Features of Canine Conjunctival Melanocytic

Tumors

Reilly CM, Dubielzig RR, Newman SJ and Bergman PJ

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; 3:135-140, 1993.

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

Methods (cont.)

Slides were evaluated for:PigmentationIntra- and subepithelial packetingCriteria of malignancyCell type(s)Mitotic indexNecrosisEpithelial dysplasia

Methods (cont.)

Survey information included:Breed, gender, age at diagnosisTumor location (bulbar, TEL,

palpebral)Surgery type (incisional, excisional,

enucleation, exenteration)Recurrence, metastasis and death

Results

63 cases were identified24 had follow-up available

14 males, 10 females8 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)

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

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

Results – Benign tumors

3/24 (12%) histologically benign (melanocytomas)

None had necrosis, mitoses or dysplasia

None recurred or metastasizedOne was multicentric at diagnosis

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

Results - Recurrence

10/21 (48%) tumors recurred4/12 (33%) TEL tumors

2/10 (20%) w/ marginal excision2/3 (67%) w/ complete TEL excision

2/4 (50%) bulbar tumors3/4 (75%) palpebral tumorsOne tumor (TEL) had multicentric

recurrence

Results – Tumor related death

Only 2 tumors (10%) metastasizedBoth from palpebral conjunctiva

1 dog (5%) euthanized for aggressive regrowthAlso from palpebral conjunctiva

No dogs with TEL or bulbar tumors died from tumorPalpebral tumors more advanced at diagnosis?

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

Acknowledgements

Co-authors: Dr. Dick Dubielzig, Rebecca Morris, Dr. Shelley Newman, Dr. Phillip Bergman

Technical Assistance: Kate Leiber

Questions?