Pathological diagnosis of granulomatous lung disease: a review

Navigating the Maze: Exploring Non-Oncological Complexities in Non-Small-Cell Lung Cancer

Pulmonary oncological pathologies are an important public health problem and the association with other pulmonary lesions may pose difficulties in diagnosis and staging or require different treatment options. To address this complexity, we conducted a retrospective observational study at the Marius Nasta Institute of Pneumophthisiology, Bucharest, Romania. Our study focused on patients admitted in 2019 with non-small-cell lung carcinoma and associated pulmonary lesions identified through surgical resection specimens. Among the 314 included patients, multiple pulmonary nodules were observed on macroscopic examination, with 12% (N = 37) exhibiting nonmalignant etiologies upon microscopic examination. These findings underscore the challenge of preoperative staging. Patients with coexisting nonmalignant lesions were similar in age, smoking habits, and professional or environmental exposure by comparison with those who presented only malignant lesions. The presentation of coexisting malignant and nonmalignant lesions may pose difficulties in diagnosing and staging pulmonary cancer.

Pulmonary Histoplasmosis Complicated by Nonvalvular Right Ventricular Wall Histoplasma capsulatum Endocarditis

Histoplasmosis is commonly a self-limited fungal disease that primarily affects the lung and reticuloendothelial system. Cardiac involvement by histoplasmosis is uncommon. In this report, we provide a detailed description of severe pulmonary histoplasmosis complicated by the disease involvement of the free wall of the right ventricle. A 55-year-old female presented with cough, fevers, dyspnea, and 30-pound unintentional weight loss in 6 months. Her past medical history was significant for supraventricular tachycardia with permanent pacemaker implantation. Imaging studies revealed an intracardiac mass accompanied by mediastinal lymphadenopathy and bilateral lung nodules. Endobronchial ultrasound-guided transbronchial needle aspiration of station 4R lymph nodes revealed numerous yeast forms, morphologically consistent with Histoplasma capsulatum. The diagnosis was further corroborated by the elevated titers of serum antibodies against Histoplasma capsulatum. The right ventricular mass debulking with biopsy showed necrotizing granulomatous inflammation involving nonvalvular endocardium and myocardium of the free wall of the right ventricle. The report documents an unusual presentation of pulmonary histoplasmosis accompanied by nonvalvular endocarditis and suggests a possible association between the site of the cardiac infection and the presence of a permanent intravascular pacer device.

CRDet: A circle representation detector for lung granulomas based on multi-scale attention features with center point calibration

Lung granuloma is a very common lung disease, and its specific diagnosis is important for determining the exact cause of the disease as well as the prognosis of the patient. And, an effective lung granuloma detection model based on computer-aided diagnostics (CAD) can help pathologists to localize granulomas, thereby improving the efficiency of the specific diagnosis. However, for lung granuloma detection models based on CAD, the significant size differences between granulomas and how to better utilize the morphological features of granulomas are both critical challenges to be addressed. In this paper, we propose an automatic method CRDet to localize granulomas in histopathological images and deal with these challenges. We first introduce the multi-scale feature extraction network with self-attention to extract features at different scales at the same time. Then, the features will be converted to circle representations of granulomas by circle representation detection heads to achieve the alignment of features and ground truth. In this way, we can also more effectively use the circular morphological features of granulomas. Finally, we propose a center point calibration method at the inference stage to further optimize the circle representation. For model evaluation, we built a lung granuloma circle representation dataset named LGCR, including 288 images from 50 subjects. Our method yielded 0.316 mAP and 0.571 mAR, outperforming the state-of-the-art object detection methods on our proposed LGCR.

Diagnostic algorithm allows for a scientifically robust and reliable retrospective diagnosis using textual evidence from mid-19th century Basel, Switzerland

OBJECTIVE

Diagnosing disease from the past using historic textual sources can be controversial as to its accuracy. To overcome these objections, an empirical approach to the historical clinical data was developed. The approach follows a standardised, objective, and systematic evaluation, satisfying the requirements of the philosophy of science.

MATERIAL

Physician-managed medical records of mid-19th century patients reported to have suffered from tuberculosis.

METHOD

A diagnostic algorithm, quantifying clinical data into a scoring system, was developed based on criteria recorded in the medical sources. The findings were compared to the autopsy results using the Receiver Operating Characteristics method.

RESULTS

The generated scoring system correctly predicted the diagnosis of tuberculosis in 86% of patients in the study. 6% false negatives and 8% false positives were predicted.

CONCLUSIONS

It is possible to retrospectively diagnose in a reliable and scientifically robust manner under certain conditions. It is important to embed the clinical data into the historical context. A general rejection of retrospective diagnosis is unsubstantiated. Well-designed, disease-specific, and source adapted medical scoring systems are new approaches and overcome criticism raised against retrospective diagnosis.

SIGNIFICANCE

This new approach utilises diverse historic sources and potentially leads to reliable retrospective diagnosis of most common diseases of the past.

LIMITATIONS

Selection bias of the records allocated. Quality of the historic sources utilized. Restricted statistical assessment potential of historic sources.

SUGGESTIONS FOR FURTHER RESEARCH

Development of disease- and epoch-specific medical score systems.

Primary biliary cholangitis presenting with granulomatous lung disease misdiagnosed as lung cancer: A case report

BACKGROUND

There are few cases of pulmonary granulomatous changes secondary to primary biliary cirrhosis (PBC). No case of granulomatous lung disease secondary to PBC misdiagnosed as lung cancer had been reported.

CASE SUMMARY

A middle-aged woman presented with lung nodules and was misdiagnosed with lung cancer by positron emission tomography/computed tomography. She underwent left lobectomy, and the pathology of the nodules showed granulomatous inflammation, which was then treated with antibiotics. However, a new nodule appeared. Further investigation with lung biopsy and liver serology led to the diagnosis of PBC, and chest computed tomography indicated significant reduction in the pulmonary nodule by treatment with methylprednisolone and ursodeoxycholic acid.

CONCLUSION

Diagnosis of pulmonary nodules requires integrating various clinical data to avoid unnecessary pulmonary lobectomy.

Neutrophil S100A9 supports M2 macrophage niche formation in granulomas

Mycobacterium infection gives rise to granulomas predominantly composed of inflammatory M1-like macrophages, with bacteria-permissive M2 macrophages also detected in deep granulomas. Our histological analysis of Mycobacterium bovis bacillus Calmette-Guerin-elicited granulomas in guinea pigs revealed that S100A9-expressing neutrophils bordered a unique M2 niche within the inner circle of concentrically multilayered granulomas. We evaluated the effect of S100A9 on macrophage M2 polarization based on guinea pig studies. S100A9-deficient mouse neutrophils abrogated M2 polarization, which was critically dependent on COX-2 signaling in neutrophils. Mechanistic evidence suggested that nuclear S100A9 interacts with C/EBPβ, which cooperatively activates the Cox-2 promoter and amplifies prostaglandin E2 production, followed by M2 polarization in proximal macrophages. Because the M2 populations in guinea pig granulomas were abolished via treatment with celecoxib, a selective COX-2 inhibitor, we propose the S100A9/Cox-2 axis as a major pathway driving M2 niche formation in granulomas.

