A Clinical, Microbiological, and Pathological Study of Cutaneous Nontuberculous Mycobacterial Infection

Jang, Min Soo; Han, Sang Hwa; Kim, Sang Tae; Suh, Kee Suck

Abstract

BACKGROUND
As the immunocompromised population has increased in recent years, the number of cutaneous nontuberculous mycobacterial (NTM) infections has also risen. However, since this affliction has no pathognomonic clinical or histological features, the diagnosis and treatment of cutaneous NTM infections are often delayed.
OBJECTIVE
The aim of this study was to investigate the microbiological, clinical, and histological findings of cutaneous NTM infections.
METHODS
We reviewed medical records and histologic slides of 10 patients diagnosed with cutaneous NTM infections confirmed by culture or polymerase chain reaction.
RESULTS
All patients except one were immunocompetent, and 5 of 10 patients had preceding factors including trauma, liposuction, and intralesional triamcinolone injection. Microbiologically, of the 10 infections, 5 were caused by Mycobacterium marinum, 3 by Mycobacterium fortuitum, and 1 each by Mycobacterium chelonae and Mycobacterium ulcerans, respectively. Of the 5 patients with M. marinum, 2 had a fish-related job and 1 reared fish at a home aquarium. The most common clinical presentation was erythematous nodules (7/10). Histologically, irregular acanthosis (4/10), mixed cell infiltrate of lymphocytes, histiocytes, neutrophils (9/10), suppurative granuloma (7/10), microcysts lined by neutrophils (5/10), fibrosis (4/10), and panniculitis (7/10) were identified.
CONCLUSION
We found microcysts lined by neutrophils in 50% of the samples and considered this finding to be a diagnostic marker of NTM infection. These clinicopathologic features will assist clinicians in diagnosing NTM infection more rapidly and accurately.