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CASE REPORT Surgical removal of a canine orbital lipoma A 10-year-old, female, neutered Cairn terrier was presented with CASE HISTORY a progressively enlarging, cream-white ﬂuctuant subconjunctival A 10-year-old, neutered, female Cairn ter- swelling in the right eye. A ﬁne-needle aspirate performed under rier weighing 14 kg was presented with a history of a slowly enlarging, painless, topical anaesthesia showed that the mass contained lipomatous white mass in the dorsal conjunctival for- tissue. Orbital ultrasonography showed the mass to have a distinct nix. The dog had been managed for obe- sity from the age of two years, with a border and to extend into the posterior orbit. The mass was removed commercial calorie-control diet and via a conjunctival incision. It had a distinct capsule anteriorly, while had previously had lipomatous inguinal masses removed surgically. At the age of the border of the mass was less readily identiﬁed in the posterior eight years, she had been presented with orbit. Histopathological examination showed the mass to be a a white mass evident under the conjunc- tiva in the right eye. After referral to vet- lipoma. The dog recovered uneventfully from surgery, and no erinary ophthalmologists at a specialist recurrence has been noted after 12 months. centre, the differential diagnosis of lym- phoma or prolapse of the orbital corpus adiposum was suggested. A ﬁne-needle D. L. WILLIAMS AND E. HAGGETT* INTRODUCTION aspirate biopsy was performed demon- strating lipomatous tissue with a very Journal of Small Animal Practice (2006) low cell harvest, and the latter diagnosis 47, 35–37 Orbital neoplasms are seen rarely in the dog, almost always present as slowly was considered as being conﬁrmed. progressing, painless exophthalmos in Two years later, the white swelling had older dogs, and are often malignant. enlarged to the point that conjunctivitis A wide variety of tumour types can was evident with engorged conjunctival occur in the orbit, with ﬁbroma, menin- vessels (Fig 1). The dog was represented gioma, oseteosarcoma, and lymphosarcoma with ocular irritation as corneal ulceration being reported (Kern 1985, Hendrix had occurred. The dog was treated with and Gelatt 2000). Orbital neoplasms topical fusidic acid (Fucithalmic Vet; can be primary, arising in the orbit, Leo Laboratories) and referred for assess- or, less commonly, secondary, invading ment to the primary author (D. L. W.). from adjacent structures. The majority More detailed ophthalmic examination of primary orbital neoplasms in the showed no degree of third eyelid pro- dog are malignant, with regional inﬁltra- trusion or any exophthalmos but a 4 mm tion or distant metastasis being common. ventral deviation of the globe and a large Most orbital neoplasms are extraconal ﬂuctuant white mass protruding from and thus result in exophthalmos, often the dorsal conjunctival sac was obvious with lagophthalmos and protrusion of (Fig 1). A degree of lagophthalmos was the nictitating membrane. An intraconal noted, which was caused by the size of mass such as a meningioma may present the palpebral lesion with ocular surface as exophthalmos without third eyelid exposure, and is presumed to have led protrusion, and a small number of to the corneal ulceration previously diag- orbital tumours do present with subcon- nosed. The epithelial erosion had healed, junctival swelling; of 15 cases of lobular with a small area of subepithelial ﬁbrosis orbital adenoma in a recent study, ﬁve evident, together with ocular surface pig- presented with subconjunctival masses mentation, again presumed to be a manifes- and two with retrobulbar space-occupy- tation of exposure keratitis. Schirmer tear ing lesions (Headrick and others tests were 17 mm/minute in the right eye Department of Clinical Veterinary Medicine, 2004). Here, we present a benign, orbital and 14 mm/minute in the left. Intraocular University of Cambridge, Madingley Road, space-occupying lesion with an unusual pressure, as measured by applanation Cambridge CB3 OES presentation and with a lipomatous tonometry (Tonopen XL; Veterinary Spe- *House and Jackson Veterinary Surgeons, Chevers Pawn, Rookery Road, Blackmore, Ingatestone, pathology