Canine Aural Papilloma - an Unusual Case

Canine aural papilloma 28 CANINE AURAL PAPILLOMA - AN UNUSUAL CASE Nalubamba KS1, Mumba C1 1. University Of Zambia, School Of Veterinary Medicine, P.O. Box 32379, Lusaka, Zambia Correspondence Dr. Chisoni Mumba, University Of Zambia, School Of Veterinary Medicine, P.O. Box 32379, Lusaka, Zambia Corresponding author: sulemumba@yahoo.com Nalubamba KS, Mumba C. Canine aural papilloma – an unusual case. Case Study and Case Report 2014; 4(1): 28-31. ABSTRACT Aural papillomavirus-induced papillomata were diagnosed on the ear of a seven-monthold German shepherd cross-bred dog in the absence of cutaneous or oral involvement. The aural papillomata lesions in this case were surgically removed after they failed to regress completely following initial immunomodulatory therapy. Histopathology revealed thickened epithelium which rested on proliferative connective tissue with elongation of dermal papillae into the dermal tissue and covered by acanthotic hyperkeratotic epidermis. In the granular cell layer, large numbers of cells were undergoing degeneration and showing vacuolated cytoplasm. Following surgical excision the dog recovered uneventfully. The significance of this case lies in the location (aural) which is quite rare as compared to other locations in which this case has been reported in veterinary medicine. To the author’s knowledge, this represents the first reported case of aural papilloma in Zambia and probably in Africa. Key words: Aural papilloma, histopathology, dog, Zambia INTRODUCTION Papilloma in livestock are quite common being located in different anatomical sites specific for each species; oral for the canine, and for the bovine they tend to be cutaneous. Canine papillomata are caused by canine oral papilloma virus (COPV) and three clades of the eight virus clusters, CPV1 to CPV8, have been reported 1, that have different clinical predilection sites and present as exophytic cutaneous papillomatosis, pigmented epidermal plaques; and exophytic papillomata. The virus has a predilection for the oral mucosae but other sites have been reported 2. Cutaneous COPV lesions are infrequently reported 3, and associated with immunosuppression 2. Canine aural papillomata are extremely rare with only one case reported in literature from India 4, and none reported in Africa. Diagnosis of canine papilloma may be made from typical clinical presentation of the lesions as pedunculated, sessile and possessing a cauliflower-like appearance grossly and from histopathology or PCR identification of the virus 5. Histopathology is very cardinal in the diagnosis of this condition. Regression of the Case Study and Case Report 2014; 4(1): 28-31. 28 Canine aural papilloma 29 COPV lesions involves complex immunological mechanisms and lymphocytic infiltration 6 , and complete regression occurs before most patients are two years old and recurrence does not commonly occur 7. Treatment of papilloma involves immunomodulatory therapy and surgical excision although some cases may be refractory to these modes of case management 8. The live COPV vaccine has been associated with numerous problems including neoplasia formation, while vaccination with formalin inactivated COPV is reported to lead to effective protection 9. The significance of this case lies in the location (aural) which is quite rare as compared to other locations in which this case has been reported in veterinary medicine. To the authors' knowledge, this article presents the first case of canine aural papilloma reported in Zambia and most probably in Africa. CASE REPORT A seven-month-old German shepherd cross-breed was presented with a mass occluding the external ear canal and resulting in a foul smelling discharge. Clinical examination revealed two distinct but closely apposed growths measuring 2.5 cm x 2.5 cm and 0.7 x 0.8 cm pedunculated, sessile sea anemone-like/cauliflower-like masses on the proximal concave part of the inner auricle of the left ear near the external acoustic meatus (Figure 1). Vital parameters were within normal reference values and blood was collected and haematology did not reveal any abnormalities. Due to the typical signalment and clinical presentation of the lesions a diagnosis of papilloma was reached. Due to financial limitations of the owners, the case was initially treated with immunomodulatory levamisole (Leviject®, 2mg/kg q48 hr, for four treatments, Dopharma, Netherlands) and penicillin/streptomycin ((Penstrep®200,000 IE penicillin, 200mg streptomycin/ml), equivalent 20mg streptomycin/kg, Dopharma, Netherlands)) antibiotics, followed by oral cloxacillin at 15mg/kg body weight q8hr for 21 days. The foul smelling discharge from the ear diminished but no regression of the lesion occurred after three weeks of therapy. Four weeks after the cessation of