Cluster of Lymphadenitis due to Nontuberculous Mycobacterium in Children and Adolescents 8-15 Years of Age.

Background: Nontuberculous mycobacteria (NTM) lymphadenitis is an under-recognized entity, and data of the true burden in children are limited. Without a high index of suspicion, diagnosis may be delayed and microbiological detection is challenging. Here, we report a cluster of NTM lymphadenitis experienced in Korean children. Methods: Subjects under 19 years of age diagnosed with NTM lymphadenitis during November 2016-April 2017 and April 2018 were included. Electronic medical records were reviewed for clinical, laboratory and pathological findings. Information regarding underlying health conditions and environmental exposure factors was obtained through interview and questionnaires. Results: A total often subjects were diagnosed during 18 months. All subjects were 8-15 years of age, previously healthy, male and had unilateral, nontender, cervicofacial lymphadenitis for more than 3 weeks with no significant systemic symptoms and no response to empirical antibiotics. Lymph nodes involved were submandibular (n = 8), preauricular (n = 6) and submental (n = 1). Five patients had two infected nodes and violaceous discoloration was seen in seven subjects. Biopsy specimens revealed chronic granulomatous inflammation and acid-fast bacteria culture identified Mycobacterium haemophilum in two cases and NTM polymerise chain reaction was positive in two cases. Survey revealed various common exposure sources. Conclusion: NTM lymphadenitis is rare but increasing in detection and it may occur in children and adolescents. Diagnosis requires high index of suspicion and communication between clinicians and the laboratory is essential for identification of NTM.