OCULAR DERMOID IN A DOG AND ITS SURGICAL CORRECTION

Sidhartha Sankar Behera1, Biswadeep Jena1, Indramani Nath2, Monalisa Behera3 and Susen
Kumar Panda3
1Assistant Professor, 2Professor & Head, Department of Veterinary Surgery and Radiology, 3Department of Veterinary Pathology, College of Veterinary Science and Animal Husbandry, OUAT. Bhubaneswar-751003 (Odisha). [Received: 24.4.2018; Accepted: 25.10.2018] {DOI 10.29005/IJCP.2018.10.2.177-179}

One German shepherd dog was presented with complaint of abnormal hair growth on cornea of its right eye and
there was chronic epiphora and blepharospasm. The case was diagnosed as dermoid and advised for surgical correction. Under general anaesthesia the abnormal mass was resected and membranoplasty followed by tarsorrhaphy were done. On the 10th post-operative day sutures over the eyelids were removed and the dogs had an uneventful recovery with normal vision.
Keywords: Dermoid, Dog, Surgical intervention.

Dermoid is a choristoma which is a histologically normal tissue in an abnormal location (Martin, 2005) and choristomas are benign congenital over growths of heterotopic cutaneous tissue in an inappropriate place
(Cook, 2007). Occular dermoids are composed of dermis like connective tissue containing skin, hair follicles, blood vessels, nerves, smooth muscles, fibrous tissue, sebaceous and sweat glands, adipose tissue, covered by keratinised stratified squamous epithelium (Brudenall et al., 2007). It has been observed in several domestic animals,
including dogs, cats, horses, cattle, sheep, guinea pigs, rabbits, birds and also in wild animals like wild beest (Erdikman et al., 2012). Among dogs the more predisposition breed to ocular dermoids are German shepherds (GSD), Saint Bernard (SB), Golden retriever and Dachshund (Brudenall et al., 2007). The ocular dermoids may affect the eyelids, conjunctiva (bulbar and palpebral), nictitating membrane or cornea or
may be seen as an inclusion cyst within the orbit (Wappler et al., 2002). Lee et al. (2005) observed that due to direction of hairs towards eye there was chronic irritation resulting epiphora, blepharospasm and keratitis. It is commonly believed that, ocular dermoid is generally congenital, but not hereditary (Lee et al., 2005).
Case History and Observations A one year old German shepherd dog was presented to Department of Surgery and
Radiology with complaint of abnormal hair growth in its right eye. The patient had suffered from chronic epiphora, ocular discharge and blepharospasm. On ophthalmic examination, right eye revealed presence of longer and thickened hair tuff against cornea (Fig.1). The case was diagnosed as ocular dermoid and advised for surgical correction.

Treatment
The dog was kept 24 hours fasting and then sedated using Xylazine hydrochloride @ 1 mg/kg body weight and Ketamine hydrochloride @ 5 mg/kg body weight in cocktail mixture intramuscularlyafter the
admiistration of pre anesthethic atropine sulphate @ 0.04 mg/kg body weight (I/M). Normal saline solution (NSS) administration was maintained throughout the operation to give additional amount of Ketamine hydrochloride when needed. The patient head was placed on the operation table with the affected eye uppermost and the head was
positioned for the surgeon to operate with ease. Stay sutures were placed in the bulbar conjunctiva for fixation of the globe. Then the hairy abnormal tissue was resected by superficial keratectomy and the excised tissue
was sent for histopathological study. Eye drops containing tobramycin were instilled and then membranoplasty followed by tarsorrhaphy were done (Fig. 2 and 3). Postoperatively antibiotic ceftriaxone @ 10 mg/kg
body weight for 5 days and meloxicam @ 0.2 mg/kg body weight for 3 days were administered, I/M. Eye drop was continued four times daily for 10 days through the gap between the sutures on eyelids. The eye was protected from damage by placing an Elizabethan collar over neck and covering cloths over the paw. On the 10th postoperative
day sutures over the eyelids were removed.

Results and Discussion The dog had an uneventful recovery with normal vision (Fig.4). In the present case
the dermoid was at limbus region and was unilateral in origin similar to the findings of Martin (2005) where the most common site of corneal dermoid in the dogs was at the temporal canthus and most of them were unilateral. Ocular dermoids are best treated by surgical excision (Keratectomy and/or conjunctivectomy) and superficial
keratectomy is preferred where cornea is involved as also reported by Slatter and Dietrich (2003). Cases where corneal defect is larger than 25% of the corneal surface bulbar pedicle graft is adopted where as cases
with defects less than 25% of the cornea are treated with tarsorraphy as also mentioned by Erdikmen et al. (2012). In the present case there was slight injury during removal of the abnormal tissue and the dermoid was less
than 25% of the corneal surface. So membranoplasty followed by tarsorrhaphy was preferred for quick healing.
Histopathology of the excised mass revealed numerous, large, well-developed hair follicles and other adnexal structures. In some areas moderately hyperplastic, keratinized stratified squamous epithelium overlying a thick
collagenous stroma (Fig.5) were observed.

References
Brudenall, D.K., Bernays, M.E. and Peiffer, R.L. (2007). Central corneal dermoid in a Labrador retriever puppy. J. Small Anim. Pract., 48: 588-590.

Cook, C.S. (2007). Ocular embryology and congenital malformations. In, Gelatt K N (Eds.): Veterinary Ophthalmology. 4th edn., Blackwell, Oxford, U.K. Pp. 21-22.

Erdikmen, D.O., Aydin, D., Saroglu, M., Guzel, O., Hasimbegovic, H., Ekicl, A., Gurel, A. and Ozturk, G.Y. (2012).
Surgical correction of ocular dermoids in dogs: 22 cases. Kafkas Uni. Vet. Fak. Derg., 19: 7618.

Lee, J., Kim, M.J., Kim, I.H., Kim, Y.B. and Kim, M.C. (2005). Surgical correction of corneal dermoid in a dog. J. Vet. Sci., 6: 369-370.

Martin, C.L. (2005). Corneal and sclera. In, Ophthalmic Disease in Veterinary Medicine. 1st edn., Manson Publishing Ltd., London, U.K. Pp. 282.

Slatter, D.J. and Dietrich, U. (2003). Cornea and sclera. In, Slatter DJ (Eds.): Text book of Small Animal Surgery. 3rd edn., Saunders, Philadelphia, U.S.A.Pp. 1379- 1391.

Wappler, O., Allgoewer, I. and Schaeffer, E.H. (2002). Conjuctival dermoid in two guinea pigs: A case report. Vet
Ophthalmol, 5: 245-248.

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