Effectiveness of Endobronchial Ultrasound-Guided Transbronchial Biopsy Combined With Tissue Culture for the Diagnosis of Sputum Smear-Negative Pulmonary Tuberculosis

Background

Microorganisms of tuberculosis (TB) are frequently difficult to identify from the airway specimen; therefore, lung biopsy for further histologic and microbiologic study is required. Endobronchial ultrasound-guided transbronchial biopsy (EBUS-TBB) is used for the diagnosis of pulmonary malignancy, but is rarely in the TB population. The purpose of this study was to verify the effectiveness and safety of EBUS-TBB with histologic study and tissue culture in the diagnosis of sputum smear-negative pulmonary TB.

Methods

Patients who underwent EBUS-TBB with histologic study and TB tissue culture for clinically suspected, but sputum smear-negative pulmonary TB from January 2016 to December 2018, were included. The accuracy of each diagnostic modality was calculated, respectively. Factors that might influence the positive rate of TB culture (washing fluid and tissue specimen) were also evaluated.

Results

One hundred sixty-one patients who underwent EBUS-TBB for clinically suspected, but sputum smear-negative pulmonary TB, were enrolled, and 43 of them were finally diagnosed as having pulmonary TB. The sensitivity of washing fluid (a combination of smear, culture, and polymerase chain reaction for TB) and tissue specimen (a combination of pathology and tissue culture) via EBUS-TBB for TB diagnosis were 48.8 and 55.8%, respectively. The sensitivity for TB diagnosis would be elevated to 67.4% when both washing fluid and tissue specimens are used. The positive TB culture rate would not statistically increase with a combination of tissue specimens and washing fluid. Univariate analysis revealed that TB microorganisms would be more easily cultivated when lesions had an abscess or cavity on the computed tomography (CT) image (presence vs. absence; 62.5 vs. 26.3%, p = 0.022), heterogeneous echogenicity on the EBUS finding (heterogeneous vs. homogeneous; 93.3 vs. 21.4%, p = 0.001), or a necrotic pattern via histologic study (presence vs. absence; 70.6 vs. 30.8%, p = 0.013). Heterogeneous echogenicity in the EBUS finding was the independent predictor according to the results of multivariate analysis. None of our patients encountered major adverse events or received further intensive care after EBUS-TBB.

Conclusion

Endobronchial ultrasound-guided transbronchial biopsy is safe and effective for use in diagnosing sputum smear-negative pulmonary TB. EBUS echoic feature is also a predictor of the positive TB culture rate in pulmonary TB. However, tissue culture via EBUS-TBB has little effect in improving the positive TB culture rate.

Paradoxical development of pleural-based masses in patients with pleural tuberculosis during treatment: a clinical observational study in China

Background

To explored the clinical, pathological, and bacteriological characteristics of pleural-based masses occurred during anti-tuberculosis (TB) treatment in patients with pleural TB.

Methods

Patients referred with newly diagnosed pleural TB were prospectively enrolled into the study. Patients were followed up throughout the treatment, and clinical data were recorded. Percutaneous biopsy and surgical tissues from pleural-based masses were examined histologically and samples sent for PCR. Cytokines in the pleural effusions and clinical factors were collected and compared between different patients.

Results

A total of 122 patients with pleural TB were enrolled, and 34.4% (42/122) displayed newly observed pleural-based mass during the treatment. Twelve cases underwent surgical resection at the 12 ± 0.5 months during the treatment course. Based on the surgical observation, 58.3% (7 /12) were located in pleura, 41.7% (5/12) were located in the lung parenchyma. Pathological observations showed that the pleural-based masses were typed as granulomatous inflammation, fibrous hyperplasia and necrosis. Mycobacterium tuberculosis PCR was positive in 57.1% of the cases (24/42). Any first-line anti-TB drug resistance gene mutations were positive in only 9.5% (4/42). Aside from 12 cases who underwent the surgical operation, 86.7% of the patients (26/30) still had a pleural-based mass at the end of 12 months treatment course. Patients with a pleural-based mass were younger, had a thicker pleural, a higher proportion of pleural adhesive, loculated pleural effusion and residual pleural effusion, and a higher level of LDH, ADA and lower glucose in pleural effusion than those without a pleural-based mass occurrence during the treatment (all Pcorr < 0.05).

Conclusions

Pleural-based masses were observed in about one-third of patients with pleural TB. The masses were in the lung or pleura and were divided into three pathological types.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01910-6.

Rapid Detection and Quantification of Mycobacterium tuberculosis DNA in Paraffinized Samples by Droplet Digital PCR: A Preliminary Study

Background: Rapid and reliable diagnosis of tuberculosis (TB) represents a diagnostic challenge in compartmentalized extrapulmonary TB infection because of the small number of mycobacteria (MTB) and the frequent lack of fresh samples to perform culture. Here, we estimate the performances of homemade droplet digital PCR (ddPCR)-based assays against culture in 89 biopsies, for those fresh and formalin-fixed and paraffin-embedded (FFPE) subsamples were available.

Methods: MTB diagnosis in fresh subsamples was performed by culture. Fresh subsamples were also analyzed for acid-fast bacilli smear-microscopy (AFB) and Xpert^® MTB/RIF (Xpert). MTB examination was repeated in blind in the 89 FFPE subsamples by in-house ddPCR assays targeting the IS6110 and rpoB. Analytical sensitivity of ddPCR assays was evaluated using serial dilution of H37Rv strain. Limit of detection (LOD) was calculated by probit analysis. Results were expressed in copies/10⁶ cells.

Results: IS6110 and rpoB ddPCR assays showed a good linear correlation between expected and observed values (R²: 0.9907 and 0.9743, respectively). Probit analyses predicted a LOD of 17 and 40 copies/10⁶ cells of MTB DNA for IS6110 and rpoB, respectively. Of the 89 biopsies, 68 were culture positive and 21 were culture negative. Considering mycobacterial culture as reference method, IS6110 assay yielded positive results in 67/68 culture-positive samples with a median interquartile range (IQR) of 1,680 (550–8,444) copies/10⁶ cells (sensitivity: 98.5%; accuracy: 98.9). These performances were superior to those reported by the rpoB assay in FFPE subsamples (sensitivity: 66.20%; accuracy: 74.1) and even superior to those reported by Xpert and AFB in fresh subsamples (sensitivity: 79.4 and 33.8%, respectively; accuracy: 84.3 and 49.4, respectively). When Xpert and AFB results were stratified according to mycobacterial load detected by rpoB and IS6110 ddPCR, bacterial load was lower in Xpert and AFB negative with respect to Xpert and AFB-positive samples (p = 0.003 and 0.01 for rpoB and p = 0.01 and 0.11 for IS6110), confirming the poor sensitivity of these methods in paucibacillary disease.

