Abstract:

Objective: To evaluate the value of acid-fast staining, routine pathology microscopy (short“pathology microscopy”), and TB-DNA in diagnosis of superficial lymph node tuberculosis, to seek the optimal diagnostic method of superficial lymph node tuberculosis. Methods: A retrospective study was conducted. Following the inclusion criteria, we collected basic information, biopsy methods, and acid-fast staining, pathology microscopy, TB-DNA of pathological tissues, and other data from 114 patients who underwent lymph node biopsy due to superficial lymph node enlargement at Chongqing Public Health Medical Center from January to September 2022, and were followed up in the outpatient department for more than 3 months (1 lymph node biopsy was taken from each patient). The diagnostic efficiency of different methods was compared based on the final clinical diagnosis as a reference standard. Results: Among 114 patients with lymphadenopathy, the positive rate of TB-DNA examination in pathological tissue (80.7% (92/114)) was higher than that of acid-fast staining (2.6% (3/114)) with significant difference (χ²=142.935, P=0.000), lower than that of pathology microscopy (91.2% (104/114)) with significant difference (χ²=5.235, P=0.022). The positive rate of combined pathology microscopy (98.2% (112/114)) was significantly higher than that of TB-DNA and pathology microscopy, and the difference was statistically significant (χ²=18.627, P=0.000; χ²=5.630, P=0.018). Finally, 104 patients were finally diagnosed as lymph node tuberculosis, and 10 patients were diagnosed as non tuberculous lesions. Among 104 patients with lymph node tuberculosis, 36 (34.6%) patients did not receive anti-tuberculosis treatment before admission, and 68 (65.4%) patients received anti-tuberculosis treatment outside the hospital, the positive rates of pathology microscopy were 88.9% (32/36) and 95.6% (65/68) with no significant difference (χ²=0.785, P=0.376), and the positive rates of TB-DNA were 80.6% (29/36) and 91.2% (62/68)(χ²=1.554, P=0.213). The positive rates of pathology microscopy in 79 (76.0%) patients who underwent ultrasound-guided biopsy and 25 (24.0%) patients who underwent surgical resection of the rates of lesion biopsy were 96.2% (76/79) and 84.0% (21/25)(χ²=2.770, P=0.096), of TB-DNA were 89.9% (71/79) and 80.0% (20/25), respectively, with no statistically significant differences (χ²=0.910, P=0.340). Using the final clinical diagnosis as the reference standard, the sensitivity of acid-fast staining, pathology microscopy, and TB-DNA were 2.9% (3/104), 93.3% (97/104), and 87.5% (91/104), the specificity were 100.0% (10/10), 30.0% (3/10), and 90.0% (9/10), the accuracy were 11.4% (13/114), 87.7% (100/114), and 80.7% (92/114), and the Kappa values were 0.005, 0.233, and 0.502. Conclusion: Superficial lymph node tuberculosis is mainly cervical lymph node tuberculosis, and is more common in middle-aged and young people. The positive rate of acid-fast staining is extremely low, and pathology microscopy and TB-DNA have higher diagnostic efficacy. Combining two examination methods can improve diagnostic performance. Although lymph node biopsy is equally effective in diagnosing general superficial lymph nodes as surgical lesion biopsy, considering factors such as cost and trauma, lymph node biopsy can be the first choice.

Key words: Tuberculosis, lymph node, Clinical laboratory techniques, Diagnosis, Evaluation studies