Objective: To study the clinical features, epidemiology and outcome of nontuberculous mycobacterial lymphadenitis (NTML).
Methods: A retrospective study was performed on 54 patients under 14 years old diagnosed with atypical mycobacterial lymphadenitis between 1987 and 2004. Inclusion criteria were: (i) positive polymerase chain reaction (PCR) test or culture; (ii) positive sensitin skin test 6 mm above Mantoux; (iii) histopathologic features compatible with mycobacterial infection and/or positive direct smear for acid-fast bacilli, Mantoux reaction less than 15 mm, a normal chest radiograph, absence of exposure to an adult with tuberculosis, negative Mantoux test reactions in family members, and exclusion of other causes of granulomatous adenitis.
Results: Fifty-four patients were included in the study. The number of NTML cases increased notably from 1996, coinciding with a decrease in cases of tuberculous adenitis. The mean age was 35 months (range: 14 months-6 years). Submandibular nodes were involved in 22 of 63 cases of adenitis (34.9%) and cervical nodes were involved in 21 (33.3%). In 8/42 patients (19%) the tuberculin skin test was larger than 10 mm. Cultures were positive in 52.9% of the cases (18/34) and PCR in 53.3% (8/15). The most frequently isolated mycobacteria was Mycobacterium avium (61%). Therapy failed in 8/21 patients receiving antibiotics (38%), in 10/13 patients with drainage alone (77%) and in none of the patients who underwent surgery (8/8).
Conclusions: Nontuberculous mycobacterial adenitis has become more frequent in our hospital since 1996. Cultures do not always allow isolation of mycobacteria and the Mantoux test frequently yields false positive results, thus hampering diagnosis. The most effective treatment was surgical excision. Nevertheless, when the surgical approach is difficult or there is postoperative recurrence, pharmacological treatment can be useful.