Conclusion: ddPCR provides highly sensitive, accurate, and rapid MTB diagnosis in FFPE samples, as defined by the high concordance between IS6110 assay and culture results. This approach can be safely introduced in clinical routine to accelerate MTB diagnosis mainly when culture results remain unavailable.

Impulse Oscillometry as a measure of airway dysfunction in Sarcoidosis

BACKGROUND

Sarcoidosis is a systemic inflammatory granulomatous disease which commonly affects intrathoracic lymph nodes, lung parenchyma and airways.

OBJECTIVES

To measure respiratory impedance using Impulse Oscillometry (IOS) in patients with pulmonary sarcoidosis and compare the parameters with healthy controls.

METHODS

Patients diagnosed with sarcoidosis (n=28); and age and gender matched healthy controls (n=17) were recruited. Lung volumes and capacities were measured by spirometry and respiratory system impedance was assessed using Impulse Oscillometry System (IOS). Measurements were performed before and 15 minutes after inhalation of a short acting bronchodilator. The IOS and spirometric parameters were compared between two groups and correlated. ROC curve analysis was also performed to identify the IOS parameters which can discriminate between sarcoidosis and healthy controls.

RESULTS

Resistance at 5 and 20 Hz (R5 and R20), small airway resistance (R5-R20), resonant frequency (FRes) and area of reactance (AX) were significantly higher in Sarcoidosis subjects compared with controls. Reactance at 5 and 20 Hz (X5 and X20) were significantly lower in sarcoidosis. FEV1 (% predicted) and FVC (% predicted) were significantly lower in patients with sarcoidosis while FEV1/FVC ratio and peak expiratory flow rate (PEF) values were comparable. Post bronchodilator inhalation, there was improvement in airway resistance and reactance, but no significant changes observed in spirometric parameters. R5, X5 and R5-R20 are promising parameters to discriminate sarcoidosis from healthy controls.

CONCLUSION

Increased airway resistance is a better indicator of airway involvement than airflow limitation by spirometry in pulmonary sarcoidosis.

Non-Infectious Granulomatous Lung Disease: Imaging Findings with Pathologic Correlation

Non-infectious granulomatous lung disease represents a diverse group of disorders characterized by pulmonary opacities associated with granulomatous inflammation, a relatively nonspecific finding commonly encountered by pathologists. Some lesions may present a diagnostic challenge because of nonspecific imaging features; however, recognition of the various imaging manifestations of these disorders in conjunction with patients' clinical history, such as age, symptom onset and duration, immune status, and presence of asthma or cutaneous lesions, is imperative for narrowing the differential diagnosis and determining appropriate management of this rare group of disorders. In this pictorial review, we describe the pathologic findings of various non-infectious granulomatous lung diseases as well as the radiologic features and high-resolution computed tomography imaging features.

Pathology of Granulomatous Pulmonary Diseases

CONTEXT.—

Because granulomas are represented in almost every disease category, the number of clinically and pathologically important granulomatous pulmonary diseases is large. Their diagnosis by pathologists is particularly challenging because of their nonspecificity. A specific diagnosis can be achieved only when a granuloma-inciting agent(s) (eg, acid-fast bacilli, fungi, foreign bodies, etc) are identified microscopically or by culture; this does not occur in most cases. Furthermore, a specific diagnosis cannot be reached in a high percentage of cases. Although sarcoidosis and infectious diseases account for approximately half of pulmonary granulomatous diseases worldwide, there is significant geographic variation in their prevalence.

OBJECTIVES.—

To present updated information to serve as a guide to pathologic diagnosis of pulmonary granulomatous diseases, to address some commonly held misconceptions and to stress the importance of multidisciplinary coordination. Presentation of basic aspects of granulomas is followed by discussion of specific disease entities, such as tuberculous and nontuberculous Mycobacterial infections, fungal, bacterial, and parasitic infections, sarcoidosis, necrotizing sarcoid granulomatosis, berylliosis, hypersensitivity pneumonitis, hot tub lung, rheumatoid nodule, bronchocentric granulomatosis, aspirated, inhaled, and embolized foreign bodies, drug-induced granulomas, chronic granulomatous disease, common variable immunodeficiency, and granulomatous lesions associated with various types of cancer.

DATA SOURCES.—

Review of pertinent medical literature using the PubMed search engine and the author's practical experience.

CONCLUSIONS.—

Although the diagnosis of granulomatous lung diseases continues to present significant challenges to pathologists, the information presented in this review can be helpful in overcoming them. The importance of multidisciplinary coordination in cases where morphologic diagnosis is not possible cannot be overstated.

Pulmonary infarction caused by sarcoidosis vascular involvement: A case report

Sarcoidosis is a systemic granulomatous disease. In pulmonary sarcoidosis, granulomatous vascular involvement is a common feature that occurs in all types of vessels, including large elastic arteries to venules, but sarcoidosis complicated with pulmonary infarction has not been reported. We report a case of a 60 years old female, who was operated on a clinical diagnosis of lung cancer, and histological examination revealed a pulmonary infarction and sarcoidosis. In the pulmonary elastic arteries, granulomas infiltrated the adventitia and media, and caused elastic fiber collapse and destruction. Arterial occlusion by granulomas was observed in the edge of the infarcted area. It was considered that the arterial sarcoidosis granuloma involvement was the cause of pulmonary infarction. Sarcoidosis is a significant risk factor for cardiovascular events. However, pulmonary infarction is an extremely rare complication of sarcoidosis. Our case suggests that sarcoidosis may cause vascular events in the lungs.

Etiological profile and main imaging findings in patients with granulomatous diseases who underwent lung biopsy

Background

Granulomatous Lung Diseases (GLD) encompasses a wide range of infectious and non-infectious conditions characterized by chronic inflammatory response. However, different GLD may share similar imaging findings. In this context, the purpose of this study was to outline the etiological profile and their imaging features in patients with GLD who underwent lung biopsy.

Methods

Patients with granulomatous lesions in lung biopsies and previous chest CT performed from 2014 to 2017 at our institution had imaging data reviewed by three blinded radiologists. The imaging features were analyzed according to the Fleischner Society glossary. Categorical data were represented by absolute (n) and relative (%) frequency. The contingency matrices were analyzed by Pearson's Chi-square test. Interreader agreement was assessed by calculating the intraclass correlation coefficient, using kappa (κ) statistic.

Results

Thirty-eight of 75 (50.7%) patients were women with a mean age of 59 ± 39 years. Infection was the most common cause of GLD (47/75, 62.7%) and Histoplasma capsulatum (27/75, 36%) was the most prevalent etiology. Nodular pattern was the most common imaging feature in histoplasmosis cases (25/27, 92.6%), whereas it occurred in half of cases (24/48) of GLD of other causes (p < 0.05). Among patients with tuberculosis, the second etiology of GLD in our study population, the most common imaging pattern was centrilobular micronodules (3/7, 42.9%), significantly more frequent than in other causes of GLD (6/68, 8.8%). Interreader agreement in detecting imaging features was almost perfect (κ = 0.88-1.00), except the nodular pattern, which had substantial agreement (κ = 0.73).

