The term epulis has been used to describe localized gingival enlargement and encompasses both non-neoplastic reactive and neoplastic lesions
(Yoshida et al., 1999). Epulides, tumors of periodontal ligament origin, are common in dogs but occur infrequently in cats (
Gardner, 1996;
Colgin et al., 2001; Castro et al., 2011). Despite rare in cats, epulides were studied by
Colgin et al., (2001) and de
Bruijn et al., (2007) in 13 and 52 cases respectively. But documentation of epulides among wild animals is scarce. Fibromatous epulis was reported in an aged male lion at Brasília Zoo Hospital, Brazil
(Castro et al., 2011) and in an adult male tiger, at São Paulo, Brazil
(Fecchio et al., 2009). Rossi et al., (2007) studied diseases of periodontal origin among jaguars (
Panthera onca) in captivity of state of São Paulo.
Dental pathology is common in captive bears, primary dental disease syndromes are fractured teeth, caries and periodontal diseases (
Collins, 2015). Retrospective survey of the available literature failed to detect any report of epulis in sloth bears (
Melursus ursinus) and this paper might be the first to report bilateral epulides in a sloth bear with its successful surgical management.
Case history and observation
During November 2011, one male sloth bear (approx. body weight 40 kg) aged about 15 years at Nandankanan Zoological Park developed bilateral swellings at the upper jaw, protruding out of the oral cavity, impeding with the normal feeding and drinking. The animal used to rub these swellings against the hard surfaces of the enclosure resulting in abrasions which further lead to ulcerative complications. The animal was immobilized for detailed physical examination. Close observation and radiography images revealed that the swellings are bilateral epulides at the upper jaw involving canines of both sides (Fig 1). The condition warranted immediate surgical intervention and it was decided to excise the epulides one after another.
Treatment
The first surgery was carried out at Zoo Veterinary Hospital, Nandankanan Zoological Park, Odisha during November 2011. The bear was immobilised using a drug mixture of 80 mg xylazine hydrochloride (0.8 ml Xylazil 100, Troy Laboratories Pty Ltd., Smithfield, NSW, Australia) @ 2 mg/kg b. wt and 200 mg ketamine hydrochloride (2.0 ml Ketamil 100, Troy Laboratories Pty Ltd., Smithfield, NSW, Australia) @ 5 mg kg b. wt darted intramuscularly through blow pipe. The bear attained complete sternal recumbency after 11 minutes of drug injection. Radiograph images revealed no alveolar bone involvement (Fig 3). The epulis of the left gum was first surgically removed (Fig 2), bleeding vessels were ligated, adrenaline soaked gauzes were applied and the wound was sutured. Blood samples were collected with anticoagulants (EDTA and fluoride) and clot activator vials for further laboratory investigation. All the procedures were completed within 45 minutes of induction of the anaesthesia and it was reversed using 5 mg of Yohimbine HCl (0.5 ml Reverzine, Bomac Pty Limited, Hornsby, NSW 2077). The bear was housed in the ‘Indoor Ward’ of the zoo hospital for round the clock observation and provided with only liquid diet for two days. Intramuscular broad spectrum antibiotics and analgesics were administered for five days and supplemented with oral multivitamins for fifteen days. After three months of first surgery, in March 2012, the bear was re-operated under general anaesthesia using the same drug and epulis of the right gum was removed following the same procedure (Fig 4). The bear achieved uneventful recovery and started taking normal food after five days of second surgery.
The mouth cavity was examined at regular intervals and no recurrence of epulides was found.
Histopathology
The left epulis weighed 45 gm, was of size 7.5 cm×5 cm with 3.5 cm thickness and the right epulis weighed 40 gm, was of size 7 cm×5.2 cm with 3.2 cm thickness. The specimens were fixed in 10% neutral buffered formalin and bisected along their longer axis with a scalpel blade. Specimens that were hard to cut or included bone were decalcified after fixation. Tissues were embedded in paraffin, sectioned at 5 μm and stained with hematoxylin and eosin (HE)
(Yoshida et al., 1999).
Histopathology of the operated mass, conducted at Department of Veterinary Pathology, College of Veterinary Science and Animal Husbandry, Odisha University of Agriculture and Technology, Bhubaneswar, Odisha, revealed it as fibromatous and ossifying epulis (Fig 5 and 6). The unencapsulated well vascularized neoplasm was composed of fibrous tissue of stellate and spindle shaped cells with moderate amount of collagenous matrix. There were no mitotic figures with mild inflammatory reaction. The overlying gingival epithelium revealed moderate hyperplasia with a moderate down growth of rete ridges occasionally showing anastomoses. Islands and spicules of variedly mineralized, bony matrix containing irregularly spaced, often empty, lacunae were present within the fibroblastic proliferative tissue.
