Pathology Poster - A Fishy Matter - Fish Tank Granuloma
Dr Sampurna Roy MD
Fish tank granuloma:
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.
Fish tank granuloma seems to be a rare sporadic human disease that is often misdiagnosed.
Histopathological examination of involved synovium in patients with disease principally in this site shows hypertrophy and hyperplasia of synovial lining cells together with a fibrinous exudate.
The presence of granulomas is variable.
Granulomas, if present, tend to be well defined and non-caseating, but poorly defined granulomatous foci may be present in some cases, and in others suppurative inflammation may predominate.
Hyperkeratosis and pseudoepitheliomatous hyperplasia of the epidermis may be found in cutaneous infections.