Mycobacterium farcinogenes-induced lymphadenitis in a pediatric patient: a case report

Abstract Background Mycobacterium farcinogenes is primarily associated with bovine farcy and rarely infects humans. This report presents the first documented case of a 6-year-old girl diagnosed with lymphadenitis caused by Mycobacterium farcinogenes, resulting from a left submandibular mass. The case highlights the importance of maintaining vigilance for such infections, even in immunocompetent children. Case presentation A 6-year-old girl was hospitalized with a complaint of a “left submandibular mass for nearly 3 months.” Surgical biopsy and subsequent tissue culture confirmed the presence of Mycobacterium farcinogenes. Postoperatively, the patient was treated with a combination of clarithromycin and rifampicin, leading to substantial symptom resolution. She was discharged in stable condition 10 days after surgery. Following discharge, the patient continued the antibiotic regimen for an additional 6 months, with long-term follow-up at 9 months confirming sustained remission without recurrence. Conclusion This is the first report documenting the isolation of Mycobacterium farcinogenes from the pus of a child with lymphadenitis. The findings suggest that Mycobacterium farcinogenes should be recognized as a possible causative agent of skin and lymph node infections, even in children with intact immune systems. Successful treatment requires thorough surgical debridement accompanied by long-term targeted antibiotic therapy, which proved effective in this case.