[Fish breeder granuloma: infection caused by Mycobacterium marinum and other atypical mycobacteria in the human. Analysis of 8 cases and review of the literature].

Granulomatous lesions of the skin and tendon sheaths after exposure to fish tank or aquarium water are frequently caused by non-tuberculous so-called atypical mycobacteria. Mycobacterium marinum is the species most often isolated from such lesions. Rarely, other non-tuberculous species of mycobacteria may be isolated. In contrast to swimming-pool granuloma as the epidemic form of Mycobacterium marinum infection of man, fish tank granuloma seems to be a rare sporadic human disease that is often misdiagnosed. We report eight cases of fish tank granuloma. Five patients had sporotrichoid lesions, and one patient had a singular lesion. Three patients presented with tenosynovitis. Culture-proven Mycobacterium marinum infection was found in four patients, in one patient the causative organism isolated from the biopsy specimen was identified as Mycobacterium kansasii. In three patients with typical appearance of the lesions and exposure to fish tank water, biopsy specimens for culture were not available, and the diagnosis was histopathologically confirmed. Surgical treatment had an unfavourable outcome in two of three patients. Conservative antimicrobial therapy was evaluated in six patients. Similar to published reports, the treatment with rifampicin in combination with other agents seemed to be a useful therapy. Complete remission was, however, also achieved with doxycycline monotherapy. Microbiological diagnosis should be attempted in suspected cases of fish tank granuloma, and, if therapy is indicated, we strongly suggest primary medical treatment.