br Introduction Nontuberculous mycobacteria NTM are opportun

Introduction Nontuberculous mycobacteria (NTM) are opportunistic pathogens that can cause lung, skin/soft tissue, lymphatic, or disseminated infections, mainly in immunocompromised patients. Mycobacterium avium complex (MAC) consists of several closely related slow-growing nonchromogens of NTMs, including M intracellulare. MAC accounts for the largest portion of all NTM infections in most epidemiologic series. They are environmental organisms widely distributed in soil, water, and animals. The routes of infection include inhalation, ingestion, or direct inoculation by trauma or medical procedures. Disseminated NTM infections usually occur in patients with acquired immunodeficiency syndrome (AIDS), and they have been reported sporadically in patients with other forms of immunosuppression. We report a rare case of disseminated cutaneous MAC infection in an immunocompetent patient.
Case report A man aged 54 years was referred to our clinic for slowly progressing asymptomatic eruptions. The lesions began first on the right arm 2 years ago and additional lesions developed shortly after. On inspection, erythematous indurated papules and nodules were present on his right arm, left cheek, right ankle, and back (Figure 1). None of the lesions showed surface changes of erosion, ulceration, or desquamation. The skin biopsy in the referring hospital showed granulomatous inflammation of the dermis and subcutis with negative periodic acid-Schiff (PAS) and acid-fast stain for microorganisms. The tissue cultures for bacteria, fungi, and mycobacteria were all negative. Under the diagnosis of granuloma of unknown causes, methotrexate and thalidomide were prescribed without improvement. We performed a skin biopsy from the right arm lesion that showed noncaseating granulomatous inflammation involving superficial dermis and subcutis with scattered multinucleated giant lorcaserin hydrochloride (Figures 2 and 3). The PAS and acid-fast stains were negative. Two months later, the tissue culture grew a nontuberculous mycobacterium. The isolate was negative for niacin accumulation, catalase at 68°C, hydrolysis of Tween 80, or arylsulfatase at 14 days. The colonies of the isolates were buff after 14 days of incubation. Confirmation of these isolates to the species level was performed by partial 16S rRNA gene (1464 bp) analysis using two primers (primers 8FPL and 1492) as described previously. The sequences were compared with known 16S rRNA gene sequences in the GenBank database of the National Center for Biotechnology Information using the basic local alignment search tool (BLAST) algorithm. The species of all the isolates with the best match was M intracellulare (accession number AY859027.1, 98% identity). No lymphadenopathy was present, and the tests for human immunodeficiency virus (HIV) and antinuclear antibody were negative. Serum protein electrophoresis revealed normal immunoglobulin levels. After a 4-month treatment with oral clarithromycin 500 mg twice daily and levofloxacin 500 mg daily, the lesions resolved with residual hyperpigmentation (Figure 4). There was no recurrence of the lesions 2 years after completion of the treatment. The follow-up chest X-ray and computer tomography showed focal areas of fibroreticular shadows within the bilateral upper lungs consistent with old tuberculosis.
Discussion Disseminated NTM infections usually occur in patients with AIDS or other forms of immunosuppression. The typical manifestations of disseminated MAC infections are fever, night sweats, and weight loss, with fever being the most common presentation. Disseminated cutaneous MAC infections have an extremely rare occurrence rate in immunocompetent patients, and most of the reports are from Japan (Table 1). Concurrent non-cutaneous foci, including lymph nodes, joints, bone marrow, or lung were present in one-half of the cases (seven out of 14). Six out of the seven cases with isolated cutaneous MAC infections had ulcers, discharge, or fistula. Thus in some of these patients, the development of multiple skin lesions may represent autoinoculation and not true dissemination. Papulonodules without surface changes, as seen in our patient, were present in four cases (Cases 1, 6–8). In three out of the four cases (Cases 1, 6–7), cervical lymphadenopathy was also present.