Morphological Features and KIT Receptor Expression in Canine Cutaneous Mast Cell Tumor and Systemic Mastocytosis / Morfološke Karakteristike I Ekspresija KIT Receptora Kod Kutanih Mastocitoma I Sistemske Mastocitoze Pasa

Abstract

Abstract Mast cell neoplasia in dogs can occur in two different forms: common as cutaneous tumor, or less common as a systemic form of neoplastic mast cell proliferation - systemic mastocytosis. The aim of this study was to compare the histological and cytological features, KIT receptor expression and presence of c-KIT proto-oncogene mutations in neoplastic cells of dogs with canine cutaneous mast cell tumor (CMCT) and systemic mastocytosis. Microscopical examination of the cytological smears obtained from all selected dogs revealed that cellular specimens were constituted mostly of round cells with a central nuclei and fine to coarse purple cytoplasmic granules. Histopathological examination of skin samples of dogs with CMCT and a dog with systemic mastocytosis showed proliferation of the neoplastic mast cells in the superficial and/or deep dermis. Similar findings were observed in tissue samples derived from lymph nodes, spleen, liver, myocardium and kidneys of a dog with systemic mastocytosis. Three dogs with high grade CMCT as well as one dog with systemic mastocytosis showed cytoplasmic CD117 expression, while 3 dogs with low grade CMCT, had membranous expression of CD117. Based on our study, histological features and cytoplasmic CD117 expression in neoplastic cells of dogs with systemic mastocytosis are similar to those in dogs with high grade CMCTs. Nevertheless, mutations of c-KIT proto-oncogene were not found in tumor samples either from dogs with CMCT or dog with systemic mastocytosis. Neoplazme poreklom od mastocita mogu da se jave u dva različita oblika: uobičajeno kao kožni tumori - kutani mastocitomi ili ređe kao sistemska forma neoplastične proliferacije mastocita - sistemska mastocitoza. Svrha ovog istraživanja je da se uporede histološke i citološke karakteristike, ekspresija KIT receptora i prisustvo mutacija c-KIT proto-onkogena u neoplastičnim ćelijama kod pasa sa kutanim mastocitomima i sistemskom mastocitozom. Mikroskopskim pregledom citoloških razmaza svih ispitanih pasa utvrđeno je da se ćelijska populacija sastoji uglavnom od okruglih ćelija koje imaju centralno postavljeno jedro i sitne ljubičaste citoplazmatske granule. Histopatološkim pregledom uzoraka kože pasa sa kutanim mastocitomima i sistemskom mastocitozom zapaženo je umnožavanje mastocita u površinskom i/ili dubokom dermisu. Sličan nalaz uočen je i u isečcima tkiva limfnih čvorova, slezine, jetre, miokarda i bubrega psa sa sistemskom mastocitozom. Kod tri psa sa kutanim mastocitomima visokog stepena maligniteta, kao i kod psa sa sistemskom mastocitozom zapažena je citoplazmatska ekspresija CD117, dok je kod tri psa sa kutanim mastocitomima niskog stepena maligniteta uočena membranska ekspresija CD117. Na osnovu našeg istraživanja, histološke karakteristike i citoplazmatska ekspresija CD117 na neoplastičnim ćelijama su slične kod pasa sa sistemskom mastocitozom i pasa sa kutanim mastocitomima visokog stepena maligniteta. I pored toga, mutacije c-KIT proto-onkogena nisu uočene ni kod pasa sa kutanim mastocitomima, ni kod psa sa sistemskom mastocitozom.