Tree-in-Bud Pattern of Pulmonary Tuberculosis on Thin-Section CT: Pathological Implications

Impact of vitamin C deficiency on imaging patterns and ventilatory function in pulmonary tuberculosis

Background

Studies have shown that vitamin C is essential for the immune response to tuberculosis (TB), and that its deficiency may elevate the risk of TB and related complications. This prospective study investigated the association between disease severity, imaging findings and vitamin C levels.

Methods

This study enrolled 109 patients with confirmed pulmonary tuberculosis based on Mycobacterium tuberculosis culture. Patients were divided into two groups based on serum vitamin C levels: 59 patients (54.13%) with normal levels and 50 (45.87%) with low levels.

Results

At baseline, patients in the low vitamin C group showed significantly higher bacillar loads, with 86.00% presenting loads of 2+ or higher compared with 59.32% in the normal group (p < 0.001). After 2 months of treatment, 83.05% of the normal vitamin C group achieved culture conversion, while only 28.00% of the low vitamin C group reached the same milestone (p < 0.001). CT imaging at baseline revealed that the low vitamin C group had a significantly higher mean frequency of the tree-in-bud pattern (2.66 vs. 2.05; p < 0.001). Cavitary lesions were more prevalent in the low vitamin C group, in the superior right lobe (0.34 vs. 0.13; p = 0.011) and superior left lobe (0.34 vs. 0.14; p = 0.012). After 6 months of treatment, the low vitamin C group exhibited a higher prevalence of bronchiectasis (mean involvement in both lungs: 0.58 vs. 0.16; p < 0.001), cavitary lesions (0.32 vs. 0.00; p = 0.002), and fibrosis (0.90 vs. 0.36; p < 0.001). Pulmonary function tests showed greater impairment in the low vitamin C group. The forced expiratory volume decreased by 5.77% compared to 3.59% in the normal group (p < 0.001), the forced vital capacity (FVC) decreased by 12.00% vs. 6.67% (p < 0.001), and the Tiffeneau index by 3.34 vs. 2.13 (p = 0.002). Receiver operating characteristic (ROC) analysis indicated that FVC (AUC = 0.826) and forced expiratory flow (AUC = 0.745) were stronger predictors of treatment success in patients with normal vitamin C levels.

Conclusion

Vitamin C deficiency is correlated with increased disease severity, delayed bacterial clearance, and persistent pulmonary damage in patients with tuberculosis. Vitamin C supplementation can enhance treatment outcomes in tuberculosis therapy.

Prediction of active drug-resistant pulmonary tuberculosis based on CT radiomics: construction and validation of independent models and combined models for residual pulmonary parenchyma

Background

Drug-resistant tuberculosis (DR-TB) is a severe public health threat and burden worldwide. This study seeks to develop and validate both independent and combined radiomic models using pulmonary cavity (PC), tree-in-bud sign (TIB), total lung lesions (TLL), and residual pulmonary parenchyma (RPP) to evaluate their effectiveness in predicting DR-TB.

Methods

We recruited 306 confirmed active pulmonary tuberculosis cases from two hospitals, comprising 142 drug-resistant and 164 drug-sensitive cases. Patients were assigned to five training and testing cohorts: PC (n = 109, 47), TIB (n = 214, 92), TLL (n = 214, 92), RPP (n = 214, 92), and their combination (n = 109, 47). Radiomic features were extracted using variance thresholding, K-best, and LASSO techniques. We developed four separate radiomic models with random forest (RF) for DR-TB prediction and created a combined model integrating all features from the four indicators. Model performance was validated using ROC curves.

Results

We extracted 10, 2, 10, 3, and 9 radiomic features from PC, TIB, TLL, RPP, and the combined model, respectively. The combined model achieved AUC values of 0.886 (95% CI: 0.827-0.945) in the training set and 0.865 (95% CI: 0.764-0.966) in the testing set. It slightly surpassed the PC model in the training set (0.886 vs. 0.850, p < 0.05) and was comparable in the testing set (0.865 vs. 0.850, p > 0.05). The combined model showed similar performance to the TIB, TLL, and RPP models in both sets (p > 0.05).

Conclusion

The newly defined and developed RPP model and the combined model demonstrated robust performance in identifying DR-TB, highlighting the potential of CT-based radiomic models as effective non-invasive tools for DR-TB prediction.

