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[[Image:Small Animal Dermatology Q&A 10.jpg|centre|500px]]<br>
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[[Image:Small Animal Dermatology Q&A 11a.jpg|centre|500px]]<br>
 
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'''A 6-month old Siamese cat with multiple cutaneous nodules on its head, face, and ears is presented for examination. Skin biopsy findings reveal a histiocytic MCT.'''
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'''An intensely pruritic dog was presented for examination. The dog’s pruritus developed acutely approximately 3 weeks ago. The dog had no history of skin disease prior to this episode. The dog was normal on physical examination except for being intensely pruritic and having ‘scaly’ elbows. The organism shown was found on a skin scraping from the elbow of the patient.'''
    
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<FlashCard questions="3">
 
<FlashCard questions="3">
|q1=What is the cat’s prognosis?
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|q1=What is the organism?
 
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*The prognosis is good. These tumors in young Siamese cats (<4 years of age) usually undergo spontaneous remission.
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''Sarcoptes scabiei'' mite.
*These lesions also can be seen in non-Siamese kittens and will also resolve spontaneously.
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*Adult cats of other breeds with widespread lesions should be evaluated carefully as these cats tend to have visceral involvement.
   
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|q2=What are the three major clinical presentations of MCT in cats?
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|q2=What clinical signs are associated with this parasite infestation?
 
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The three forms of clinical presentation are cutaneous, lymphoreticular or visceral, and gastrointestinal.  
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This is a highly contagious mite that causes intense pruritus. The history of an acute onset of intense pruritus is common. The mites burrow in thinly haired areas, and intense ventral pruritus may be the first clinical sign noted. In many cases, there is a history of exposure to affected dogs or high-risk exposure situations (e.g. stray dogs, boarding kennel, visit to a grooming facility, visit to a park). In many patients, lesions may be absent but thinly haired areas, the ventrum, elbows, and ear margins, are often good sites to find mites. Both deep and superficial skin scrapings should be done to increase the chances of finding the mites.
#The visceral form involves a combination of the liver, spleen and/or abdominal lymph nodes.  
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#The cutaneous form is limited to the skin.
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#The gastrointestinal form is usually a primary tumor and is the third most common intestinal tumor in cats after lymphoma and adenocarcinoma (Thamm and Vail, 2001). These tumors usually arise from the small intestine. Eosinophilia may be present.<br><br>
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Clinical signs of lymphoreticular and gastrointestinal MCTs are indistinguishable:
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*vomiting,  
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*diarrhoea,  
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*depression,  
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*weight loss, and  
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*anorexia.
   
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|q3=What are the two histological subtypes of cutaneous MCT in cats?
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|q3=What new diagnostic test is available, and what are the limitations of the test?
 
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The two histological subtypes of feline mast cells are the histiocytic and mast cell type.
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Recently, an in vitro serum antibody test was marketed in Sweden for the diagnosis of this parasite. The test is reported to have a sensitivity of 83% and a specificity of 92% (Curtis, 2001).
#The histiocytic type occurs in young cats (<4 years of age) and is most common in Siamese cats. It frequently presents as subcutaneous nodules. Histologically, the mast cells are poorly granulated and lymphoid aggregates are common. Many of these tumors will spontaneously regress.  
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#The ‘mast cell form’ of cutaneous MCT tends to occur in mixed breed shorthaired cats. Lesions tend to be solitary and are discrete, nodular, papular, or plaque-like lesions in the dermis or subcutaneous tissue. It can also present as ‘miliary dermatitis’.
   
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</FlashCard>
 
</FlashCard>