Case report: Secondary neck mass infection in a patient with multiple osteomyelitis caused by Corynebacterium striatum.

Rationale: The opportunistic pathogen Corynebacterium striatum has been generating more clinical infections in recent years, but secondary infections at different parts caused by it have been reported more rarely.

Patient Concerns: This case details a 52-year-old male patient who got an infection that advanced to multiple osteomyelitis and soft tissue abscess after block therapy for external humeral epicondylitis of the right arm. Unexpectedly, the chronic ulcerated region of the patient's neck was infested with Corynebacterium striatum due to inadequate treatment of the main infection, resulting in a secondary infection of the neck mass.

Diagnoses: Microbiological cultures of the pus from the right elbow and neck indicated an infection with Corynebacterium striatum at both sites.

Interventions: We initiated antimicrobial therapy with linezolid (600 mg) in conjunction with Fosfomycin (4 g) every 12 hours.

Outcomes: After 4 weeks of treatment, the infected lesion was resolved as evidenced by a repeat magnetic resonance imaging compared to the prior scan.

Lessons: This case not only demonstrates the significant pathogenicity of Corynebacterium striatum but also warns that traumatic locations, such as swellings resulting from chronic ulcers in the neck, may become prospective targets for this bacterium.