Veterinary Ophthalmology (2015) 18, 5, 429–432
DOI:10.1111/vop.12223
CASE REPORT
Primary corneal melanocytoma in a Collie Bianca Bauer,* Marina L. Leis* and Soraya Sayi† *Departments of Small Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada; and †Prairie Diagnostic Services, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
Address communications to: B. Bauer Tel.: (306) 966-7083 Fax: (306) 966-7174 e-mail: [email protected]
Abstract A 6-year-old female, spayed Collie was referred to the Western College of Veterinary Medicine for a 12-month history of a progressive right corneal mass. A superficial keratectomy was performed and histopathology revealed a corneal melanocytoma with complete excision. There has been no recurrence of the neoplasm to date (12 months). This is the first known report of an isolated corneal melanocytoma in a canine. Key Words: canine, cornea, eye, histopathology, keratectomy, melanocytoma
INTRODUCTION
Primary corneal neoplasia is rare.1,2 Reports of canine corneal neoplasia include papilloma,3 limbal melanocytoma,4 squamous cell carcinoma,5 hemangiosarcoma,6 and lymphoma.1 Of all the corneal neoplasias, canine limbal melanocytomas are more frequently reported and typically appear as well circumscribed, heavily pigmented, raised masses which invade the adjacent cornea, conjunctiva, and sclera.4 To the authors’ knowledge, primary, central corneal malignant melanoma, or melanocytoma have not been reported in the dog. Malignant melanomas or melanocytomas originate from the transformation of melanocytes. This neoplasm arises from varying sites within the body and has extremely diverse biologic behaviors depending on size, stage, site, and histologic parameters.7 Reported ocular neoplasia of melanocytic origin include eyelid, conjunctival, limbal, and uveal malignant melanomas and melanocytomas.8 We report a case of an isolated corneal melanocytoma that was surgically resected with no recurrence to date. CASE REPORT
Clinical history A 6-year-old female, spayed Collie was referred to the Western College of Veterinary Medicine’s Veterinary Medical Centre for evaluation of a right corneal lesion. The corneal lesion had been present for at least 12 months according to the owner and was apparently growing slowly. The dog was predominantly housed outdoors and there was no previous history of trauma to the eye. Neuro-ophthalmic examination was within normal © 2014 American College of Veterinary Ophthalmologists
limits. Schirmer tear tests were 22 and 15 mm/min in the right and left eyes, respectively, and intraocular pressures with rebound tonometry were 12 and 13 mmHg in the right and left eyes, respectively. Biomicroscopic examination of the right eye revealed an exophytic irregular black corneal mass approximately 10 mm in diameter. This mass was noted to occupy approximately 40% of the central cornea and was protruding approximately 13 mm beyond the corneal surface. Surrounding this lesion was an approximately 4 mm area of white corneal opacification, most consistent with lipid (Fig. 1). The peripheral cornea was within normal limits 360 degrees other than the presence of superficial corneal vascularization extending toward this lesion at the 10:00 position. Fundic examination revealed mild choroidal hypoplasia temporally bilaterally with the remainder of the ophthalmic examination being within normal limits. A preliminary diagnosis of a corneal neoplasm was made. Possible differential diagnoses for the corneal mass included papilloma, pigmented squamous cell carcinoma, malignant melanoma, or melanocytoma. A superficial keratectomy was recommended and was performed.
Surgical procedure The dog was anesthetized and the eye was routinely prepared for surgery with dilute povidone iodine. The lesion was delineated with a 450-micron restricted entry blade, and a lamellar keratectomy was performed with the aid of an operating microscope. The lesion was excised in one piece without touching the tumor itself (no-touch technique) with a clear circumferential corneal margin of approximately 2 mm. The excised mass was placed in 10% neutral buffered formalin and submitted to Prairie
430 bauer, leis and sayi
Figure 1. Clinical picture of the right eye demonstrating the exophytic irregular black corneal mass with surrounding corneal degeneration.
Diagnostic Services for histological evaluation. Recovery from anesthesia was uneventful and the patient was discharged from the hospital with topical ciprofloxacin and diclofenac four times daily and atropine once daily for the right eye for 14 days.
Histopathology Tissues were processed routinely for histology. Paraffin embedded sections were cut at 4 lm and stained with hematoxylin and eosin (H&E). Further sections were ‘bleached’ with 1% aqueous potassium permanganate. Histologically, the corneal mass was well circumscribed, nonencapsulated, and composed of heavily pigmented neoplastic melanocytes which were arranged in sheets, nests, and packets separated by small amounts of a fibrous stroma. The cell details were obscured by abundant dark brown to black cytoplasmic pigment (melanin) (Fig. 2). Corneal neovascularization was noted within the superfi-
Figure 2. Hematoxylin and eosin stained section of the corneal mass (409). The cells contained abundant melanin pigment.
