Lymphadenitis is a common manifestation of MAC and atypical mycobacteria in children aged one to five years (17). MAC appears to have replaced M. scrofulaceum as the most common etiologic agent for scrofula in young children (18). In individuals aged 12 years and older, M. tuberculosis remains the most common etiologic agent, and a suspicion for more disseminated disease and immunosuppression should arise in these patients (19). Other atypical mycobacteria seen are M. scrofulaceum, M. malmoense (in northern Europe), M. abscessus, M. fortuitum, M. lentiflavum, M. tusciae, M. palustre, M. interjectum, M. elephantis, and M. heidelbergense. Infection usually presents as a firm, painless, erythematous mass without fluctuance or systemic symptoms, which is bilateral in 10% of cases. Sinus tracts and fistulas can form as the condition becomes chronic.
Diagnosis is difficult, and the differential should include bacterial infections, cancer, lymphomas, TB, and bartonellosis. Chest radiographs are typically normal and the TST is negative unless the patient has been previously vaccinated with BCG.
FNA can be used for diagnosis, but the yield of positive AFB smears is low (around 30-50%). Excisional biopsy provides more tissue for diagnosis and is also curative. AFB cultures are important to isolate the infectious agent and for reliable antibacterial susceptibility testing.
Was this article helpful?