In canine cutaneous disorders such as AD and mastocytosis, MCs can be a key diagnostic element [14], but unfortunately, our results showed that this technique is not usable for c-kit assessment, as non-neoplastic MCs show, in addition to membrane positivity, strong cytoplasmic positivity; however, it is practicable in the case of the immunohistochemical study of nuclear and membranous markers. The gene discussed is KIT; the disease is Alzheimer disease.