antibiosis, the foul smelling discharge had recurred and the owners then opted for surgical excision with cauterization. The area was aseptically prepared for surgery. Anaesthesia was achieved with intramuscular xylazine and ketamine, following premedication with atropine. The masses were each reflected and cut at the stalk-like base with a hot cautery knife to reveal small pinpoint lesions where the masses had been attached. Post-operatively, the patient was given penstrep® injections and discharged the following day on oral cloxacillin. Followup visit two weeks post-operatively revealed a fully healed ear with good patient health and no recurrence of papilloma lesions reported six months post-operatively. The excised masses were cut longitudinally, fixed in 10% neutral buffered formalin, and sent to The University of Zambia, School of Veterinary Medicine Pathology Laboratory for histopathologic examination. Thin paraffin sections were prepared routinely and stained with Haematoxylin and Eosin (H&E) for histopathological examination. Microscopic examination of the neoplasm revealed a thickened epithelium, proliferative connective tissue with elongation of pegs (dermal papillae) into the dermal tissue (Figure 2). Oil immersion (x100 magnification) revealed cells undergoing degeneration and showed vacuolated cytoplasm (Figure 3). Case Study and Case Report 2014; 4(1): 28-31. 29 Canine aural papilloma 30 2 1 3 Figure 1. Shows masses/growths measuring 2.5 cm x 2.5 cm and 0.7 x 0.8 cm pedunculated, sessile sea anemone-like/cauliflower-like masses on the proximal concave part of the inner auricle of the left ear near the external acoustic meatus. Figure 2. Shows a thickened epithelium which rested on proliferative connective tissue with elongation of (dermal papillae) pegs into the dermal tissue and covered by acanthotic hyperkeratotic epidermis (HE X40). Figure 3. Shows the prickle cell layer, single cells or groups of cells have a vacuolated cytoplasm. In the granular cell layer large numbers of cells were undergoing degeneration and show vacuolated cytoplasm (HE X100). DISCUSSION After the initial consultation, the owners opted to use an immunostimulant to increase local immunity in the hope of speeding up regression of the lesion and antibiotics to treat the infection. Levamisole and oral ivermectin have been advocated for, and used as immunostimulants in the treatment of papilloma with varying success rates being reported. In this case the levamisole therapy was not successful. This could have been due to the advanced nature of the lesions leading to non-responsiveness to levamisole. Levamisole is also reported not to be consistently immunostimulatory 8. Cutaneous melanoma were also ruled out as melanoma normally lack the typical exophilic and 'cauliflower-like' surface. Canine papillomas would normally regress with age 6, but in this case surgery was necessitated due to the location of the papilloma that was aesthetically unacceptable by the owners and as the exudate from the ear was foulCase Study and Case Report 2014; 4(1): 28-31. 30 Canine aural papilloma 31 smelling and draining into the ear canal. It was feared that if left unattended to, it would eventually lead to an infection of the middle and inner ear with more serious sequela. Similar considerations have been made, in the rare instances when this neoplasia occurs in the ear of humans 10. Cutaneous papillomata are rare and often associated with immunosuppression 10. However, this case did not have any history, clinical signs or haematological evidence of immunosuppression. During a follow up telephone consultation six months post-operatively, the owner reported no recurrence of the lesions. This lack of recurrence is consistent with what is reported in literature 7. COMPETING INTERESTS The authors declare no conflict of interest. REFERENCES 1. Lange CE, Tobler K, Ackermann M, Panakova L, Thoday KL, Favrot C. Three novel canine papillomaviruses support taxonomic clade formation. J. Gen. Virol. 2009; 90: 2615 - 21. 2. Sundberg JP, Smith EK, Herron AJ, Jenson AB, Burk RD, Van Ranst M. Involvement of canine oral papillomavirus in generalized oral and cutaneous verrucosis in a Chinese Shar Pei dog. Vet. Pathol. 1994; 31: 183 - 7. 3. 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Resolution of persistent oral papillomatosis in a dog after treatment with a recombinant canine oral papillomavirus vaccine. Vet. Comp. Oncol. 2003; 1: 57 - 63. 9. Bell JA, Sundberg JP, Ghim S, Newsome J, Jenson AB, Schlegel R. A formalininactivated vaccine protects against mucosal papillomavirus infection: A Canine Mode. Pathobiology. 1994; 62: 194 - 8. 10. Samar Pal SY, Rakesh C, Neeraj G, Seema C. Aural papillomatosis in a 3-yearold child. Int J Pediatr Otorhi. 2002; 66: 185 - 7. Case Study and Case Report 2014; 4(1): 28-31. 31