Post tuberculosis lung disease and tuberculosis sequelae: A narrative review

Post Tuberculosis lung disease (PTLD) and post tuberculosis sequelae is a global and poorly recognized problem, amplified by social factors and immunocompromising conditions, inadequate treatment, lack of effective prevention of tuberculosis (TB) infection and disease. As a disease, it remained until recently poorly defined, with studies heterogenous with regards to regions, population demographics, risk factors, cohort sizes, and methods. Pathophysiologically, even successfully treated pulmonary TB disease has sequelae i.e. involving central and peripheral airways, lung parenchyma and pleura, resulting in airway narrowing and dilatation, fibrocavitation and emphysema, pulmonary vascular changes as well as pleural fibrosis. Functionally patients have airflow limitation, restrictive disease or a mixture of both not rarely associated with respiratory, or even ventilatory failure. Quality of life is often impaired through disability, TB relapse, superinfections and through increased susceptibility to reinfection and persistent inflammation, leading to progressive lung function decline and an increased risk of cardiovascular disease and cancer. Premature mortality due to PTLD is very likely, but poorly described.

Comparative analysis of airway invasive aspergillosis and endobronchial spread of tuberculosis on high resolution computed tomography

The presence of tree-in-bud (T-I-B) pulmonary opacities on high resolution computed tomography (HRCT) in tuberculosis endemic areas is frequently regarded as a sine qua non for endobronchial tuberculosis (TB). That is not always the case, however. They can also be found in immunocompromised non-neutropenic patients with airway invasive aspergillosis (IA). Understanding the differences between the two conditions is thus critical for making an accurate diagnosis. This research aims to pinpoint those distinguishing characteristics. The study defines the distribution and morphology of T-I-B opacities and other ancillary pulmonary findings in the two conditions by performing a retrospective analysis of HRCT features in 53 immunocompromised patients with lower respiratory tract symptoms, 38 of whom were positive for TB on BAL fluid analysis and 15 confirmed IA by Galactomannan method. While the global distribution of T-I-B opacities affecting all lobes favoured TB (p=0.002), the basal distribution overwhelmingly favoured IA (p<0.0001). Morphologically, dense nodules with discrete margins were associated with TB, whereas nodules with ground-glass density and fuzzy margins were associated with IA. Clustering of nodules was observed in 18 TB patients (p=0.0008). Cavitation was found in 14 (36.84%) of TB patients but not in any of the IA patients. Peri-bronchial consolidation was found in seven (46.67%) of the IA cases and four (10.53%) of the TB cases (p=0.005, 0.007). The presence of ground-glass opacity and bronchiectasis did not differ significantly between the two groups. Not all T-I-B opacities on HRCT chest in immunocompromised patients in endemic TB areas should be reported as tubercular. Immunocompromised non-neutropenic patients with airway IA can be identified earlier with tree-in-bud opacities on HRCT chest, even in the absence of a nodule with halo, resulting in earlier and more effective management.

CT and 18F-FDG PET abnormalities in contacts with recent tuberculosis infections but negative chest X-ray

Close contacts of individuals with pulmonary tuberculosis are at risk for tuberculosis infection and the development of active tuberculosis. In current contact investigations, immunologic tests (the tuberculin skin test and interferon-gamma release assay) and chest X-ray examinations are used to dichotomize contacts with Mycobacterium tuberculosis infections into those with active (X-ray abnormalities) versus latent tuberculosis (normal radiographs). This article is a critical review of computed tomographic (CT) and 18-fluorodeoxyglucose positron emission tomographic (PET) findings of incipient tuberculosis without X-ray abnormalities based on a systematic literature review of twenty-five publications. The CT and 18-fluorodeoxyglucose PET studies revealed minimal pauci-nodular infiltrations in the lung parenchyma and mediastinal lymph nodes abnormalities with metabolic uptake in approximately one-third of asymptomatic close contacts with negative chest radiographic and bacteriological/molecular results for active tuberculosis. Tuberculosis with minimal changes challenge the validity of simply dichotomizing cases of recent M. tuberculosis infections in contacts depending on the presence of X-ray abnormalities as the recent infections may spontaneously regress, remain stagnant, or progress to active tuberculosis in human and nonhuman primate studies. Whether contacts with tuberculosis with minimal changes are interpreted as having active tuberculosis or latent tuberculosis has clinical implications in terms of specific benefits and harms under the current contact management. Advanced imaging tools may help further stratify contacts intensely exposed to M. tuberculosis on a continuous spectrum from latent tuberculosis to incipient, subclinical and active tuberculosis. Identifying incipient tuberculosis would provide an opportunity for earlier and tailored treatment before active tuberculosis is established.

