To evaluate the histopathological features observed in patients with cutaneous infections due to nontuberculous mycobacteria (NTM) and to compare the histopathological patterns observed in immunosuppressed patients and normal hosts. Twenty-eight biopsy specimens corresponding to 27 patients with cutaneous infections due to NTM were reviewed. Eighteen biopsies corresponded to normal hosts (14 Mycobacterium marinum, 2 Mycobacterium chelonae, 1 Mycobacterium terrae and 1 Mycobacterium gordonae) and 10 biopsy specimens were obtained from 9 immunosuppressed patients (3 Mycobacterium chelonae, one of which had two biopsies, 1 Mycobacterium abscessus, 2 Mycobacterium kansasii, 1 Mycobacterium marinum, 1 Mycobacterium avium complex and 1 Mycobacterium simiae). A panel of histopathological features was evaluated by two independent observers in each biopsy specimen. Epidermal changes (acanthosis, pseudoepitheliomatous hyperplasia, exocytosis) were mainly observed in M. marinum infections. In immunosuppressed patients the infiltrate tended to be deeper, involving the subcutaneous tissue (100%) with a more diffuse distribution and constant abscess formation. A marked granulomatous inflammatory reaction was observed in 83% of immunocompetent and in 60% of immunosuppressed patients. In immunosuppressed patients a relationship between the chronic evolution of the disease and granuloma formation was demonstrated. A diffuse infiltrate of histiocytes with occasionally foamy appearance was noted in three biopsy specimens from three patients with AIDS. Acute and chronic panniculitis was detected in 8 biopsy specimens. In one biopsy (M. chelonae) an acute suppurative folliculitis was observed. Different histopathological patterns can be noted in biopsy specimens from cutaneous nontuberculous mycobacterial infections. The evolution of the disease and the immunologic status of the host may explain this spectrum of morphological changes. Tuberculoid, palisading and sarcoid-like granulomas, a diffuse infiltrate of histiocytic foamy cells, acute and chronic panniculitis, non-specific chronic inflammation, cutaneous abscesses, suppurative granulomas and necrotizing folliculitis can be detected. Suppurative granulomas are the most characteristic feature in skin biopsy specimens from cutaneous NTM infections. Some histopathological patterns seem more prevalent in immunosuppressed patients.
Cutaneous manifestations of nontuberculous mycobacterial infections may be classified according to criteria such as cutaneous lesions and immune status.
All cases of MM diagnosed in 23 Hospitals in Catalonia, from 2000 to 2007 were recorded and its incidence calculated and adjusted for the European standard population through the direct method. The age standardized rate varied from 6.74 in 2000 to 8.64 in 2007 for all melanomas and from 4.79 to 5.80 for invasive MMs, the Breslow thickness being stable during the period. The increase in invasive melanoma incidence in the elderly was remarkable, the crude rate increasing from 11.04 (2000) to 15.49 (2007) in the 60–64 yr population, while remaining more stable from 3.97 in 2000 to 4.55 in 2007 for the age range of 30–34 ys or with a tendency to decrease from 5.1 in 2000 to 2.5 in 2007 for age range of 25–29 yr, age ranges much more affected by immigration. Despite the large immigrant population (nearly one million immigrants that arrived in Catalonia during the study period from countries with a low melanoma incidence), melanoma incidence in our region has risen considerably and this trend will likely persist in the near future.
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