Significance of early diagnosis and surgical management in treating Mycobacterium immunogenum-related pyogenic extensor tenosynovitis: a case report

Abstract

Background: Non-tuberculous mycobacteria (NTM) are environmental organisms that are increasingly contributing to human infections. Mycobacterium immunogenum, a variant of NTM discovered in 2001, is a rapidly growing mycobacterium that exhibits multidrug resistance. Reports of infections caused by this organism, particularly tenosynovitis in the musculoskeletal system, are limited.

Case presentation: A 71-year-old female with vesicular pemphigus, undergoing immunosuppressive therapy, presented with a progressively enlarging tumour on the dorsum of her right hand, along with erythematous papules that extended across her right forearm. The specimens of skin tissues and blood cultures revealed the presence of M. immunogenum. Magnetic resonance imaging evaluation led to the diagnosis of pyogenic extensor tenosynovitis. A multidrug regimen, comprising amikacin and clarithromycin, was initiated, followed by synovectomy. The patient underwent a course of 180 days of antimicrobial therapy and demonstrated no signs of disease recurrence one year after treatment completion.

Conclusion: Early diagnosis and surgical intervention are crucial to prevent the adverse prognostic implications of pyogenic extensor tenosynovitis caused by M. immunogenum. Effective management requires precise microbial identification and susceptibility testing, necessitating collaborative engagement with microbiological laboratories.

Keywords: Mycobacterium immunogenum; Nontuberculous mycobacterium; Pyogenic extensor tenosynovitis; Rapidly growing mycobacteria.

Fig. 1

Skin lesions on right forearm and hand Erythematous papules on the medial side of the right forearm and painless mass on the dorsal surface of the right hand (red arrow). The scattered white bullous lesions on the dorsum of the right hand are bullous pemphigoids

Fig. 2

Colonies and Ziehl-Neelsen staining of Mycobacterium immunogenum Colonies of Mycobacterium immunogenum grown on blood agar medium and on potato dextrose agar medium. Ziehl-Neelsen staining of a specimen taken from the right-hand tumour site reveals the presence of Mycobacterium immunogenum, which is indicated with a red arrow

Fig. 3

Magnetic resonance imaging of the right hand (left: T1-weighted images, right: T2-weighted images) Magnetic resonance imaging shows pyogenic extensor tenosynovitis around the extensor tendons of the right hand, which is marked by a red circle

Fig. 4

Findings before and after synovectomy White cake-like tissue is present within the synovium, and synovitis is present proximal to the extensor digitorum flavum. A Z-shaped incision is made through the extensor digitorum flavum and a synovectomy is performed to ensure that no remnants