Clostridium perfringens gas gangrene in a canine splenic liposarcoma.

Histotoxic clostridial infections occur when clostridial spores germinate in anaerobic tissue environments and release a variety of extracellular toxins, causing necrosis, secondary inflammation, and often death. These infections are seen in humans and animals, especially ruminants and horses, but are rare in dogs. An 11-y-old, intact male Border Collie-cross dog was inappetent and lethargic after abdominal blunt-force trauma. Clinical examination and imaging revealed a splenic mass containing gas and an abdominal effusion, identified cytologically as a neutrophilic exudate. At splenectomy, an area on the anti-hilar surface of the mass was abscessed, with inspissated material on the mass surface and in the omentum. Histopathology identified a splenic liposarcoma with areas of necrosis, suppuration, emphysema, and colonization by large gram-positive bacilli. These were identified as Clostridium perfringens by immunohistochemistry. The bacteria are presumed to have translocated from the bowel and germinated in a region of tumor necrosis secondary to traumatic ischemia. To our knowledge, gas gangrene has not been reported previously within a visceral tumor in a dog.