The class A macrophage scavenger receptor CD204 is a useful immunohistochemical marker of canine histiocytic sarcoma.

The immunohistochemical expression of the class A macrophage scavenger receptor CD204, was investigated in 50 canine histiocytic sarcomas (HSs) and compared with that of CD18, CD163, CD11d and class II molecules of the major histocompatibility complex (MHC). Expression of CD204 was also determined in 81 canine round cell tumours and pleomorphic sarcomas including T- and B-cell lymphomas, mast cell tumours, extramedullary plasmacytomas, cutaneous histiocytomas, transmissible venereal tumours, pigmented or amelanotic melanomas, poorly differentiated haemangiosarcomas and rhabdomyosarcomas. All of the 50 HSs expressed CD204, CD18 and MHC class II; 27 were positive for CD163 and seven expressed CD11d. All of the round cell tumours, except for one grade III mast cell tumour, were negative for CD204; however, they showed varying immunoreactivity patterns for CD18 and MHC class II. None of the pleomorphic sarcomas were immunoreactive for CD204. CD204 would appear to be a useful marker for canine HS.

A pathological study of sepsis associated with sarcoptic mange in raccoon dogs (Nyctereutes procyonoides) in Japan.

The pathological findings in Japanese raccoon dogs with sarcoptic mange infection associated with death from sepsis are described. Microscopical lesions of the skin were consistent with those described previously in wildlife populations with Sarcoptes infection, but secondary lesions were also present in the lungs, heart, kidneys, liver, spleen and brain of these animals. This infection was therefore very similar to "crusted scabies" or "Norwegian scabies" in man and was characterized by severe pathology and high mortality, with deaths frequently occurring due to sepsis.