPF) is an important, and devastating, interstitial lung disease. It has a median mortality of only 3 years, worse than many cancers, and its incidence continues to rise. In this article, an overview of key developments in our understanding and clinical management of IPF will be provided.

Pulmonary Pathology for the Clinician

The idiopathic interstitial pneumonias are a group of diffuse parenchymal lung diseases that manifest varying patterns of inflammation and fibrosis histopathologically. These disorders are classified most accurately by the combination of histopathology on lung biopsy with clinical and radiographic findings. A pattern-based approach to the histopathology of the lung biopsy, as examined at low magnification, immediately helps narrow the diagnostic possibilities. The technique can be applied by pulmonologists and pathologists in assembling a cogent differential diagnosis. More subtle histopathologic findings in the biopsy (eg, granulomas, necrosis, eosinophils) help narrow this differential. This pattern-based histopathologic technique fosters close interaction between pulmonologists and general pathologists during the evaluation of the patient who has interstitial lung disease and has undergone surgical biopsy.