Conclusions

In our study population, the main etiologies found in patients with granulomatous disease who underwent lung biopsy were fungal or mycobacterial disease, specially histoplasmosis and tuberculosis, and nodular pattern with focal distribution was the most common imaging finding which was detected with substantial interreader agreement.

Tuberculous perihepatic abscess and neurosarcoidosis: report of 2 uncommon manifestations of 2 common granulomatous diseases in 1 patient

Infections caused by pathogens of the Mycobacterium tuberculosis complex, i. e., tuberculosis (TB), and the non-infectious, autoimmune disease sarcoidosis are among the most common granulomatous diseases worldwide. Typically, the lung is the primary site of infection and manifestation, respectively which makes the two diseases important differential diagnoses. Both diseases can affect virtually all organ systems, albeit with significantly lower incidence. CASE PRESENTATION:  We report the case of a 50-year-old Indian man presenting with a tuberculous perihepatic abscess and a systemic inflammatory response after being diagnosed with neurosarcoidosis presenting as a single granuloma in the frontal lobe with lymphadenopathy in 2014. On day of admission the patient presented with right upper abdominal pain and fever for two weeks. With increased inflammatory parameters in serum and after finding of external CT images, a perihepatic abscess was suspected. This encapsulated cave was drained percutaneously under CT control. A high concentration of acid-fast rods was detected using ZN, PCR was positive for M. tuberculosis. Several samples of sputum and urine were microscopically negative but yielded growth of Mycobacteria after four weeks. DISCUSSION:  This is a case presenting with two different granulomatous diseases, each of which manifested itself in an atypical form. The tuberculous liver abscess might either be explained as a flare-up of latent tuberculosis under azathioprine therapy or as a reinfection acquired during one of several visits in the high-prevalence country India. In addition, it must be discussed whether the cerebral granuloma in 2014 could have been an early stage of tuberculous granuloma. Sensitivity of ZN staining is significantly reduced in cerebral samples, and negative PCR-results might be due to low germ load or methodical issues, e. g., decreased sensitivity in formalin fixated samples.

Diagnosis of mediastinal tuberculous lymphadenitis using endobronchial ultrasound-guided transbronchial needle aspiration with rinse fluid polymerase chain reaction

BACKGROUND/PURPOSE

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has been gradually introduced in the diagnosis of mediastinal tuberculous (TB) lymphadenitis. The purposes of this study were to evaluate the utility of polymerase chain reaction for Mycobacterium tuberculosis (TB-PCR) using EBUS-TBNA rinse fluid and to explore the factors that influence the accuracy of EBUS-TBNA.

METHODS

A retrospective study with prospective data collection was carried out with patients with unselected mediastinal lymphadenopathy who underwent EBUS-TBNA and a TB-PCR study from April 2010 to July 2017. Patients without TB were excluded. The diagnostic accuracy rate for each diagnostic modality (pathology, smear, culture, and TB-PCR) was calculated respectively. The characteristics of the lymph node (LN) and the pathologic findings were analyzed as possible impact factors.

RESULTS

240 consecutive patients who received EBUS-TBNA were enrolled, and in the end, 21 patients with a diagnosis of TB lymphadenitis were included. When combined with histologic results and traditional microbiologic studies, the diagnostic accuracy of EBUS-TBNA was 57.1%. If TB-PCR was also utilized, the diagnostic accuracy would significantly increase to 71.4% (p < 0.001). Univariate and multivariate regression analysis revealed that pathology showing necrosis had a higher positive microbiologic result when using EBUS-TBNA rinse fluid.

CONCLUSION

EBUS-TBNA is a valuable tool for diagnosis of mediastinal TB lymphadenitis. Using TB-PCR assay and targeting LNs with a necrotic component would improve the diagnostic performance of EBUS-TBNA.

A case of pulmonary blastomycosis in a common eland (Taurotragus oryx)

This case report describes for the first time pulmonary blastomycosis in a captive common eland (Taurotragus oryx). The animal has been in captivity for over 14 years and the clinical signs observed before death were non-specific. The carcass was examined grossly and histologically using special stains. There were yellowish, firm and gritty nodules of varying sizes (0.5–2 cm in diameter) on the pleura, in the lung, mediastinal lymph nodes and pericardium. The nodules showed pyogranulomatous inflammation and broad based budding yeast (PAS, Giemsa positive and ZN negative) consistent with Blastomyces dermatitidis. Regular screening of soil and environment including animals in captivity should be encouraged to avert possible spread of the mold in favourable conditions. Public awareness should be improved on fungal diseases.

GeneXpert MTB/RIF for rapid diagnosis and rifampin resistance detection of endobronchial tuberculosis

BACKGROUND AND OBJECTIVE

Delayed diagnosis and treatment of tuberculosis (TB) contribute to poor outcomes, especially for endobronchial TB (EBTB), which typically leads to tracheobronchial stenosis. Finding rapid and accurate diagnostic tools for EBTB is crucial. GeneXpert Mycobacterium tuberculosis (MTB)/rifampin (RIF) was recommended by the World Health Organization (WHO) as a standard molecular biological diagnostic technique for MTB. The aim of this study was to evaluate the efficacy of GeneXpert MTB/RIF for diagnosing EBTB and for evaluating RIF resistance.

METHODS

Biopsy tissue and bronchial brushings from EBTB patients were prospectively assessed with GeneXpert MTB/RIF. The diagnostic yields of auramine O-stained sputum smears and bronchial brush smears were obtained, and the results were compared with the cultures of sputum and biopsy tissues for MTB.

RESULTS

In 61 confirmed cases of EBTB, the sensitivities of sputum smear, bronchial brush smear, sputum culture and tissue culture to diagnose EBTB were 13.1%, 32.8%, 36.1% and 68.9%, respectively. For bronchial brushings and biopsies, our data showed sensitivities of 57.4% and 63.9%, respectively, and a specificity of 100% for GeneXpert MTB/RIF, and these results were superior to those of sputum smears, bronchial brush smears and sputum culture. GeneXpert MTB/RIF for bronchial brushings and biopsies showed complementarity in its diagnostic performance. Resistance to RIF was identified in 17.4% (8/46) of GeneXpert MTB-positive cases.

CONCLUSION

GeneXpert MTB/RIF may enable more rapid EBTB diagnosis and determination of RIF resistance, which are crucial for timely treatment.