Latent tuberculosis reactivation in the setting of SARS-Cov-2 infection: The analysis of the radiologic features that help the diagnosis

In Italy tuberculosis is a relatively rare disease and people coming from developing nations are usually affected. The radiological findings are variable and depend on the tuberculosis activity, if primary or post-primary. In literature, few data are reported about the co-existence of COVID-19 and lung tuberculosis. In this case report, authors describe the imaging features of latent lung tuberculosis in a patient with SARS-CoV-2 disease. The important role of CT imaging in identifying and diagnosing other infectious lung diseases presenting in the setting of the polymorphism and severity of SARS-CoV-2 disease is also discussed.

Early Lesion of Post-Primary Tuberculosis: Subclinical Driver of Disease and Target for Vaccines and Host-Directed Therapies

The characteristic lesion of primary tuberculosis is the granuloma as is widely studied in human tissues and animal models. Post-primary tuberculosis is different. It develops only in human lungs and begins as a prolonged subclinical obstructive lobular pneumonia that slowly accumulates mycobacterial antigens and host lipids in alveolar macrophages with nearby highly sensitized T cells. After several months, the lesions undergo necrosis to produce a mass of caseous pneumonia large enough to fragment and be coughed out to produce a cavity or be retained as the focus of a post-primary granuloma. Bacteria grow massively on the cavity wall where they can be coughed out to infect new people. Here we extend these findings with the demonstration of secreted mycobacterial antigens, but not acid fast bacilli (AFB) of M. tuberculosis in the cytoplasm of ciliated bronchiolar epithelium and alveolar pneumocytes in association with elements of the programmed death ligand 1 (PD-L1), cyclo-oxygenase (COX)-2, and fatty acid synthase (FAS) pathways in the early lesion. This suggests that M. tuberculosis uses its secreted antigens to coordinate prolonged subclinical development of the early lesions in preparation for a necrotizing reaction sufficient to produce a cavity, post-primary granulomas, and fibrocaseous disease.

A case of tuberculosis of the rare azygos lobe of the right lung

Background

The azygos lobe is a rare anatomical variant seen in the upper lobe of right lung. It occurs during embryological development due to the failure of posterior cardinal vein to migrate supero-medially. It is often an incidental finding on imaging and is asymptomatic in majority of cases. Tuberculosis involving the azygos lobe is extremely rare. Only a few cases of tuberculosis involving the azygos lobe have been reported in literature.

Case presentation

We present a rare case report of tuberculosis infection involving the azygos lobe in a 57-year-old male with history of chronic cough, fever, hemoptysis, and weight loss.

Conclusions

The azygos lobe is usually asymptomatic, but it may be misdiagnosed as bulla, lung cyst, or abscess. In rare cases it may be associated with certain pathology such as tuberculosis, other infections, and lung cancer. Hence, it is pertinent for a radiologist to be aware of this variant when reporting chest imaging cases.

A Case Report of Renal Tuberculosis With Associated Unusual Pulmonary Findings

Tuberculosis (TB) is a wide-reaching chronic inflammatory disease predominantly infecting the lungs. When it infects other sites, it is termed extrapulmonary TB. Among the extrapulmonary forms, genitourinary TB (GU-TB) accounts for 30%-40% of cases. We report a case of pulmonary-renal TB with unusual pulmonary findings. Subsequent investigation of a frank haematuria case revealed positive Mycobacterium TB culture and acid-fast bacillus polymerase chain reaction (AFB-PCR) samples of urine, with abdominal imaging findings suggestive of GU-TB. Pulmonary involvement was evident on chest imaging as bilateral innumerable small nodules and tree-in-bud pattern with negative AFB-PCR from bronchoalveolar lavage samples. Clinicians practicing in endemic countries should adopt a high index of suspicion to avoid treatment delays and the development of complications of GU-TB.

