부산대학교 도서관

Most cases of lymphadenitis caused by nontuberculous mycobacteria (NTM) are noted in pediatric patients, with few reports in adults, except in immunocompromised patients. We report a case of anterior auricular lymphadenitis caused by NTM in a healthy 41-year-old male adult. He was referred to the Department of Otolaryngology at Chiba University Hospital because of a mass in the front part of the right ear, which was suspected to be a parotid tumor. On initial examination, a 20-mm-sized, poorly mobile induration was felt under the right anterior ear skin. Ultrasonography revealed a mass with indistinct borders and irregular margins extending from near the capsule of the upper pole of the right parotid gland to the subcutaneous tissue. Magnetic resonance imaging showed contrast effect in the capsular portion, but a mass lesion was noted in the interior portion with little contrast effect. Puncture aspiration cytology showed no malignant findings, suggesting a granulomatous lesion with inflammation. Mycobacterial culture and polymerase chain reaction analysis of puncture specimens showed negative findings. On close examination, an abscess was observed, which burst naturally, and the pus was submitted for culture. Mass spectrometry and genetic analysis revealed Mycobacterium mageritense, rapidly growing mycobacteria, as the causative organism. Upon consulting with the Department of Infectious Diseases, the patient was started on drug therapy with sulfamethoxazole/trimethoprim and levofloxacin. However, after 2 months of treatment with the antimicrobial agent, the patient showed little improvement; therefore, we decided to perform surgical resection under local anesthesia. Pathological findings showed caseous epithelioid granulomas, suggestive of lymphadenitis caused by NTM. Treatment strategies for rapidly growing mycobacteria have not been established, and tailored treatment for individual cases need to be developed, considering the patients’ background, lesion status, and drug sensitivity.