Surgical Management of Squamous Cell Carcinoma of External Ear in a Dog.
A male Pomeranian dog was presented with history of tumor like mass developing in left ear since last one year. Physical examination revealed mass measured 1.5 centimetre in diameter. Fine needle aspiration cytology revealed absence of cyst, abscess and haematoma. Under general anaesthesia, surgical correction was resorted to. The tumor mass was excised by making an elliptical incision at the base of the mass and bleeding was arrested by using electrocautery. Histologically tumor was identified as squamous cell carcinoma involving external ear. Routine post-operative therapy was given and animal had an uneventful recovery.
Keywords: Dog; external ear; squamous cell carcinoma
Squamous cell carcinoma of external ear is a rare condition in animals.Tumors of the ear in dogs and cats are relatively uncommon representing 1-2 percent of all tumors in cats (Rogers, 1988) and 6 percent of all tumors in dogs (Little et al., 1989). Tumors of pinna occur at all ages in dogs and cats. These tumors are most commonly seen in middle aged to older animals. Benign or malignant tumor can develop in external ear of dogs and cats, and arise from apocrine or ceruminous glands that line the ear. Ceruminous gland adenocarcinomas (malignant tumors) are more commonly seen than benign form (adenomas) in both dogs and cats. There is increased risk for tumors in animals that have history of chronic otitis. The treatment of choice for ear tumor is surgical excision. This study aimed to report better a case of Squamous Cell Carcinoma of external ear and its surgical management.
Materials and Methods
A four year old male Pomeranian dog weighing seven kg was presented with history of tumour mass developing in left ear since one year. On physical examination, a mass was present in left external ear measuring 1.5 centimetre in diameter. Fine needle aspiration cytology revealed it as tumor. Otoscopic examination revealed normal middle ear structures with accumulation of cerumen. Radiographic examination of thorax (Fig. 1) and skull (Fig. 2) was ruled out for metastasis of tumor. The physiological parameters were within the normal range. Hence there was no evidence of metastasis, under general anaesthesia surgical excision of the tumor mass was resorted to.
Pre-operatively, Ceftriaxone sodium was administered @ 25 mg/kg b. wt. intravenously. Dog was premedicated with Atropine sulphate @ 0.045 mg/kg b.wt. Xylazine @ 1 mg/kg b.wt. and Butorphanol @ 0.2 mg/kg b.wt. intramuscularly. General anaesthesia was induced using combination of Diazepam @ 0.2 mg/kg and Ketamine hydrochloride @ 5 mg/kg b.wt. intravenously. The animal was positioned in right lateral recumbency with affected ear facing upwards. The surgical area was prepared aseptically. An elliptical incision was made all around the base of tumor mass and bleeding was arrested using electrocautery. The wound lips were left unsutured since, the ear canal was too narrow and suturing would lead to disfigurement of ear. On histopathological examination tumor was identified as squamous cell carcinoma (Fig. 5). Routine postoperative care was taken and owners were advised to provide cage rest. Meloxicam @ 0.2 mg/kg b. wt. and Cephalexin @ 20 mg/kg b. wt. were administered orally for 5 days.
Results and Discussion
The animal recovered uneventfully without any further complications. Squamous cell carcinoma (SCC) is an uncontrolled growth of abnormal cells arising in squamous cells, which compose most of skin's upper layers (epidermis). SCCs often look like scaly red patches, open sores, elevated growths with central depression, or warts; they may crust or bleed. Malignant neoplasms of ear canal in dogs and cats are most commonly carcinomas of ceruminous gland and squamous cell and of undetermined origin (Legendre etal, 1981; Withrow et al., 1996). The neoplasms commonly associated with external ear include ceruminal gland or sebaceous adenoma or adenocarcinoma, papilloma, ceruminal gland carcinoma, histiocytoma, mast cell tumor, basal cell carcinoma, malignant melanoma and squamous cell carcinoma (Slatter, 2003).
Surgical excision can be curative for benign tumors that are completely removed. Aggressive surgery is the treatment of choice for malignant tumors and often involves removal of ear and cleaning out inner ear (bulla osteotomy). This surgery is often referred to as a total ear canal ablation. Radiation therapy can be utilized in some cases to slow the growth of tumour or relieve pain. This can also be used for curative intent when surgical excision is incomplete. Chemotherapy may be recommended, if tumour appears to be aggressive on biopsy or if there is evidence of metastasis (Slatter, 2003).
Legendre, A.M. and Krahwinkel, D.J. (1981). Feline ear tumors. J. Am. Anim. Hosp. Assoc. 17: 1035-37.
Little, C.J.L., Pearson, G.R. and Lane, J.G. (1989). Neoplasia involving the middle ear cavity of dogs. Vet. Rec. 124: 54-57.
Rogers, K.S. (1988). Tumors of the ear. Vet. Clin. North Am. Small Anim. Pract. 18: 859-68.
Slatter, D. (2003). Pinna. In: Text Book of Small Animal Surgery. 3rd Ed. p. 1737-46.
Withrow, S.J. and Vail, D.M. (1996). Tumors of the skin and subcutaneous tissues. In Withrow S.J., MacEwen EG (eds): Small Animal Clinical Oncology. WB Saunders, Philadelphia, p. 167-91.
Siddhartha Savale (1), K.S. Kamalesh Kumar (2) and Basavaraj (3)
Department of Veterinary and Animal Husbandry Extension Education College of Veterinary and Animal Sciences Kerala Veterinary and Animal Sciences University (KVASU) Pookode Wayanad--673576 (Kerala)
(1.) Post Graduate Scholar and Corresponding author. E-mail: email@example.com
(2.) Post Graduate Scholar
(3.) Veterinary Surgeon, Pet Clinic, Rajajinagar, Bengaluru
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|Title Annotation:||Short Communication|
|Author:||Savale, Siddhartha; Kumar, K.S. Kamalesh; Basavaraj|
|Date:||Jul 1, 2016|
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