Clinical and radiological variants of lung damage in the infection caused by staphylococcus aureus

Despite the high level of modern technologies in the field of laboratory methods and imaging of the respiratory system, the problem of early and accurate differential diagnosis of inflammatory lung diseases remains important in practical medicine. It leads to improved treatment results and a reduction in the number of complications (pleural empyema, fistulas, mediastinitis, sepsis, etc.), and in some cases allows suspecting the presence of a primary purulent source in the body, such as that in the case of septic pulmonary embolism. The review covers the Staphylococcus aureus specifics as a pathogen of lung diseases, relevant epidemiology, pathogenesis, clinical features and imaging diagnostics of various types of inflammatory changes in the lungs with a focus on destruction.

Micro-Computed Tomography Analysis of the Human Tuberculous Lung Reveals Remarkable Heterogeneity in Three-dimensional Granuloma Morphology

Rationale: Our current understanding of tuberculosis (TB) pathophysiology is limited by a reliance on animal models, the paucity of human TB lung tissue, and traditional histopathological analysis, a destructive two-dimensional approach that provides limited spatial insight. Determining the three-dimensional (3D) structure of the necrotic granuloma, a characteristic feature of TB, will more accurately inform preventive TB strategies.Objectives: To ascertain the 3D shape of the human tuberculous granuloma and its spatial relationship with airways and vasculature within large lung tissues.Methods: We characterized the 3D microanatomical environment of human tuberculous lungs by using micro computed tomography, histopathology, and immunohistochemistry. By using 3D segmentation software, we accurately reconstructed TB granulomas, vasculature, and airways in three dimensions and confirmed our findings by using histopathology and immunohistochemistry.Measurements and Main Results: We observed marked heterogeneity in the morphology, volume, and number of TB granulomas in human lung sections. Unlike depictions of granulomas as simple spherical structures, human necrotic granulomas exhibit complex, cylindrical, branched morphologies that are connected to the airways and shaped by the bronchi. The use of 3D imaging of human TB lung sections provides unanticipated insight into the spatial organization of TB granulomas in relation to the airways and vasculature.Conclusions: Our findings highlight the likelihood that a single, structurally complex lesion could be mistakenly viewed as multiple independent lesions when evaluated in two dimensions. In addition, the lack of vascularization within obstructed bronchi establishes a paradigm for antimycobacterial drug tolerance. Lastly, our results suggest that bronchogenic spread of Mycobacterium tuberculosis reseeds the lung.

COVID-19 and pulmonary tuberculosis - A diagnostic dilemma

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Meanwhile, pulmonary tuberculosis(TB) is one of the most common infective lung diseases in developing nations. The concurrence of pulmonary TB and COVID-19 can lead to poor prognosis, owing to the pre-existing lung damage caused by TB. Case presentation: We describe the imaging findings in 3 cases of COVID-19 pneumonia with co-existing pulmonary TB on HRCT thorax. The concurrence of COVID-19 and pulmonary TB can be a diagnostic dilemma. Correct diagnosis and prompt management is imperative to reduce mortality and morbidity. Hence it is pertinent for imaging departments to identify and report these distinct entities when presenting in conjunction.

Discriminating Small-Sized (2 cm or Less), Noncalcified, Solitary Pulmonary Tuberculoma and Solid Lung Adenocarcinoma in Tuberculosis-Endemic Areas

Background. Pulmonary tuberculoma can mimic lung malignancy and thereby pose a diagnostic dilemma to clinicians. The purpose of this study was to establish an accurate, convenient, and clinically practical model for distinguishing small-sized, noncalcified, solitary pulmonary tuberculoma from solid lung adenocarcinoma. Methods. Thirty-one patients with noncalcified, solitary tuberculoma and 30 patients with solid adenocarcinoma were enrolled. Clinical characteristics and CT morphological features of lesions were compared between the two groups. Multivariate logistic regression analyses were applied to identify independent predictors of pulmonary tuberculoma and lung adenocarcinoma. Receiver operating characteristic (ROC) analysis was performed to investigate the discriminating efficacy. Results. The mean age of patients with tuberculoma and adenocarcinoma was 46.8 ± 12.3 years (range, 28–64) and 61.1 ± 9.9 years (range, 41–77), respectively. No significant differences were observed concerning smoking history and smoking index, underlying disease, or tumor markers between the two groups. Univariate and multivariate analyses showed age and lobulation combined with pleural indentation demonstrated excellent discrimination. The sensitivity, specificity, accuracy, and the area under the ROC curve were 87.1%, 93.3%, 90.2%, and 0.956 (95% confidence interval (CI), 0.901–1.000), respectively. Conclusion. The combination of clinical characteristics and CT morphological features can be used to distinguish noncalcified, solitary tuberculoma from solid adenocarcinoma with high diagnostic performance and has a clinical application value.