Figure 3. Bleached section of the corneal mass (409). Neoplastic cells were large and round to polygonal.
cial corneal stroma. In the bleached sections where cell detail was evident, neoplastic cells were large and round to polygonal with distinct cell borders and contained abundant foamy cytoplasm (Fig. 3). The nuclei were round to ovoid with stippled chromatin and variably distinct nucleoli. The mitotic activity was low (3 mitosis in 10 HPF) is the best indicator of malignancy. These criteria may also be useful for ocular melanocytic neoplasia.18,19 The classification and behavior of the various canine melanocytic tumors are also influenced by anatomic location.7,9 Although canine ocular melanocytic tumors may share a similar cytological and histological appearance, the biolog-
ical behaviors and appropriate therapies can vary based on anatomic site. For example, melanocytic tumors arising from the canine conjunctiva are typically malignant due to a high degree of local invasiveness and metastatic propensity9,20,21, yet melanocytic tumors arising from the haired skin of the canine eyelid are typically behaviorally benign.9,22 Despite malignant characteristics of some human corneal tumors, distant metastasis is seldom observed11,13 and it has been suggested that isolated malignant corneal melanoma cannot metastasize due to the lack of corneal lymphatics.23 The histologic appearance of this canine melanocytic tumor and the lack of tumor recurrence 12 months following keratectomy support a benign behavior. The corneal pigmentation observed upon follow-up examination is attributed to wound-healing24; however, the case will continue to be monitored long-term for mass recurrence. REFERENCES 1. Ledbetter EC, Gilger BC. Diseases and Surgery of the Canine Cornea and Sclera. In: Veterinary Ophthalmology, 2. 5th edn. (eds Gelatt KN, Gilger BC, Kern TJ) John WIley & Sons Inc., Ames, IA, USA, 2013; 976–1049. 2. Wilcock B. The eye and ear. In: Pathology of Domestic Animals, 1. 4th edn. (eds Jubb KVF, Kennedy PC, Palmer NC) Academic Press, San Diego, CA, 1993; 441–529. 3. Bernays ME, Flemming D, Peiffer RL Jr. Primary corneal papilloma and squamous cell carcinoma associated with pigmentary keratitis in four dogs. Journal of the American Veterinary Medical Association 1999; 214: 215–217, 04. 4. Donaldson D, Sansom J, Scase T et al. Canine limbal melanoma: 30 cases (1992-2004). Part 1. Signalment, clinical and histological features and pedigree analysis. Veterinary Ophthalmology 2006; 9: 115–119. 5. Dreyfus J, Schobert CS, Dubielzig RR. Superficial corneal squamous cell carcinoma occurring in dogs with chronic keratitis. Veterinary Ophthalmology 2011; 14: 161–168. 6. Haeussler DJ Jr., Rodriguez LM, Wilkie DA et al. Primary central corneal hemangiosarcoma in a dog. Veterinary Ophthalmology 2011; 14: 133–136. 7. Spangler WL, Kass PH. The histologic and epidemiologic bases for prognostic considerations in canine melanocytic neoplasia. Veterinary Pathology 2006; 43: 136–149. 8. Grahn BH, Peiffer RL. Veterinary Ophthalmic Pathology. In: Veterinary Ophthalmology, I. 5 edn. (eds Gelatt KN, Gilger BC, Kern TJ) John Wiley & Sons, Inc., IA, USA, 2013, 435–523. 9. Wilcock B, Dubielzig RR, Render JA, editors. Histological Classification of Ocular and Otic Tumors of Domestic Animals. Armed Forces Institute of Pathology, American Registry of Pathology, Washington, DC, 2002. 10. Fischer CA, Lindley DM, Carlton WC, Van Hecke H. Tumors of the Cornea and Sclera. In: Ocular Tumors in Animals and Humans. (eds Peiffer RL, Simons KB) Iowa State Press, Ames, IA, 2002, 149–202. 11. Yan J, Qiu H, Li Y. Clinicopathological analysis of 39 patients with corneal tumor. Eye Science 2011; 26: 148–153. 12. Utman SA, James JN, Ramsden KL et al. Invasive malignant melanoma of the cornea after industrial injury. International Ophthalmology 2014; 34: 289–291.
