Features of Canine Conjunctival Melanocytic Tumors Reilly

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Features of Canine Conjunctival Melanocytic
Tumors

• Reilly CM, Dubielzig RR, Newman SJ and Bergman PJ

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Purposes

• A retrospective study of the histologic and
  biologic features of canine conjunctival
  melanocytic tumors
• Compare to results of prior studies
• Biologic behavior and histologic characteristics
  of canine conjunctival melanomas. Collins BK,
  Collier LL, Miller MA, Linton LL. Prog in vet and
  comparative ophthalmology 3135-140, 1993.

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Methods

• Cases of conjunctival melanocytic tumors selected
  (COPLOW and AMC)
• Follow-up surveys mailed to submitting
  ophthalmologists
• Only cases with follow-up available were included

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Methods (cont.)

• Slides were evaluated for
• Pigmentation
• Intra- and subepithelial packeting
• Criteria of malignancy
• Cell type(s)
• Mitotic index
• Necrosis
• Epithelial dysplasia

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Methods (cont.)

• Survey information included
• Breed, gender, age at diagnosis
• Tumor location (bulbar, TEL, palpebral)
• Surgery type (incisional, excisional,
  enucleation, exenteration)
• Recurrence, metastasis and death

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Results

• 63 cases were identified
• 24 had follow-up available
• 14 males, 10 females
• 8 mixed breeds, 3 labs, 2 cockers, 2 Weimaraners,
  2 Shar-peis
• 1 each Schnauzer, German Shepherd, Poodle, Golden
  Retriever, Boston Terrier, Pekingese,
  Newfoundland
• Age at diagnosis 6-14 y (11.5)

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Results Location

• 14/23 (61) on TEL
• 5/23 (22) on bulbar conjunctiva
• 4/23 (17) on palpebral conjunctiva
• Location not provided for one tumor

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Results - Histologic patterns

• 14/24 (60) had packeting of neoplastic cells
  within conj. epithelium
• 19/24 (83) had packeting in subepithelial stroma
• No correlation with recurrence or metastasis
• Can be helpful in diagnosis of amelanotic tumors

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Results Benign tumors

• 3/24 (12) histologically benign (melanocytomas)
• None had necrosis, mitoses or dysplasia
• None recurred or metastasized
• One was multicentric at diagnosis

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Results - malignant

• 17/21 (81) at least partially pigmented
• 5/21 (24) were spindle cell type
• 7/21 (33) were epithelioid type
• 9/21 (43) were a mixture of both

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Results - Recurrence

• 10/21 (48) tumors recurred
• 4/12 (33) TEL tumors
• 2/10 (20) w/ marginal excision
• 2/3 (67) w/ complete TEL excision
• 2/4 (50) bulbar tumors
• 3/4 (75) palpebral tumors
• One tumor (TEL) had multicentric recurrence

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Results Tumor related death

• Only 2 tumors (10) metastasized
• Both from palpebral conjunctiva
• 1 dog (5) euthanized for aggressive regrowth
• Also from palpebral conjunctiva
• No dogs with TEL or bulbar tumors died from tumor
• Palpebral tumors more advanced at diagnosis?

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Conclusions

• Similar to prior report EXCEPT
• Even male female ratio
• Shar-peis also over represented
• Metastatic risk may be lower (10 v. 17)
• Recurrence even with aggressive surgery
• Stresses the need for assertive follow-up
• Especially rare diseases

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Acknowledgements

• Co-authors Dr. Dick Dubielzig, Rebecca Morris,
  Dr. Shelley Newman, Dr. Phillip Bergman
• Technical Assistance Kate Leiber

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Questions?