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Year 2012 - Volume 32, Number 4
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Amelanotic melanoma in dogs: A retrospective study of 35 cases (2004-2010) and immunohistochemical characterization, 32(4):340-346
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ABSTRACT.- Rolim V.M., Casagrande R.A., Watanabe T.T., Wouters A.T., Wouters F., Sonne L. & Driemeier D. 2012. [Amelanotic melanoma in dogs: A retrospective study of 35 cases (2004-2010) and immunohistochemical characterization.] Melanoma amelanótico em cães: estudo retrospectivo de 35 casos (2004-2010) e caracterização imuno-histoquímica. Pesquisa Veterinária Brasileira 32(4):340-346. Setor de Patologia Veterinária, Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9090, Porto Alegre, RS 91540-000, Brazil. E-mail: davetpat@ufrgs.br
Melanomas are aggressive tumors of melanocytes. They are common in dogs and involve mainly the oral cavity, mucocutaneous junction, and skin. Furthermore, these tumors could be highly pigmented or lack pigment. The biopsies archives from SPV-UFRGS, 2004 to 2010, were retrieved and melanocytic neoplasms in dogs were revised. A retrospective study of 35 cases of amelanotic melanomas (AM) was performed, also immunohistochemistry (IHC) characterization was evaluated. The dogs more affected were mixed breed followed by Poodle, Dachshund and Cocker Spaniel. The average age of the dogs was 10.7 years (5-18 years in age) and there was no sex predilection. The locations of the neoplasms were the oral cavity (57.1%) and digits (17.1%). Histologically, 40% were classified as epithelioid, 34.3% mixed and 25.7% spindle. The positive immunostaining for vimentin, S-100 protein and melan-A were 86.6%, 70%, and 56.6% respectively. These results indicated the most affected dogs with AM were elderly. Epiteliod classification was the most observed histologically. It is important to perform IHC, due to lacking of differentiation of AM, mainly, anti S-100 protein that showed to be the best option of positive marker, even better to Melan-A. |
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