Infectious Diseases

Pulmonary infections are caused by a wide range of pathogenic microorganisms, including bacteria, viruses, fungi, and parasites. The most common lung infections in immunocompetent hosts are caused by pyogenic bacteria (e.g., Streptococcus pneumoniae), common respiratory viruses, and mycoplasma. These infections are usually diagnosed by clinical and microbiologic studies, including cultures and serology tests. Lung biopsy is rarely used in these diagnoses. Patients with life-threatening pneumonia, especially those who are immunocompromised, are more likely to undergo lung biopsy to rule out unusual infections not easily diagnosed using conventional microbiologic methods and for which treatment strategies may be different. Pathogens more likely to be diagnosed using lung biopsy for which there are characteristic pathologic changes are highlighted in this chapter and listed in Table 4.1.

Necrotizing sarcoid granulomatosis: A distinctive form of pulmonary granulomatous disease

OBJECTIVES

To define the characteristics of necrotizing sarcoid granulomatosis (NGS) a very rare pulmonary disease hardly recognised by pulmonologists and pathologists.

DATA SOURCE

PubMed was searched for the term necrotising or necrotizing sarcoid granulomatosis.

STUDY SELECTION

All cases reported in the English literature were included.

RESULTS

NGS is presented at all ages (range 8-68 years) with a median age of 42 years old. It shows female (62%) and Caucasian (80%) predominance. The most frequent symptoms are cough, fever, dyspnoea and chest pain. Extra-pulmonary involvement is found in one third of the cases, with ocular being the most common (12.5%). At imaging, multiple nodules (64.75%) or a solitary mass (20.49%) are found accompanied by mediastinal lymphadenopathy at one third of the cases. It can be clinically mistaken for malignancy as it is tumour-like, increases rapidly in size and it is hyperfixating in PET-SCAN. Histologically, NGS is defined by large areas of necrosis, well-formed granulomas and vascularitis.

CONCLUSION

NGS is a disease often confounded clinically with malignancy or with sarcoidosis even histologically when all criteria are not strictly applied. This review provides NGS' characteristics and discusses its differential diagnosis form sarcoidosis, Wegener granulomatosis and tuberculosis.

Adverse Drug Reactions in the Intensive Care Unit

Adverse drug reactions (ADRs) are undesirable effects of medications used in normal doses [1]. ADRs can occur during treatment in an intensive care unit (ICU) or result in ICU admissions. A meta-analysis of 4139 studies suggests the incidence of ADRs among hospitalized patients is 17% [2]. Because of underreporting and misdiagnosis, the incidence of ADRs may be much higher and has been reported to be as high as 36% [3]. Critically ill patients are at especially high risk because of medical complexity, numerous high-alert medications, complex and often challenging drug dosing and medication regimens, and opportunity for error related to the distractions of the ICU environment [4]. Table 1 summarizes the ADRs included in this chapter.

Neutrophils and the S100A9 protein critically regulate granuloma formation

Macrophages have the potential to undergo cellular transformation into epithelioid cells, and their concentric accumulation in tissues results in the development of granulomas. Although epithelioid cells are an essential and dominant component of granulomas, other cell types have also been detected, which may contribute to the establishment of well-organized granulomas, as observed in human granulomatous diseases. We herein demonstrated that neutrophils may mediate these functions. By taking advantage of the guinea pig pulmonary granuloma model, we obtained a rat monoclonal antibody with unique reactivity to granuloma cells. This antibody, termed G213, reacted with clusters of neutrophils located in the central area of granulomas, and a biochemical analysis identified the G213-reactive antigen as S100A9, a calcium-binding protein of the S100 family, which was expressed abundantly in neutrophils. Consistent with the multifaceted functions attributed to S100A9, including its role in neutrophil extravasation and macrophage activation, the blockade of S100A9 functions with the specific inhibitor, tasquinimod, impaired the formation of organized granulomas with neutrophil cores. These results demonstrate the critical role of neutrophils and the S100A9 protein in granuloma formation. Because intragranuloma S100A9⁺ neutrophils were also detected in humans, these results indicate the potential of tasquinimod, a new anticancer drug candidate, for manipulating human granulomatous diseases.

Utility of endobronchial ultrasound-guided transbronchial needle aspiration in diagnosing non-specific inflammatory intrathorcacic lymphadenitis

BACKGROUND AND OBJECTIVE

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has emerged as a minimally invasive technique for diagnosing intrathoracic malignancies and some benignancies; however, there are no data available on the utility of EBUS-TBNA for the diagnosis of non-specific inflammatory intrathoracic lymphadenitis.

METHODS

A prospective analysis was performed from 104 patients with enlarged lymphadenopathy suspected of non-specific lymphadenitis referred for EBUS-TBNA between October 2009 and March 2012. Rapid on-site cytological evaluation was not adopted. Microbiological tests were carried out in all patients. Patients were excluded from the study if there was other diagnosis being defined.

RESULTS

One hundred ninety-one lesions were aspirated in 94 patients with enlarged mediastinal/hilar lymph nodes within reach of EBUS-TBNA, which were diagnosed as non-specific intrathorcacic lymphadenitis by pathology and clinical follow-up. According to EBUS-TBNA pathologies, 94 patients were categorized into four kinds: (i) inflammatory cell infiltrates and/or noncaseating necrosis in 38 cases; (ii) granuloma formed by epithelioid cells and/or fiber hyperplasia in 13 cases; (iii) lymph node tissue/lymphocyte without obvious abnormal lesions in 41 cases; (iv) inadequate sample in 2 cases. Bacterial and/or fungal smears and cultures were carried out in all 94 patients (100%), with pathogens being found in 4 (4.3%) cases. All patients (100%) underwent acid-fast staining and culture for mycobacterium tuberculosis to exclude tuberculosis. No procedure-related complication was observed.

CONCLUSIONS

EBUS-TBNA can provide pathological and microbiological evidences for diagnosing non-specific inflammatory intrathoracic lymphadenopathy, and it is a safe and effective first-line investigation for ruling out malignancies and other benign diseases.

A Histomorphological Pattern Analysis of Pulmonary Tuberculosis in Lung Autopsy and Surgically Resected Specimens

Background. Tuberculosis (TB) is a major cause of morbidity and mortality globally. Many cases are diagnosed on autopsy and a subset of patients may require surgical intervention either due to the complication or sequelae of TB. Materials and Methods. 40 cases of resected lung specimens following surgery or autopsy in which a diagnosis of pulmonary tuberculosis was made were included. Histopathological pattern analysis of pulmonary tuberculosis along with associated nonneoplastic changes and identification of Mycobacterium tuberculosis bacilli was done. Results. The mean age of diagnosis was 41 years with male predominance (92.5%). Tuberculosis was suspected in only 12.1% of cases before death. Seven cases were operated upon due to associated complications or suspicion of malignancy. Tubercular consolidation was the most frequent pattern followed by miliary tuberculosis. The presence of necrotizing granulomas was seen in 33 cases (82.5%). Acid fast bacilli were seen in 57.5% cases on Ziehl-Neelsen stain. Conclusion. Histopathology remains one of the most important methods for diagnosing tuberculosis, especially in TB prevalent areas. It should be considered in the differential diagnosis of all respiratory diseases because of its varied clinical presentations and manifestations.