© 2014 American College of Veterinary Ophthalmologists, Veterinary Ophthalmology, 18, 429–432
432 bauer, leis and sayi 13. Ucakhan-Gunduz O, Gunduz K, Karsloglu MZ et al. Corneal melanoma: report of three cases. Eye Contact Lens 2012; 38: 341– 344. 14. Jukic T, Katusic D, Kordic R et al. Malignant melanoma of the cornea after blunt trauma]. Ophthalmologe 2009; 106: 625–627. 15. Romaniuk W, Koziol H, Muskalski K et al. A unique case of primary corneal melanoma. Japanese Journal of Ophthalmology 2002; 46: 114–116. 16. Ward DA, Latimer KS, Askren RM. Squamous cell carcinoma of the corneoscleral limbus in a dog. Journal of the American Veterinary Medical Association 1992; 200: 1503–1506. 17. Kim MS, Kweon DH, Yi NY et al. Corneal papilloma in a dog. Veterinary Record 2005; 156: 454. 18. Esplin DG. Survival of dogs following surgical excision of histologically well-differentiated melanocytic neoplasms of the mucous membranes of the lips and oral cavity. Veterinary Pathology 2008; 45: 889–896. 19. Smedley RC, Spangler WL, Esplin DG et al. Prognostic markers for canine melanocytic neoplasms: a comparative review of the
20.
21.
22. 23.
24.
literature and goals for future investigation. Veterinary Pathology 2011; 48: 54–72. Dubielzig RR, Ketring KL, McLellan GJ et al. Veterinary Ocular Pathology - A Comparative Review, 1st edn. Sauders, Elsevier, Edinburgh, 2010. Collins BK, Collier LL, Miller MA et al. Biologic behaviour and histologic characteristics of canine conjunctival melanoma. Progress in Veterinary and Comparative Ophthalmology 1993; 3: 135–140. Gross T, PJ I, EJ W. Skin Diseases of the Dog and Cat, 2 edn. Blackwell Science, Ames, IA, 2005. Tuomaala S, Aine E, Saari KM et al. Corneally displaced malignant conjunctival melanomas. Ophthalmology 2002; 109: 914–919. McCracken JS, Klintworth GK. Ultrastructural observations on experimentally produced melanin pigmentation of the corneal epithelium. American Journal of Pathology 1976; 85: 167–182.
© 2014 American College of Veterinary Ophthalmologists, Veterinary Ophthalmology, 18, 429–432
DOI:10.1111/vop.12223
CASE REPORT
Primary corneal melanocytoma in a Collie Bianca Bauer,* Marina L. Leis* and Soraya Sayi† *Departments of Small Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada; and †Prairie Diagnostic Services, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
Address communications to: B. Bauer Tel.: (306) 966-7083 Fax: (306) 966-7174 e-mail: [email protected]
Abstract A 6-year-old female, spayed Collie was referred to the Western College of Veterinary Medicine for a 12-month history of a progressive right corneal mass. A superficial keratectomy was performed and histopathology revealed a corneal melanocytoma with complete excision. There has been no recurrence of the neoplasm to date (12 months). This is the first known report of an isolated corneal melanocytoma in a canine. Key Words: canine, cornea, eye, histopathology, keratectomy, melanocytoma
INTRODUCTION
Primary corneal neoplasia is rare.1,2 Reports of canine corneal neoplasia include papilloma,3 limbal melanocytoma,4 squamous cell carcinoma,5 hemangiosarcoma,6 and lymphoma.1 Of all the corneal neoplasias, canine limbal melanocytomas are more frequently reported and typically appear as well circumscribed, heavily pigmented, raised masses which invade the adjacent cornea, conjunctiva, and sclera.4 To the authors’ knowledge, primary, central corneal malignant melanoma, or melanocytoma have not been reported in the dog. Malignant melanomas or melanocytomas originate from the transformation of melanocytes. This neoplasm arises from varying sites within the body and has extremely diverse biologic behaviors depending on size, stage, site, and histologic parameters.7 Reported ocular neoplasia of melanocytic origin include eyelid, conjunctival, limbal, and uveal malignant melanomas and melanocytomas.8 We report a case of an isolated corneal melanocytoma that was surgically resected with no recurrence to date. CASE REPORT
Clinical history A 6-year-old female, spayed Collie was referred to the Western College of Veterinary Medicine’s Veterinary Medical Centre for evaluation of a right corneal lesion. The corneal lesion had been present for at least 12 months according to the owner and was apparently growing slowly. The dog was predominantly housed outdoors and there was no previous history of trauma to the eye. Neuro-ophthalmic examination was within normal © 2014 American College of Veterinary Ophthalmologists
limits. Schirmer tear tests were 22 and 15 mm/min in the right and left eyes, respectively, and intraocular pressures with rebound tonometry were 12 and 13 mmHg in the right and left eyes, respectively. Biomicroscopic examination of the right eye revealed an exophytic irregular black corneal mass approximately 10 mm in diameter. This mass was noted to occupy approximately 40% of the central cornea and was protruding approximately 13 mm beyond the corneal surface. Surrounding this lesion was an approximately 4 mm area of white corneal opacification, most consistent with lipid (Fig. 1). The peripheral cornea was within normal limits 360 degrees other than the presence of superficial corneal vascularization extending toward this lesion at the 10:00 position. Fundic examination revealed mild choroidal hypoplasia temporally bilaterally with the remainder of the ophthalmic examination being within normal limits. A preliminary diagnosis of a corneal neoplasm was made. Possible differential diagnoses for the corneal mass included papilloma, pigmented squamous cell carcinoma, malignant melanoma, or melanocytoma. A superficial keratectomy was recommended and was performed.
