the scientific journal of the veterinary faculty university - Slovenian ...

106 A. Nemec, Z. Pavlica, P. Juntes, D. A. Crossleywell differentiated cuboidal or tall columnar epithelialcells with mild pleomorphism, only limited areasshowing greater pleomorphism. The cells of a transitionalcarcinoma subtype revealed greater variabilityof cell shape and size, from smaller basaloidcells to larger tall columnar and spindle-shaped orpolygonal cells with moderate amount of pale eosinophiliccytoplasm and hyperchromatic nuclei containingone or two, and rarely several, small nucleoli.Mitotic figures were rare in both parts.The dog was much better while on meloxicamand the owner was advised to proceed with staging.In view of the final diagnosis the owner was offeredreferral for a CT scan prior (3, 5) to possible radiationtherapy.DiscussionPeriodontal disease is the most common chronicinfectious disease in dogs affecting a majority of themature population (6, 7), with small breeds beingpredisposed to it (8). Tumours of the nasal and paranasalsinuses are rare in most domestic species butare recognised most frequently in dogs. The prevalence,however, is only 0.3 to 2.4%, with medium tolarge dolichocephalic breeds being more often affected.The higher risk associated with a long nosemay be related to the larger surface area of nasal epitheliumand with the filtering capability, althougha genetic basis in some breeds is also suspected (9).Incidence of nasal tumours also increases with ageof the dog, the mean age being reported as 9 to 10years (10, 11). Despite the low prevalence, however,Tasker (12) reports that neoplasia is the most commondiagnosis in dogs with persistent nasal disease(one third of cases), where as periodontal disease isonly recognized as the cause in 10% of cases. Adenocarcinomais the most frequent malignant nasaltumour recognized in dogs (9, 10) with transitionalcarcinoma being the second most common, both beingrare or not reported in other animal species (4).Acinic cell carcinoma or even neuroendocrine carcinomacan not been ruled out completely in this caseas differentiation requires immunohistochemistry,which was not performed. As neuroendocrine carcinomais an uncommon sinonasal tract neoplasmwith aggressive clinical behaviour (13, 14) this differentialdiagnosis was not consistent with clinicaland histomorphological findings in the presentedcase.The diagnostic approach to a patient with nasaldischarge includes obtaining a complete historysupported by thorough physical examination androutine blood tests to rule out systemic disease (1).If the results are normal as in the presented case,complete oral examination is the next step as wellas nasal swabs for cytology and culture if fungal diseaseis suspected, before proceeding to imaging andrhinoscopy with biopsy sampling (1). However, bloodtest results may be normal in dogs with nasal neoplasiaas paraneoplastic disorders associated withnasal tumours are rare in dogs (10).As advanced periodontal disease with oronasalfistulae at the maxillary canine teeth was detectedin this case, the chronic serous bilateral nasal dischargewas suspected to be of dental origin, especiallywhen the nasal discharge completely disappearedon the right side after the first dental treatment (extractionof the right maxillary canine tooth and closureof the fistula at that site), but remained on theuntreated site. As the discharge from the left nostrilalso temporarily disappeared after extraction of theleft maxillary canine tooth and antibiotic and antiinflammatorytreatment, dental disease must havehad an influence on the nasal discharge, thoughthe improvement may have been due to suppressionof secondary bacterial infection in the nasalcavity with the use of antibiotics (11). After unilateralrecurrence of the signs, inadequate healing ofthe oronasal fistula was considered the most likelydifferential diagnosis (15). Once this was ruled outfurther investigation was required to identify thecause. Nasal neoplasia most often presents initiallywith unilateral nasal discharge, epistaxis, epiphoraand facial deformity occurring in more advancedcases (11). When there is only serous discharge andexpiratory stertor, as our case, chronic rhinitis andnasopharyngeal dysfunction have also to be considered.It is impossible to say, what the primary diseasewas or if there is any link between the two diseasesin the present case as periodontal disease isextremely common in older small breed dogs andadenocarcinoma, although not a common condition,is seen most often in older dogs. Both conditionshave chronic courses, clinical signs persistingfor months (1, 6, 10, 11). It is well established thatchronic inflammation and/or infection with certainorganisms (particularly toxin producing spirochetes)prediposes to carcinoma in certain sites but therehave not been any reports suggesting a link betweenperiodontitis and nasal carcinoma (16, 17). Oral lichenplanus, a chronic inflammatory disease seenin man is reported to be clinically associated with