Outcome of untreated lung nodules with histological but no microbiological evidence of tuberculosis

Predictive factors for tuberculous peripheral pulmonary lesions during radial endobronchial ultrasound

BACKGROUND

Tuberculosis frequently poses diagnostic challenge when it presents as a peripheral pulmonary lesion (TB-PPL). The growing use of radial endobronchial ultrasound (rEBUS) for PPL biopsy highlights the need to identify predictive factors for TB-PPL, which is crucial for procedure safety.

METHODS

A six-year retrospective review at our institution on adult patients with TB and malignant-PPL diagnosed from rEBUS procedure from October 1, 2016, to December 31, 2022. Clinical, radiological, procedural, histological and microbiological data were extracted and analysed.

RESULTS

387 PPLs were included in our cohort, 32 % were TB-PPL and 68 % were malignant-PPL. The median age was 63 (IQR 55-70) years, with the TB-PPL group significantly younger. The median size of the target lesion was 2.90 (IQR 2.26-4.00) cm. The overall rEBUS diagnostic yield was 85.3 %, with a 1.3 % pneumothorax risk. Multivariate analysis identified independent predictors for TB-PPL, including age <60 years (adj OR 2.635), target lesion size <2 cm (adj OR 2.385), upper lobe location (adj OR 2.020), presence of a cavity on pre-procedural CT (adj OR 4.186), and presence of rEBUS bronchogram (adj OR 2.722). These variables achieved an area under the curve of 0.729 (95 % CI 0.673-0.795) with a diagnostic accuracy of 75.49 % (95 % CI 70.68-79.88).

CONCLUSIONS

Despite non-specific radiological findings in TB-PPL, our study identifies younger age, target lesion size less than 2 cm, upper lobe location, the presence of cavitation, and rEBUS bronchogram were independent clinical predictors for TB-PPL. This prediction model potentially helps mitigate the risk of accidental TB exposure during bronchoscopic procedures. A future prospective cohort study to validate these findings is essential to allow proper triaging of patient planning for rEBUS procedure.

Subsequent Antituberculous Treatment May Not Be Mandatory Among Surgically Resected Culture-Negative Pulmonary Granulomas: A Retrospective Nationwide Multicenter Cohort Study

Background

Histologic diagnosis of granuloma is often considered clinically equivalent to a definite diagnosis of pulmonary tuberculosis (TB) in endemic areas. Optimal management of surgically resected granulomatous inflammation in lung with negative mycobacterial culture results, however, remains unclear.

Methods

From 7 medical institutions in northern, middle, and southern Taiwan between January 2010 and December 2018, patients whose surgically resected pulmonary nodule(s) had histological features suggestive of TB but negative microbiological study results and who received no subsequent anti-TB treatment were identified retrospectively. All patients were followed up for 2 years until death or active TB disease was diagnosed.

Results

A total of 116 patients were enrolled during the study period. Among them, 61 patients (52.6%) were clinically asymptomatic, and 36 (31.0%) patients were immunocompromised. Solitary pulmonary nodule accounted for 44 (39.6%) of all cases. The lung nodules were removed by wedge resection in 95 (81.9%), lobectomy in 17 (14.7%), and segmentectomy in 4 (3.4%) patients. The most common histological feature was granulomatous inflammation (n=116 [100%]), followed by caseous necrosis (n=39 [33.6%]). During follow-up (218.4 patient-years), none of the patients developed active TB.

Conclusions

In patients with surgically resected culture-negative pulmonary granulomas, the incidence rate of subsequent active TB is low. Watchful monitoring along with regular clinical, radiological, and microbiological follow-up, instead of routine anti-TB treatment, may also be a reasonable option.

[Overview: granulomatous diseases of the lung]

The spectrum of pulmonary granulomatoses is wide and includes infectious and noninfectious entities, each with very different therapeutic consequences. The first step of histological examination discriminates between necrotizing and non-necrotizing granulomatosis. After this, an infectious cause of the granulomatosis has to be excluded by special histological stains and molecular-pathologic methods, if necessary. Diagnosis also includes clinical, radiological, and microbiological findings. The process of pathological examination should be standardized as described.

Surgical resection is sufficient for incidentally discovered solitary pulmonary nodule caused by nontuberculous mycobacteria in asymptomatic patients

Incidentally discovered solitary pulmonary nodules (SPN) caused by nontuberculous mycobacteria (NTM) is uncommon, and its optimal treatment strategy remains uncertain. This cohort study determined the clinical characteristics and outcome of asymptomatic patients with NTM-SPN after surgical resection. Resected SPNs with culture-positive for NTM in six hospitals in Taiwan during January, 2010 to January, 2017 were identified. Asymptomatic patients without a history of NTM-pulmonary disease (PD) or same NTM species isolated from the respiratory samples were selected. All were followed until May 1, 2019. A total of 43 patients with NTM-SPN were enrolled. Mycobacterium avium complex (60%) and M. kansasii (19%) were the most common species. The mean age was 61.7 ± 13.4. Of them, 60% were female and 4% had history of pulmonary tuberculosis. The NTM-SPN was removed by wedge resection in 38 (88%), lobectomy in 3 (7%) and segmentectomy in 2 (5%). Caseating granuloma was the most common histologic feature (58%), while chronic inflammation accounts for 23%. Mean duration of the follow-up was 5.2 ± 2.8 years (median: 4.2 years [2.5–7.0]), there were no mycobacteriology recurrence or NTM-PD development. In conclusion, surgical resection is likely to curative for incidentally discovered NTM-SPN in asymptomatic patients without culture evidence of the same NTM species from respiratory specimens, and routine mycobacterium culture for resected SPN might be necessary for differentiating pulmonary tuberculosis and NTM because further treatment differs.

Recommendations for lung cancer screening in Southern Africa

Lung cancer remains the leading cause of cancer-related deaths in southern Africa. Early trials of chest radiograph-based screening in males at high risk for lung cancer found no mortality benefit of a radiograph alone, or a radiograph plus sputum cytology screening strategy. Large prospective studies, including the National Lung Screening Trial, have shown an all-cause mortality benefit when low-dose computed tomography (LDCT) was used as a screening modality in patients that are at high risk of developing lung cancer. The South African Thoracic Society, based on these findings, and those from several international guidelines, recommend that annual LDCT should be offered to patients between 55-74 years of age who are current or former smokers (having quit within the preceding 15 years), with at least a 30-pack year smoking history and with no history of lung cancer. Patients should be in general good health, fit for surgery, and willing to undergo further investigations if deemed necessary. Given the high local prevalence of tuberculosis (TB) infection and post-TB lung disease, which can radiographically mimic lung cancer, a conservative threshold (nodule size ≥6 mm) should be used to determine whether the baseline LDCT screen is positive (thus nodules <6 mm require no action until the next annual screen). If a non-calcified, solid or partly solid nodule is ≥6 mm, but <10 mm with no malignant features (e.g., distinct spiculated margins), the LDCT should be repeated in 6 months. If a solid nodule or the largest component of a non-solid nodule is ≥10 or ≥6 mm and enlarging or with additional malignant features present, definitive action to exclude lung cancer is warranted. Patients should be screened annually until 15 years have elapsed from date of smoking cessation, they turn 80, become unfit for a curative operation or significant changes are observed.