Diagnostic yield of endoscopic ultrasound-guided fine-needle aspiration of tubercular lymphadenitis using combination of cytology and Gene Xpert Mycobacterium tuberculosis/rifampicin (MTB/RIF) genes

Construction and Validation of a Predictive Model for Culture Results of Mycobacterium Tuberculosis in Superficial Lymph Nodes

Background

To establish and validate a nomogram for predicting the culture results of Mycobacterium tuberculosis in superficial lymph nodes.

Methods

The clinical data of patients with superficial lymph node tuberculosis admitted to Xi'an City Chest Hospital from November 23, 2018, to May 30, 2024, were selected and divided into a training set and a validation set according to a ratio of 7:3. Influencing factors were identified through multivariate logistic regression analyses. Using R version 4.3.2, we developed a predictive model and generated a nomogram based on this model. The performance of the nomogram was evaluated using receiver operating characteristic (ROC) curves, calibration curve analysis (CCA), and decision curve analysis (DCA).

Results

The positive rate of superficial lymph node tuberculosis culture was 23.0% (103/446). Multivariate Logistic regression analysis showed that anti-tuberculosis treatment duration (OR=0.98, 95% CI: 0.97 ~ 0.99), initial treatment or retreatment (OR=0.12, 95% CI: 0.05 ~ 0.28), and adenosine deaminase (OR=1.12, 95% CI: 1.03 ~ 1.22) were independent factors affecting the culture results of Mycobacterium tuberculosis in superficial lymph nodes. The areas under the ROC curves were 0.86 (95% CI: 0.82-0.91) for the training set and 0.89 (95% CI: 0.84-0.95) for the validation set. The P values of calibration curves were 1.000 and 0.961, respectively, and the predicted values were in good agreement with the actual values. The threshold probabilities of clinical decision curves were 3%~64% and 1%~68%, respectively.

Conclusion

The positive rate of Mycobacterium tuberculosis culture in superficial lymph nodes is low. The increase in retreatment patients and anti-tuberculosis treatment time are obstacle factors for Mycobacterium tuberculosis culture positivity, while an increase in adenosine deaminase is a promoting factor for Mycobacterium tuberculosis culture positivity. The nomogram model established based on these factors can be used to predict the results of Mycobacterium tuberculosis culture in superficial lymph nodes.

Current role of endoscopic ultrasound for gastrointestinal and abdominal tuberculosis

A high incidence of tuberculosis (TB), especially in endemic countries, makes this infectious disease a concern. Abdominal TB contributes to 10% of extrapulmonary TB. Due to nonspecific clinical, radiological, and endoscopic findings, diagnosing abdominal TB continues to be a challenge. Hence, a precise diagnosis is needed. The diagnosis of gastrointestinal disease using endoscopic ultrasound (EUS) is often performed due to its high resolution and ability to provide a real-time visual representation of the gastrointestinal tract and extramural structures. EUS-guided fine-needle aspiration (FNA) and fine-needle biopsy (FNB) have helped diagnose TB as they offer an adequate specimen for cytology or histopathological examination. This method is considered safer, more effective, and more efficient. The capacity of EUS to diagnose abdominal TB based on the affected organs was examined via a literature search. We reviewed the role of EUS in diagnosing esophageal, gastric, pancreatic, peripancreatic, hepatosplenic, peritoneal, and intestinal TB. Generally, EUS aids in diagnosing abdominal TB. In some organs, it is superior to other diagnostic modalities. However, further examinations, such as cytology or histopathology and microbial, are still needed. We also studied the roles of EUS-FNA and EUS-FNB. EUS-FNA has shown a high diagnostic yield in esophageal (94.3-100%), pancreatic and peripancreatic (76.2%), and intestinal TB (84.1%). As minimally invasive methods, EUS-FNA and EUS-FNB can successfully provide sufficient samples. EUS is a functional diagnostic modality for abdominal TB. EUS-FNA and EUS-FNB provide sufficient samples safely and efficiently for further cytology, histopathology, and microbial examinations.

Disseminated tuberculosis mimicking abdominal metastatic carcinoma: A case report

RATIONALE

Extra-pulmonary tuberculosis (TB) has long been a diagnostic challenge for clinicians, often requiring extensive workup and invasive procedures, with the risk of significant complications. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is a minimally invasive and highly accurate diagnostic modality for the evaluation of mediastinal and abdominal lymphadenopathy and masses. Several reports on the utility of EUS-FNA as a favorable method for diagnosing extrapulmonary TB have been published.

PATIENT CONCERNS

A 54-year-old man complained of intermittent melena.

DIAGNOSES

18 fluorine-fluorodeoxyglucose positron emission tomography/computed tomography revealed suspected carcinoma metastasis. EUS-FNA did not reveal any evidence of malignancy.

INTERVENTIONS AND OUTCOMES

Laparoscopy was performed, and frozen section pathology during surgery showed granulomas with focal necrosis. Mycobacterium tuberculosis polymerase chain reaction was positive, but acid-fast bacilli staining was negative. Anti-TB treatment was initiated, and the patient was advised to visit the local TB dispensary regularly.

LESSONS

The presence of atypical inflammation of inadequate material or non-representative samples of extra-pulmonary TB was observed on EUS-FNA cytology. Mycobacterium tuberculosis polymerase chain reaction and acid fast bacilli should be performed to diagnose TB because of its higher sensitivity.