PATHOLOGY Department of Clinical Studies, School of Veterinary Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece Prevalence, Distribution and Factors Associated with the Presence and the Potential for Malignancy of Cutaneous Neoplasms in 174 Dogs Admitted to a Clinic in Northern Greece H.KALDRYMIDOU 1 ,L.LEONTIDES 2 ,A.F.KOUTINAS 3,4 ,M.N.SARIDOMICHELAKIS 3 andM.KARAYANNOPOULOU 3 Addresses of authors: 1 Department of Pathology, School of Veterinary Medicine, Aristotle University of Thessaloniki, University Campus, Thessaloniki; 2 Department of Epidemiology and Economics of Animal Production, School of Veterinary Medicine, University of Thessaly, 43100 Karditsa; 3 Department of Clinical Studies, School of Veterinary Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece; 4 Corresponding author: E-mail: sanimed@vet.auth.gr With 5 tables Received for publication April 27, 2001 Summary Onehundredandseventy-fourdogsdiagnosedwithcutaneous neoplasmsintheAnimalMedicalandSurgicalClinic,Faculty of Veterinary Medicine, Aristotle University of Thessaloniki, were studied. Thirty-one types of neoplasm were diagnosed, among which mast cell tumours 13.8%), hepatoid gland adenomas 9.8%), lipomas 5.7%) and histiocytomas 5.7%) were the most common. The prevalence of epithelial, mesen- chymal, lymphohistiocytic and melanocytic tumours was 47.7, 40.8, 8.6 and 2.9%, respectively. Potentially malignant neo- plasms were less frequently recorded than benign neoplasms. The tumours were single 80.5%) or multiple 19.5%) and locatedontheheadandneck18.4%),thebodytrunk49.4%), the limbs 25.9%) or at multiple sites 6.3%). The factors evaluated in multivariable logistic regression models for possible association with the odds of a tumour's potential for malignancyincludedtheage,thesexandthebreedofthedog, as well as the histological type of the neoplasm. Dogs with mesenchymal tumours had two times higher odds of potential formalignancythanthosewithepithelialtumours.Incontrast, dogswitheitherlymphohistiocyticormelanocytictumoursdid nothaveincreasedriskofmalignancycomparedwithdogswith epithelial tumours. The odds of tumour malignancy linearly increasedwithincreasingageofthedogbyafactorof1.1per year.Finally,theeectofthesexandthebreedofthedogon theriskofdevelopingcutaneousneoplasmswasinvestigatedin anage-matchedcase±controlsampleof348dogsbyconditional logistic regression analysis. The odds of neoplasm presence weretwotimeshigherinpurebreddogsthaninmongrelsbut didnotdierbetweencross-breedsandmongrels. Introduction The skin is the most common site of occurrence of canine neoplasms and almost 30% of all neoplasms reported in this species arise in the skin Priester and Mantel, 1971; Bostock, 1986). The incidence of cutaneous neoplastic tumours is approximately 728 cases every year per 100 000 dogs Dorn et al., 1968; Moulton, 1978). The continuous exposure of the integument to a wide variety of chemical and physical insults along with its accessibility to direct observation may explain the reported high prevalence of these tumours among all neoplasms Hueper, 1963). Many surveys of the prevalence, predilection sites and sex, breed and age effects on the occurrence of canine skin neoplasms have been published Brodey, 1970; Finnie and Bostock, 1979; Ladds et al., 1983; Bostock, 1986; Rothwell et al., 1987; Er and Sutton, 1989; Goldschmidt and Shofer, 1992). The results show consider- able variation from region to region that could be attributed mainly to environmental in¯uences and differences in breed population Strafuss, 1985; Goldschmidt and Shofer, 1992). This study aimed to: a) provide data regarding the preval- enceanddistributionofseveraltypesofskinneoplasmandb) investigate associations between possible risk factors and the potentialformalignancyofneoplasmsinasampleof174dogs diagnosedwithskinneoplasiainaclinicinnorthernGreecein theperiodfrom1984to1996.Inaddition,thelikelyeectofthe sex and the breed of the dog on the likelihood of developing skin neoplasms was also examined. This information has not beenpublishedpreviouslyforaGreekcaninepopulation. Materials and Methods Cases The population of cases comprised 174 dogs with cutaneous neoplasms that had been admitted to the out-patient service of the Animal Medical and Surgical Clinic, Faculty of Veterinary Medicine, Aristotle University of Thessaloniki. Some additional cases n  9) were excluded from the study because data regarding the sex, breed and age of the dog as U. S. Copyright Clearance Center Code Statement: 0931±184X/2002/4902±0087 $15.00/0 www.blackwell.de/synergy J.Vet.Med.A 49, 87±91 2002) Ó 2002 Blackwell Wissenschafts-Verlag, Berlin ISSN 0931±184X