as yet unreported in the ciality Products), was 16 mmHg in the Essex CM4 0LE canine orbit. right eye compared with 14 mmHg in Journal of Small Animal Practice Á Vol 47 Á January 2006 Á ª 2006 British Small Animal Veterinary Association 35 David L. Williams & Emily Haggett FIG 1. Subconjunctival mass in upper eyelid FIG 3. Conjunctiva incised (arrows deﬁne retracted conjunctival edges) to reveal anterior extent of orbital mass FIG 5. Mass after removal from orbit the left. Ultrasonography identiﬁed a well- demarcated lesion hyperechogenic when compared with the surrounding orbit con- or of a lipoma. Prolapse of the corpus adi- tents (Fig 2) and extending from the pos- posum is widely recognised in human terior limit of the orbit to the conjunctival beings (Monner and others 1998) and fornix, which was markedly displaced ante- has previously been reported in horses riorly. A provisional diagnosis of orbital (Bedford and others 1990) and in dogs lipoma was made, and the dog was prepared (Boydell and others 1996). The pathology for transconjunctival surgery to remove the in these cases is then a malpositioning of mass. normal orbital fat because of breakdown The tumour was resected under general of connective tissue normally holding anaesthesia; a conjunctival incision was the tissue in the orbit. In the present case, made over the mass (Fig 3) and blunt dis- although this diagnosis had been sug- section was used to separate the mass from gested on examination at another specialist surrounding orbital tissues (Fig 4). Very FIG 4. After blunt dissection the mass is centre, the progression in size of the lesion limited haemorrhage was encountered, removed through the dorsal conjunctival and its ultrasonographic appearance sug- and dissection of the mass was simple until incision gested a neoplastic process rather than the posterior limit of the mass was reached when tumour margins became somewhat Leo Laboratories) and analgesia provided indistinct. Following excision of the mass, with 2 mg/kg oral carprofen (Rimadyl; the conjunctiva was closed with 0Á8 metric Pﬁzer) for ﬁve days. coated polyglactin 910 (Vicryl; Ethicon) The mass measuring 4x2x1 cm (Fig 5) and the dog was discharged with topical ﬂoated upon ﬁxation in 10 per cent formol fusidic acid antibiosis (Fucithalmic Vet; saline, suggesting a lipomatous origin. His- topathology conﬁrmed the mass to be pre- dominantly composed of adipocytes with some inﬂammatory cell inﬁltrate and a thin, ﬁbrous capsule at the periphery of the lesion (Fig 6). No recurrence was noted over 12 months of follow-up. DISCUSSION The presentation of this case, with a pre- vious demonstration of lipid material FIG 6. Histopathology of the mass haematoxylin FIG 2. Ultrasonogram showing extent of mass in subconjunctivally, suggests a diagnosis of and eosin x200. Note adipocytes and capsule orbit (arrows) bar 1 cm either a prolapsed orbital corpus adiposum (arrows) 36 Journal of Small Animal Practice Á Vol 47 Á January 2006 Á ª 2006 British Small Animal Veterinary Association Surgical removal of a canine orbital lipoma merely an aberrant anatomical positioning tumours in 1990 reported only 0Á3 per CONCLUSION of normal orbital fat. cent to be lipomas. The question has to Orbital neoplasia has been widely be asked in Forrest’s series, then, as in Here we present what is apparently the reported in the dog as noted above (Kern the present case, whether the lesions ﬁrst reported case of canine orbital lipoma, 1985, Hendrix and Gelatt 2000) but reported to be lipomas actually repre- with an unusual presentation as a slowly normally as an extraconal space-occupying sented normal orbital fat. What differen- enlarging cream-white dorsal conjunctival orbital lesion with exophthalmos and pro- tiates a low-grade lipoma from normal mass. Resection with a transconjunctival trusion of the nictitating membrane. The orbital fat and thus leads us to suggest that approach was successful in resolving the dorsal position of the lesion here might sug- the lesion presented here is a lipoma rather condition. gest a neoplasm of the lacrimal gland, as has than another case of orbital fat prolapse? been previously reported in the dog (Wang Lipoma suggests not the abnormal and others 2001). The ﬁnding