Transbronchial lung biopsy with a flexible cryoprobe: First case report from India

Sarcoidosis and tuberculosis are granulomatous disorders that mimic each other both clinically and radiologically. Both can present with fever and pulmonary nodules and often require the performance of transbronchial lung biopsy (TBLB) for diagnosis. In recent studies, the flexible cryoprobe for carrying out TBLB has been found to be useful in the diagnosis of disorders diffusely involving the lung parenchyma. Here, we present the case of a 29-year-old man who presented with fever and cough and was found to have multiple small nodules in both lungs. TBLB with a flexible cryoprobe helped in differentiating between sarcoidosis and tuberculosis.

Giant Cell Lesions of Lungs: A Histopathological and Morphometric Study of Seven Autopsy Cases

INTRODUCTION

Macrophages undergo fusion to form multinucleated giant cells (MGC) in several pathologic conditions. The exact mechanism of their generation is still unclear. MGC are a common feature of granulomas that develop during various inflammatory reactions.

AIM

To study the histopathological features of giant cell lesions in lungs and correlate the characteristics of giant cells with other histopathological findings. Also, to determine the utility of morphometry to differentiate foreign body and Langhans MGC.

MATERIALS AND METHODS

Seven cases were analysed. Specimen of lungs was grossed, sectioned and processed. Routinely, tissue sections were stained by Haematoxylin and Eosin (H&E) stain. Polarizing microscopy and special stains were employed in selected cases. Granulomas and MGC were counted and measured. Several other parameters like location, distribution, type and number of MGC, associated predominant inflammatory component and nature of granulomas were analysed.

RESULTS

Five patterns of lesions were observed in seven cases. Aspiration pneumonia was seen in three cases (42.85%) and constituted the most common pattern. However, aspiration pneumonia as the only cause of MGC was seen in only one case (14.28%). Pulmonary tuberculosis and asteroid bodies constituted two cases (28.57%) each. Cryptococcal pneumonia and cholesterol clefts constituted one case (14.28%) each. Crypococci were demonstrated to be positively birefringent by polarized microscopy on Ziehl-Neelsen stained sections. Based on statistical analysis of morphometric data, a new index (NP index) was proposed to statistically categorize MGC into foreign body type and Langhans type. NP index value of ≤0.016 was found to be statistically significant (p<0.005) in foreign body MGC. It had high sensitivity and efficacy.

CONCLUSION

MGC may not be always associated with granulomas. The mechanisms that lead to the occurrence of MGC, independent of granuloma needs to be elucidated. Morphometry may serve as a useful aid. But a pathologist has to rely on the morphological details to categorize MGC.

Utility of endobronchial ultrasound-guided-fine-needle aspiration and additional value of cell block in the diagnosis of mediastinal granulomatous lymphadenopathy

Background:

Endobronchial ultrasound-guided transbronchial fine-needle aspiration is a minimally invasive technique for diagnosis of mediastinal lesions. Although most studies have reported the utility of EBUS-FNA in malignancy, its use has been extended to the benign conditions as well.

Objective:

To evaluate the diagnostic yield and cytologic accuracy of endobronchial ultrasound-guided transbronchial fine-needle aspiration (EBUS-FNA) in cases of clinically and radiologically suspected granulomatous diseases.

Patients and Method:

From May 2010 to April 2015, 43 of 115 patients who underwent EBUS-FNA at one center for radiologically and clinically suspicious granulomatous lesions, and with no definite histological diagnosis, were included in this retrospective study.

Results:

When the histological diagnosis was taken as the gold standard, the sensitivity of EBUS-FNA was 85% and specificity was 100% with the positive predictive value of 100. The combined diagnostic sensitivity of EBUS-FNA and transbronchial lung biopsy was 100%. In 4 cases, cell block provided an exclusive morphological diagnosis of sarcoidosis which was noncontributory by EBUS-FNA.

Conclusion:

Our study supports the use of EBUS-FNA, by virtue of being a safe, minimally invasive, and an outpatient procedure, in the diagnosis of granulomatous mediastinal lymphadenopathy, thereby obviating more invasive testing in a significant number of patients. Also, cell block provides additional data in the diagnosis in these benign mediastinal diseases.

Paracoccidioidomycosis Mimicking Sarcoidosis: A Review of 8 Cases

Sarcoidosis is a multisystem disorder that is characterized by noncaseous epithelioid cell granulomas, which may affect almost any organ. Thoracic involvement is common and accounts for most of the morbidity and mortality associated with this disease. The diagnosis is based on exhaustive exclusion of differential diagnoses, particularly granulomatous infections. We report data on eight patients with paracoccidioidomycosis mimicking sarcoidosis. Five patients presented with a chronic pulmonary type infection and three had a disseminated form after immunosuppressive treatment. The mycological diagnosis in noncaseating granulomas is emphasized and reviewed.

Lymphadenopathy and fever in a chef during a stay in Europe

This case illustrates a rare presentation (as lymphadenopathy and fever) of one of the most common zoonotic diseases worldwide--brucellosis--in a 22-year-old Brazilian male (a chef) who had recently returned to Brazil after having lived in and traveled around Europe for one year. The histopathology, clinical history, and response to treatment were all consistent with a diagnosis of brucellosis, which was confirmed by PCR in a urine sample. We also review some aspects of brucellosis, such as the clinical features, diagnosis, and management.

Incidence and aetiologies of pulmonary granulomatous inflammation: a decade of experience

BACKGROUND AND OBJECTIVE

Granulomatous lung disease (GLD) is caused by a wide range of conditions. Often there is a need to correlate pathological findings with clinical, microbiological or radiological data to determine an aetiology. The aim of this study was to determine the different aetiologies of GLD over the past decade.

METHODS

Among 2228 consecutive lung specimens from 1999 to 2011, 226 cases (10.1%) were positive for GLD. One hundred ninety patients were retrospectively reviewed and diagnoses were assigned based on availability of histological/clinical/microbiological correlation.

RESULTS

A confident, probable and uncertain diagnosis was made in 68.4%, 13.2% and 18.4% patients. The aetiologies comprised infectious, non-infectious and uncertain in 54.7%, 26.8% and 18.4% patients. Mycobacterial infections constituted 27% of all patients, and included atypical, tuberculous and unclassified mycobacteria in order of frequency. Acid-fast bacilli (AFB) were visualized in tissue sections in 29% cases and cultured in 73% cases. Fungal infections comprised 27% of all cases, which included Coccidioides, Cryptococcus, Aspergillus and Histoplasma in order of frequency. Fungi were visualized in tissue sections with Gomori methenamine silver (GMS) stain in 83% patients and cultured in 52% cases. Sarcoidosis was the major non-infectious aetiology, constituting 21% of all patients. Necrosis in granulomas was associated with the presence of infection (P < 0.001).

