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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
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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: • Pigmentation • Intra- and subepithelial packeting • Criteria of malignancy • Cell type(s) • Mitotic index • Necrosis • Epithelial dysplasia
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
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)
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 metastasized • One 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 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
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?
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