of fat on position of normal orbital fat but rather References ﬁne-needle aspirate biopsy strongly sug- a neoplastic increase in the size of the BEDFORD, P. G., BARNETT, K. C., BOYDELL, P. & HAIZELDEN, gested a diagnosis of orbital lipoma or lipo- orbital adipose tissue. Lipoma is benign N. (1990) Partial prolapse of the antero-medial corpus adiposum in the horse. Equine Veter- matous haemangiopericytoma. The latter in appearance both grossly and on histo- inary Journal Ophthalmology Supplement 2 10, neoplasm has been reported in the orbit pathology, so mere observation of the 2-4 in human beings and in dogs (Goldsmith mass at the time of resection cannot easily BELTRAN, W. A., COLLE, M. A., BOULOUHA, L., DAUDE- LAGRAVE, A., MOISSONNIER, P., CLERC, B. (2001) A and others 2001, Beltran and others be used to differentiate orbital fat prolapse case of orbital hemangiopericytoma in a dog. Vet- 2001) and may have lipomatous elements from lipoma. It is the behaviour of the erinary Ophthalmology 4, 255-259 (Davies and others 2002). Haemangioper- mass over time which differentiates orbital BOYDELL, P., PATERSON, S. & PIKE, R. (1996) Orbital fat icytoma, as a relatively aggressive vascular fat prolapse (essentially a non-progressive prolapse in the dog. Journal of Small Animal Prac- tice 37, 61-63 tumour is, however, to be differentiated lesion) from lipoma (a slowly enlarging DAVIES, P. E., DAVIS, G. J., DODD, T., SELVA, D. (2002) from lipoma on histopathological and space-occupying mass). The ultrasono- Orbital lipomatous haemangiopericytoma: an behavioural grounds. graphic appearance of the lesion in this unusual variant. Clinical and Experimental Oph- thalmology 30, 281-283 To our knowledge, orbital lipoma, dog suggests a marked increase in size of GOLDSMITH, J. D., VAN DE RIJN, M., SYED, N. (2001) Orbital a widely recognised tumour in human the corpus adiposum enlarging over time. hemangiopericytoma and solitary ﬁbrous tumor: beings, has not been reported in dogs. It is normally difﬁcult to demarcate such a morphologic continuum. International Journal of Surgical Pathology 9, 295-302 The orbit contains the globe, the optic a corpus adiposum in the dog on orbital HEADRICK, J. F., BENTLEY, E. & DUBIELZIG, R. R. (2004) nerve, the extraocular muscles, the con- ultrasonography, and Boydell’s case series Canine lobular orbital adenoma: a report of 15 nective tissue, and the neurovascular struc- found no abnormality in appearance in cases with distinctive features. Veterinary Oph- thalmology 7, 47-51 tures, all of which are surrounded by the dogs in which orbital ultrasonography HENDRIX, D. V., GELATT, K. N. (2000) Diagnosis, treat- adipose tissue. Any of these tissues can was undertaken. Here, preoperative ment and outcome of orbital neoplasia in dogs: undergo neoplastic change, but it is con- orbital ultrasonography demonstrated that a retrospective study of 44 cases. Journal of Small Animal Practice 41, 105-108 sidered that fat is the tissue which is least the majority of the hyperechoic lesion was KERN, T. J. (1985) Orbital neoplasia in 23 dogs. Jour- likely to develop neoplastic change. In located in the posterior orbit and extended nal of American Veterinary Medical Association human beings, the prevalence of orbital posteriorly almost to the posterior wall of 186, 489-491 MONNER, J., BENITO, J. R., ZAYUELAS, J., PALOMA, V., lipomas in published series of orbital the orbit, a ﬁnding conﬁrmed at surgery. CASTRO, V. & SERRA, J. M. (1998) Transconjunctival tumours ranges from 0 to 11 per cent. While ventral deviation of the globe was herniation of orbital fat. Annals of Plastic Surgery In two large series of orbital tumours, evident, it was the mass that protruded 41, 658-661 WANG, F. I., TING, C. T., LIU, Y. S. (2001) Orbital ad- Forrest’s study of 222 cases from 1949 both subconjunctivally and thus extraorbi- enocarcinoma of lacrimal gland origin in a dog. reported 19 (8Á6 per cent) to be lipomas, tally rather than the globe being displaced Journal of Veterinary Diagnostic Investigation while Henderson’s review of 764 orbital forward. 13, 159-161 Journal of Small Animal Practice Á Vol 47 Á January 2006 Á ª 2006 British Small Animal Veterinary Association 37
"Surgical removal of a canine orbital lipoma"