CONCLUSIONS

The aetiology in necrotizing GLD with negative AFB and GMS stains is most likely infectious due to atypical mycobacteria. Coccidioidomycosis was the most common fungal infection. The aetiology in non-necrotizing GLD is most likely non-infectious, probably sarcoidosis.

Performance characteristics of nested polymerase chain reaction vs real-time polymerase chain reaction methods for detecting Mycobacterium tuberculosis complex in paraffin-embedded human tissues

OBJECTIVES

Nucleic acid amplification tests on formalin-fixed, paraffin-embedded (FFPE) tissue specimens enable Mycobacterium tuberculosis complex (MTB) detection and rapid tuberculosis diagnosis in the absence of microbiologic culture tests. We aimed to evaluate the efficacy of different polymerase chain reaction (PCR) methods for detecting Mycobacterium species in FFPE tissues.

METHODS

We examined 110 FFPE specimens (56 nonmycobacterial cases, 32 MTB, and 22 nontuberculous mycobacteria [NTM] determined by acid-fast bacilli [AFB] culture) to assess five PCR methods: nested PCR (N-PCR) (Seeplex MTB Nested ACE Detection; Seegene, Seoul, South Korea), an in-house real-time PCR (RT-PCR) method, and three commercial RT-PCR methods (AccuPower MTB RT-PCR [Bioneer, Seoul, Korea], artus M tuberculosis TM PCR [Qiagen, Hilden, Germany], and AdvanSure tuberculosis/NTM RT-PCR [LG Life Sciences, Seoul, Korea]).

RESULTS

The results of N-PCR, in-house RT-PCR, and AdvanSure RT-PCR correlated well with AFB culture results (concordance rates, 94.3%, 87.5%, and 89.5%, respectively). The sensitivity of N-PCR (87.5%) was higher than that of the RT-PCR methods, although these differences were not statistically significant between N-PCR and the in-house and AdvanSure RT-PCR methods (68.8% and 80.0%, respectively). All the PCR methods had high specificities, ranging from 98.2% to 100%. Only two NTM cases were detected by AdvanSure RT-PCR, implying a very low sensitivity.

CONCLUSIONS

Well-designed RT-PCR and N-PCR can effectively identify MTB in FFPE specimens.

Pulmonary fibrosis in sarcoidosis. Clinical features and outcomes

Sarcoidosis is a systemic inflammatory disease with a predilection for the respiratory system. Although most patients enter remission and have good long-term outcomes, up to 20% develop fibrotic lung disease, whereby granulomatous inflammation evolves to pulmonary fibrosis. There are several radiographic patterns of pulmonary fibrosis in sarcoidosis; bronchial distortion is common, and other patterns, including honeycombing, are variably observed. The development of pulmonary fibrosis is associated with significant morbidity and can be fatal. Dyspnea, cough, and hypoxemia are frequent clinical manifestations. Pulmonary function testing often demonstrates restriction from parenchymal involvement, although airflow obstruction from airway-centric fibrosis is also recognized. Complications of fibrotic pulmonary sarcoidosis include pulmonary hypertension from capillary obliteration and chronic aspergillus disease, with hemoptysis a common and potentially life-threatening manifestation. Immunosuppression is not always indicated in end-stage sarcoidosis. Lung transplantation should be considered for patients with severe fibrotic pulmonary sarcoidosis, as mortality is high in these patients.

Over-expression of thymosin β4 in granulomatous lung tissue with active pulmonary tuberculosis

Recent studies have shown that thymosin β4 (Tβ4) stimulates angiogenesis by inducing vascular endothelial growth factor (VEGF) expression and stabilizing hypoxia inducible factor-1α (HIF-1α) protein. Pulmonary tuberculosis (TB), a type of granulomatous disease, is accompanied by intense angiogenesis and VEGF levels have been reported to be elevated in serum or tissue inflamed by pulmonary tuberculosis. We investigated the expression of Tβ4 in granulomatous lung tissues at various stages of active pulmonary tuberculosis, and we also examined the expression patterns of VEGF and HIF-1α to compare their Tβ4 expression patterns in patients' tissues and in the tissue microarray of TB patients. Tβ4 was highly expressed in both granulomas and surrounding lymphocytes in nascent granulomatous lung tissue, but was expressed only surrounding tissues of necrotic or caseous necrotic regions. The expression pattern of HIF-1α was similar to that of Tβ4. VEGF was expressed in both granulomas and blood vessels surrounding granulomas. The expression pattern of VEGF co-localized with CD31 (platelet endothelial cell adhesion molecule, PECAM-1), a blood endothelial cell marker, and partially co-localized with Tβ4. However, the expression of Tβ4 did not co-localize with alveolar macrophages. Stained alveolar macrophages were present surrounding regions of granuloma highly expressing Tβ4. We also analyzed mRNA expression in the sputum of 10 normal and 19 pulmonary TB patients. Expression of Tβ4 was significantly higher in patients with pulmonary tuberculosis than in normal controls. These data suggest that Tβ4 is highly expressed in granulomatous lung tissue with active pulmonary TB and is associated with HIF-1α- and VEGF-mediated inflammation and angiogenesis. Furthermore, the expression of Tβ4 in the sputum of pulmonary tuberculosis patients can be used as a potential marker for diagnosis.

Endobronchial ultrasound-guided transbronchial needle aspiration in diagnosing intrathoracic tuberculosis

BACKGROUND

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a minimally invasive procedure that has enabled mediastinal and hilar lymph node assessment with a high sensitivity, but its role in the diagnosis of intrathoracic tuberculosis (TB) has not been established.

METHODS

We prospectively studied 59 patients suspected of having TB with thoracic lymph node lesions or intrapulmonary lesions accessible by EBUS-TBNA at a clinical center for thoracic medicine from January 2010 to December 2011. Bronchoscopic findings, EBUS-TBNA procedures, pathologic findings, and microbiologic results were recorded.

RESULTS

Of 59 eligible patients, 41 patients had TB, 5 had lung cancer, 7 had inflammation, and 6 had sarcoidosis. Sensitivity was 85%, specificity was 100%, positive and negative predictive values were 100% and 75%, respectively, and accuracy was 90% by EBUS-TBNA for TB. Pathologic findings were consistent with TB in 80% of patients (33 of 41), and in 27% (11 of 41) the smear was positive. A total of 37 patients with TB had cultures, of whom 17 (46%) were positive. There were 80 mediastinal and hilar lymph nodes and 5 intrapulmonary lesions that were biopsied in the 41 patients with TB. Multivariate logistic regression revealed that short-axis diameter was an independent risk factor associated with positive pathology, smear, and culture (p < 0.05). Additionally, pathology showing necrosis was an independent risk factor associated with a positive culture.

CONCLUSIONS

Endobronchial ultrasound-guided transbronchial needle aspiration has a high diagnostic yield in the investigation of suspected intrathoracic TB by means of aspiration of intrathoracic lymph nodes and tracheobronchial wall-adjacent lung lesions.