Surgical procedure The dog was anesthetized and the eye was routinely prepared for surgery with dilute povidone iodine. The lesion was delineated with a 450-micron restricted entry blade, and a lamellar keratectomy was performed with the aid of an operating microscope. The lesion was excised in one piece without touching the tumor itself (no-touch technique) with a clear circumferential corneal margin of approximately 2 mm. The excised mass was placed in 10% neutral buffered formalin and submitted to Prairie
430 bauer, leis and sayi
Figure 1. Clinical picture of the right eye demonstrating the exophytic irregular black corneal mass with surrounding corneal degeneration.
Diagnostic Services for histological evaluation. Recovery from anesthesia was uneventful and the patient was discharged from the hospital with topical ciprofloxacin and diclofenac four times daily and atropine once daily for the right eye for 14 days.
Histopathology Tissues were processed routinely for histology. Paraffin embedded sections were cut at 4 lm and stained with hematoxylin and eosin (H&E). Further sections were ‘bleached’ with 1% aqueous potassium permanganate. Histologically, the corneal mass was well circumscribed, nonencapsulated, and composed of heavily pigmented neoplastic melanocytes which were arranged in sheets, nests, and packets separated by small amounts of a fibrous stroma. The cell details were obscured by abundant dark brown to black cytoplasmic pigment (melanin) (Fig. 2). Corneal neovascularization was noted within the superfi-
Figure 2. Hematoxylin and eosin stained section of the corneal mass (409). The cells contained abundant melanin pigment.
Figure 3. Bleached section of the corneal mass (409). Neoplastic cells were large and round to polygonal.
cial corneal stroma. In the bleached sections where cell detail was evident, neoplastic cells were large and round to polygonal with distinct cell borders and contained abundant foamy cytoplasm (Fig. 3). The nuclei were round to ovoid with stippled chromatin and variably distinct nucleoli. The mitotic activity was low (3 mitosis in 10 HPF) is the best indicator of malignancy. These criteria may also be useful for ocular melanocytic neoplasia.18,19 The classification and behavior of the various canine melanocytic tumors are also influenced by anatomic location.7,9 Although canine ocular melanocytic tumors may share a similar cytological and histological appearance, the biolog-
ical behaviors and appropriate therapies can vary based on anatomic site. For example, melanocytic tumors arising from the canine conjunctiva are typically malignant due to a high degree of local invasiveness and metastatic propensity9,20,21, yet melanocytic tumors arising from the haired skin of the canine eyelid are typically behaviorally benign.9,22 Despite malignant characteristics of some human corneal tumors, distant metastasis is seldom observed11,13 and it has been suggested that isolated malignant corneal melanoma cannot metastasize due to the lack of corneal lymphatics.23 The histologic appearance of this canine melanocytic tumor and the lack of tumor recurrence 12 months following keratectomy support a benign behavior. The corneal pigmentation observed upon follow-up examination is attributed to wound-healing24; however, the case will continue to be monitored long-term for mass recurrence. REFERENCES 1. Ledbetter EC, Gilger BC. Diseases and Surgery of the Canine Cornea and Sclera. In: Veterinary Ophthalmology, 2. 5th edn. (eds Gelatt KN, Gilger BC, Kern TJ) John WIley & Sons Inc., Ames, IA, USA, 2013; 976–1049. 2. Wilcock B. The eye and ear. In: Pathology of Domestic Animals, 1. 4th edn. (eds Jubb KVF, Kennedy PC, Palmer NC) Academic Press, San Diego, CA, 1993; 441–529. 