Study of the association of interferon-γ gene polymorphisms and Th1/Th2 balance in tuberculosis susceptibility

OBJECTIVES

This study investigated and analyzed the association of interferon-γ (IFN-γ) gene polymorphisms and Th1/Th2 balance in tuberculosis susceptibility.

METHODS

From January 2018 to January 2020, 121 tuberculosis patients that were hospitalized for initial treatment and were chosen as the pulmonary tuberculosis group, and another 80 healthy individuals with physical examination in the same period were selected as the control group. The genetic distribution of IFN-γ +874 sites in the two sets of subjects was detected by sequence-specific primer PCR (PCR-SSP), the serum IFN-γ level was detected by ELISA, and the ratio of Th1 and Th2 on cells in two sets of subjects were detected by flow cytometry. Subsequently, we compared the differences in IFN-γ degree and the changes in Th1/Th2 in patients with different genotypes.

RESULTS

The difference in the distribution of IFN-γ (+874 T/A) genotype frequencies between the two groups of subjects was significantly different (P<0.05), and the frequency of A allele in the tuberculosis group was clearly higher than that in the control group (P<0.05). Compared with the control group, the Th1 cells percentage in the pulmonary tuberculosis group decreased remarkably, the Th2 cells percentage increased significantly, while the Th1/Th2 ratio was notably decreased (P<0.05). In addition, the Th1/Th2 ratio in tuberculosis patients with an IFN-γ (+874 T/A) genotype AA was remarkably lower than those with AT+TT genotype (P<0.05).

CONCLUSION

An AA genotype with IFN-γ (+874 T/A) is a susceptible genotype for tuberculosis. The mechanism may be related to the imbalance of Th1/Th2 which is more likely to occur in patients with AA genotype. This can lead to a decline in immune function of the body, making it more susceptible to infection with mycobacterium which induces tuberculosis.

Low pectoralis muscle index, cavitary nodule or mass and segmental to lobar consolidation as predictors of primary multidrug-resistant tuberculosis: A comparison with primary drug sensitive tuberculosis

Background

The loss of muscle mass in primary multidrug-resistant tuberculosis (MDR-TB) has not been examined in previous studies. This study aimed to investigate that low pectoralis muscle index and characteristic CT features can help differentiate patients with primary MDR-TB from those with drug-sensitive tuberculosis (DS-TB).

Material and methods

From 2010 to 2016, we retrospectively enrolled 90 patients with primary MDR-TB and 90 age- and sex-matched patients with primary DS-TB. The pectoralis muscle mass was quantitatively measured on axial CT images using density histogram analysis. The pectoralis muscle index (PMI) was defined as the pectoralis muscle mass divided by body mass index. We compared the PMI and characteristic CT features of pulmonary tuberculosis between the two groups.

Results

Low PMI, segmental to lobar consolidation, cavity in consolidation, cavitary nodule or mass, and bilateral involvement were more frequently observed in patients with MDR-TB than in those with DS-TB. In stepwise multivariate logistic regression analysis, low PMI (odds ratio, 2.776; 95% confidence interval, 1.450–5.314; p = 0.002), segmental or lobar consolidation (odds ratio, 3.123; 95% confidence interval, 1.629–5.987; p = 0.001), and cavitary nodule or mass (odds ratio, 2.790; 95% confidence interval, 1.348–5.176; p = 0.002) were significant factors for MDR-TB.

Conclusion

Low pectoralis muscle index, segmental to lobar consolidation and cavitary nodule or mass can help differentiate primary MDR-TB from DS-TB.

