Characteristics of remnant lymph nodes after 6 months standard chemotherapy in cervical tuberculous lymphadenitis

Background: Cervical tuberculous lymphadenitis (CTBL) is common extrapulmonary tuberculosis. The response of CTBL to therapy may be slow or paradoxical, with frequent development of enlarging or remnant lymph nodes (LNs) during and after effective treatment. The computered tomography (CT) shows distinguish features is useful to diagnosis of CTBL. We investigated the incidence and microbiological responses of patients who had still remnant LNs on CT scan 6 months (Ms) after anti-TB chemotherapy.

Methods: Medical records of HIV-negative patients aged ≥18 years with CTBL between July 2009 and December 2015 were analyzed. Patients treated with daily 6 Ms of isoniazid, rifampin and ethambutol plus pyrazinamide for the first 2 Ms were included. After 6 Ms treatment, CT scan was taken to evaluate remnant LNs. Remnant LNs sized ≥10 ㎜ with central necrosis, peripheral rim enhancement, or perinodal infiltration on CT scan underwent fine needle aspiration/biopsy (FNA).

Results: A total of 159 patients with definite or probable CTBL had completed treatment during the study period. Twenty-six patients were excluded due to loss or ongoing follow-up. Of 133 patients were enrolled, 109 patients (81 female; mean age, 42.9 years) were taken CT scan 6 Ms after treatment. Among the 109 study patients, 34 (31.2%) patients had remnant LNs on CT scan. Remnant LNs were more common significantly on male (38.2% [13/34] vs 20% [15/75], p<0.01). Age of patients with remnant LN was significantly lower (mean years ±standard deviation, 36±14.6 vs. 46.1±16.4, p<0.01) compared to completely resolved patients. FNA taken on 12 patients revealed granuloma in 2/6 (30%). AFB and TB PCR were positive in 3/12 (25%), 8/11 (72.7%), respectively. However none of 12 samples were positive in Tb culture. There was no significant difference in treatment duration between FNA taken or not (median Ms [Interquartile range], 8 [1.8] vs 10.5 [3], p=0.16). None of patients with FNA taken had relapse during median 10.5 Ms follow-up. But one of patients without FNA had enlarged LN 2 Ms after completion of treatment.

Conclusion: Remnant LNs were relatively common on CT scan after 6 Ms treatment and significantly related with male gender and younger age. It might be no related with incomplete treatment or treatment failure.