3. Bernays ME, Flemming D, Peiffer RL Jr. Primary corneal papilloma and squamous cell carcinoma associated with pigmentary keratitis in four dogs. Journal of the American Veterinary Medical Association 1999; 214: 215–217, 04. 4. Donaldson D, Sansom J, Scase T et al. Canine limbal melanoma: 30 cases (1992-2004). Part 1. Signalment, clinical and histological features and pedigree analysis. Veterinary Ophthalmology 2006; 9: 115–119. 5. Dreyfus J, Schobert CS, Dubielzig RR. Superficial corneal squamous cell carcinoma occurring in dogs with chronic keratitis. Veterinary Ophthalmology 2011; 14: 161–168. 6. Haeussler DJ Jr., Rodriguez LM, Wilkie DA et al. Primary central corneal hemangiosarcoma in a dog. Veterinary Ophthalmology 2011; 14: 133–136. 7. Spangler WL, Kass PH. The histologic and epidemiologic bases for prognostic considerations in canine melanocytic neoplasia. Veterinary Pathology 2006; 43: 136–149. 8. Grahn BH, Peiffer RL. Veterinary Ophthalmic Pathology. In: Veterinary Ophthalmology, I. 5 edn. (eds Gelatt KN, Gilger BC, Kern TJ) John Wiley & Sons, Inc., IA, USA, 2013, 435–523. 9. Wilcock B, Dubielzig RR, Render JA, editors. Histological Classification of Ocular and Otic Tumors of Domestic Animals. Armed Forces Institute of Pathology, American Registry of Pathology, Washington, DC, 2002. 10. Fischer CA, Lindley DM, Carlton WC, Van Hecke H. Tumors of the Cornea and Sclera. In: Ocular Tumors in Animals and Humans. (eds Peiffer RL, Simons KB) Iowa State Press, Ames, IA, 2002, 149–202. 11. Yan J, Qiu H, Li Y. Clinicopathological analysis of 39 patients with corneal tumor. Eye Science 2011; 26: 148–153. 12. Utman SA, James JN, Ramsden KL et al. Invasive malignant melanoma of the cornea after industrial injury. International Ophthalmology 2014; 34: 289–291.
© 2014 American College of Veterinary Ophthalmologists, Veterinary Ophthalmology, 18, 429–432
432 bauer, leis and sayi 13. Ucakhan-Gunduz O, Gunduz K, Karsloglu MZ et al. Corneal melanoma: report of three cases. Eye Contact Lens 2012; 38: 341– 344. 14. Jukic T, Katusic D, Kordic R et al. Malignant melanoma of the cornea after blunt trauma]. Ophthalmologe 2009; 106: 625–627. 15. Romaniuk W, Koziol H, Muskalski K et al. A unique case of primary corneal melanoma. Japanese Journal of Ophthalmology 2002; 46: 114–116. 16. Ward DA, Latimer KS, Askren RM. Squamous cell carcinoma of the corneoscleral limbus in a dog. Journal of the American Veterinary Medical Association 1992; 200: 1503–1506. 17. Kim MS, Kweon DH, Yi NY et al. Corneal papilloma in a dog. Veterinary Record 2005; 156: 454. 18. Esplin DG. Survival of dogs following surgical excision of histologically well-differentiated melanocytic neoplasms of the mucous membranes of the lips and oral cavity. Veterinary Pathology 2008; 45: 889–896. 19. Smedley RC, Spangler WL, Esplin DG et al. Prognostic markers for canine melanocytic neoplasms: a comparative review of the
20.
21.
22. 23.
24.
literature and goals for future investigation. Veterinary Pathology 2011; 48: 54–72. Dubielzig RR, Ketring KL, McLellan GJ et al. Veterinary Ocular Pathology - A Comparative Review, 1st edn. Sauders, Elsevier, Edinburgh, 2010. Collins BK, Collier LL, Miller MA et al. Biologic behaviour and histologic characteristics of canine conjunctival melanoma. Progress in Veterinary and Comparative Ophthalmology 1993; 3: 135–140. Gross T, PJ I, EJ W. Skin Diseases of the Dog and Cat, 2 edn. Blackwell Science, Ames, IA, 2005. Tuomaala S, Aine E, Saari KM et al. Corneally displaced malignant conjunctival melanomas. Ophthalmology 2002; 109: 914–919. McCracken JS, Klintworth GK. Ultrastructural observations on experimentally produced melanin pigmentation of the corneal epithelium. American Journal of Pathology 1976; 85: 167–182.
© 2014 American College of Veterinary Ophthalmologists, Veterinary Ophthalmology, 18, 429–432