The Pathogenesis of Tuberculosis-The Koch Phenomenon Reinstated

Research on the pathogenesis of tuberculosis (TB) has been hamstrung for half a century by the paradigm that granulomas are the hallmark of active disease. Human TB, in fact, produces two types of granulomas, neither of which is involved in the development of adult type or post-primary TB. This disease begins as the early lesion; a prolonged subclinical stockpiling of secreted mycobacterial antigens in foamy alveolar macrophages and nearby highly sensitized T cells in preparation for a massive necrotizing hypersensitivity reaction, the Koch Phenomenon, that produces caseous pneumonia that is either coughed out to form cavities or retained to become the focus of post-primary granulomas and fibrocaseous disease. Post-primary TB progresses if the antigens are continuously released and regresses when they are depleted. This revised paradigm is supported by nearly 200 years of research and suggests new approaches and animal models to investigate long standing mysteries of human TB and vaccines that inhibit the early lesion to finally end its transmission.

Delayed Isolation of Active Pulmonary Tuberculosis in Hospitalized Patients: A Pivotal Role of Radiologic Evaluation

OBJECTIVE. The purpose of this study was to determine factors related to delayed isolation of patients hospitalized with active pulmonary tuberculosis (TB). MATERIALS AND METHODS. A total of 130 immunocompetent hospitalized patients with active pulmonary TB who had positive sputum culture results from January 2015 to December 2017 were reviewed. Delayed isolation of pulmonary TB was defined as failure to initiate airborne isolation within the first 3 days of hospitalization. Clinical and microbiologic characteristics of the patients and radiologic features on chest radiography (n = 130) and chest CT (n = 118) were retrospectively reviewed. Findings were compared between patients with early isolation and those with delayed isolation. Univariate and multivariate analyses were performed to determine independent predictors of delayed isolation. RESULTS. Forty-four patients (34%) had delayed isolation after initial hospitalization. On univariate and multivariate analyses, atypical presentation of active pulmonary TB on CT (odds ratio, 7.203; 95% CI, 2.203-23.551; p = 0.001) and concurrent lung parenchymal diseases on CT (odds ratio, 14.605; 95% CI, 3.274-65.155; p < 0.001) were significant predictors of delayed isolation of patients with active pulmonary TB. CONCLUSION. Awareness of the factors related to delayed diagnosis of active pulmonary TB is important to avoid an unexpected in-hospital outbreak of TB and control the disease. Atypical presentation of active pulmonary TB and concurrent lung parenchymal diseases on CT are significant factors related to delayed isolation of hospitalized patients with active pulmonary TB.

Clustered micronodules as predominant manifestation on CT: A sign of active but indolently evolving pulmonary tuberculosis

OBJECTIVE

To investigate the prevalence, patient characteristics, and natural history of clustered micronodules (CMs) in active pulmonary tuberculosis.

MATERIALS AND METHODS

From January 2013 through July 2018, 833 consecutive patients with bacteriologically or polymerase chain reaction-proven active pulmonary tuberculosis were retrospectively evaluated. CMs were defined as a localized aggregation of multiple dense discrete micronodules, which primarily distributed around small airways distal to the level of the segmental bronchus: small airways surrounded by CMs maintained luminal patency and the CMs might coalesce into a larger nodule. The patients were dichotomized according to whether the predominant computed tomography (CT) abnormalities were CMs. We analyzed radiologic and pathologic findings in patients whose predominant diagnostic CT abnormalities were CMs, along with those of incidental pre-diagnostic CT scans, if available. Chi-square, McNemar, Student t-test and Wilcoxon-signed rank test were performed.

RESULTS

CMs were the predominant CT abnormality in 2.6% of the patients (22/833, 95% CI, 1.8-4.0%) with less sputum smear-positivity (4.8% vs 31.0%; p = .010) and a similar proportion of immunocompromised status (40.9% vs 46.0%; p = .637) than those without having CMs as the predominant CT abnormality. The time interval for minimal radiologic progression was 6.4 months. The extent of CMs increased with disease progression, frequently accompanied by consolidation and small airway wall thickening. Pathologically, smaller CMs were non-caseating granulomas confined to the peribronchiolar interstitium, whereas larger CMs were caseating granulomas involving lung parenchyma. Two of the five patients with a pre-diagnostic CT scan obtained more than 50 months pre-diagnosis showed an incipient stage of CMs, in which they were small peribronchiolar nodules.

CONCLUSION

Active pulmonary tuberculosis manifested predominantly as CMs in 2.6% of patients, with scarce of acid-fast bacilli smear-positivity and no association with impaired host immunity. CMs indolently progressed, accompanied by consolidation and small airway wall thickening, and originated from small nodules.