Histoplasmosis presenting with multiple pulmonary nodules. A case mimicking radiological features of pulmonary metastasis

We present a case of histoplasmosis with multiple pulmonary nodules in a patient with a history of melanoma. This case closely simulated malignancy, including the presence of feeding vessel sign, which occurs in pulmonary metastasis. We emphasize the need to be aware of this infection in areas where histoplasmosis is endemic.

Microenvironments in tuberculous granulomas are delineated by distinct populations of macrophage subsets and expression of nitric oxide synthase and arginase isoforms

Macrophages in granulomas are both antimycobacterial effector and host cell for Mycobacterium tuberculosis, yet basic aspects of macrophage diversity and function within the complex structures of granulomas remain poorly understood. To address this, we examined myeloid cell phenotypes and expression of enzymes correlated with host defense in macaque and human granulomas. Macaque granulomas had upregulated inducible and endothelial NO synthase (iNOS and eNOS) and arginase (Arg1 and Arg2) expression and enzyme activity compared with nongranulomatous tissue. Immunohistochemical analysis indicated macrophages adjacent to uninvolved normal tissue were more likely to express CD163, whereas epithelioid macrophages in regions where bacteria reside strongly expressed CD11c, CD68, and HAM56. Calprotectin-positive neutrophils were abundant in regions adjacent to caseum. iNOS, eNOS, Arg1, and Arg2 proteins were identified in macrophages and localized similarly in granulomas across species, with greater eNOS expression and ratio of iNOS/Arg1 expression in epithelioid macrophages as compared with cells in the lymphocyte cuff. iNOS, Arg1, and Arg2 expression in neutrophils was also identified. The combination of phenotypic and functional markers support that macrophages with anti-inflammatory phenotypes localized to outer regions of granulomas, whereas the inner regions were more likely to contain macrophages with proinflammatory, presumably bactericidal, phenotypes. Together, these data support the concept that granulomas have organized microenvironments that balance antimicrobial anti-inflammatory responses to limit pathology in the lungs.

Histopathologic approach to the surgical lung biopsy in interstitial lung disease

Interpretation of lung biopsy specimens is an integral part in the diagnosis of interstitial lung disease (ILD). The process of evaluating a surgical lung biopsy for disease involves answering several questions. Unlike much of surgical pathology of neoplastic lung disease, arriving at the correct diagnosis in nonneoplastic lung disease often requires correlation with clinical and radiologic findings. The topic of ILD or diffuse infiltrative lung disease covers several hundred entities. This article is meant to be a launching point in the clinician's approach to the histologic evaluation of lung disease.

The linkage of innate and adaptive immune response during granulomatous development

Granulomas represent a spectrum of inflammatory sequestration responses that may be initiated by a variety of agents, including non-infectious environmental factors and infectious microbial pathogens. Although this reaction is designed to be protective, the associated tissue injury is often responsible for a profound degree of pathology. While many of the mechanisms that sustain the development of the granuloma are enigmatic, it is accepted that the maintenance of this inflammatory process is dependent upon dynamic interactions between an inciting agent, inflammatory mediators, various immune and inflammatory cells, and structural cells of the involved tissue. The best studied of the host-dependent processes during granuloma development is the innate and adaptive immune response. The innate immune response by antigen-presenting cells [APCs; dendritic cells (DCs) and macrophages] is initiated quickly to protect from overwhelming pathogens, but with time, can also activate the adaptive immune response. APCs, essential regulators of the innate immune response, can respond to microbial ligands through Toll-like receptors (TLRs), which function in the recognition of microbial components and play an important role to link the innate and adaptive immune responses. CD4(+) T helper (Th) cells are essential regulators of adaptive immune responses and inflammatory diseases. Recently, the Notch system has been shown to be an important bridge between APCs and T cell communication circuits. In the present review, we discuss recent findings that explore the mechanisms in the linkage of innate and adaptive immunity, including granulomatous formation though TLRs and Notch activation.

Chickenpox-related pulmonary granulomas in immunocompetent adults: clinicopathologic and molecular features of an underrated occurrence

Pulmonary granulomas represent a common inflammatory reaction to several lung infective or noninfective diseases. However, little is known about the histology and clinical presentation of chickenpox-related granulomas in immunocompetent subjects. We collected a series of 8 adult patients (mean age, 40 y; range, 33 to 53 y) with several bilateral pulmonary granulomas incidentally discovered after imaging studies. All patients were asymptomatic and had experienced a varicella-zoster virus (VZV) infection as adults but were clinically suspected to have a metastatic neoplasm of unknown origin. Chest computed tomography scan revealed numerous, tiny (few millimeters to 1 cm in size) nodules randomly dispersed through the lungs. Positron emission tomography scan performed in 4 patients was negative. All patients underwent video-assisted thoracoscopic surgical resection and were still alive and well. At histology, granulomas consisted of well-defined, rounded, small nodules centered by a deeply eosinophilic, acellular necrosis rimmed by lamellar dense collagen and a chronic inflammatory infiltrate with or without multinucleated giant cells. Chickenpox-related granulomas were included in the differential diagnosis along with several other granulomatous diseases. Polymerase chain reaction-based molecular analysis for VZV performed on paraffin sections detected VZV DNA in all 8 cases. By contrast, 85 cases of pulmonary granulomas of different etiologies were simultaneously studied by molecular analysis with negative results. Pathologists should be familiar with the peculiar morphologic appearance of chickenpox-related granulomas. A careful search for a history of VZV infection in adulthood and molecular studies may be very helpful in confirming the diagnosis.

Necrotizing sarcoid granulomatosis of the lung in a 12-year-old boy with an atypical clinical course

Necrotizing sarcoid granulomatosis (NSG) is a disorder of unknown etiology, rarely described in childhood, belonging to the heterogeneous group of the pulmonary angiitis and granulomatosis. One of the characteristics of NSG is to have typically a benign clinical course with minimal treatment with systemic steroids or even with no therapy at all. Here, we report the case of a boy with a lung consolidation, with morphological and histological features consistent with a diagnosis of NSG. Good clinical and roentgenographic response to high dose prednisone treatment was followed three times by relapses, when steroid treatment was tapered. New lesions were detected in different areas of the lung and not in initially affected area, never previously described in NSG and only rarely in other pulmonary angiitides.

Pathogenesis of sarcoidosis

Sarcoidosis is a systemic granulomatous disorder of unknown origin. Recent research uncovered underlying immunological and genetic mechanisms, which will pave the way for more effective pharmaceutical studies. At present some of this knowledge is clinically exploited to monitor therapy and expected genetic progress will allow the development of prognostic genetic patterns or molecular signatures. Moreover, it has become obvious that several etiologic agents and cofactors will exist. These will be of animate and inanimate nature and their interplay with host mechanisms discussed in this review determines disease phenotypes.