Molecular Diagnosis of Tubercular Lymphadenopathy from Fine-Needle Aspirates in Pediatric Patients

The diagnosis of peripheral tubercular lymphadenopathy (TBLN) in pediatric patients is often a challenge because features evident on fine-needle aspiration cytology (FNAC) or tissue biopsy can be deceptive for the reason that they result from an immunological response. This study aimed to evaluate polymerase chain reaction (PCR) for Mycobacterium tuberculosis complex (MTBC) in pediatric patients under clinical suspicion for TBLN and to assess its role in the evaluation of cases cytodiagnosed as reactive lymphoid hyperplasia.

This was a cross-sectional study conducted on 45 pediatric patients clinically suspected and unsuspected for TBLN. FNAC, culture on Löwenstein-Jensen medium, and real-time PCR were performed. Comparative values with reference to the culture were calculated.

Cytology had a sensitivity and specificity of 38.5 and 87.5%, respectively. Real-time PCR had a sensitivity and specificity of 84.6 and 81.3%, respectively. Of the 32 cases with a cytodiagnosis of reactive lymphoid hyperplasia, 53% were positive both on PCR and culture for M. tuberculosis; the φ value of 0.93 demonstrated a strong association between these 2 methods.

Real-time PCR is useful in detecting MTBC in pediatric patients, and it also helps in the diagnosis of cases missed on FNAC.