Histopathological and Immunohistochemical Diagnostic of Carcinosarcoma of Mandible in a Rainbowtrout (Onchorhyincus mykiss)

Acta Scientiae Veterinariae

Site: http://www.ufrgs.br/actavet/
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ISSN: 16799216
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Início Publicação: 31/12/1969
Periodicidade: Trimestral
Área de Estudo: Medicina Veterinária

Histopathological and Immunohistochemical Diagnostic of Carcinosarcoma of Mandible in a Rainbowtrout (Onchorhyincus mykiss)

Ano: 2010 | Volume: 38 | Número: 3
Autores: Luis Alberto Romano, Yara Aiko Tabata, Agar Alexandrino
Autor Correspondente: Luis Alberto Romano | [email protected]

Palavras-chave: carcinosarcoma, neoplasia, tumor, fish, rainbowtrout, mandible

Resumos Cadastrados

Resumo Inglês:

Background: The most common health problems described in fishes are noninfectious, infectious, and metabolic disorders.
Fishes have neoplasias that are similar to those observed in mammals. Though these neoplasias do not cause economic losses
to aquaculture, they have aroused a crescent interest from the comparative pathology’s point of view. Neoplasias of the oral
cavity in fishes are usually reported as individual cases, but mandible tumors are not common, and most of them are squamous
cells carcinomas. The aim of this study is to report a case of carcinosarcoma of the mandible in a rainbow trout (Oncorhynchus
mykiss), obtained from a trout farm in Campos do Jordão, São Paulo, Brazil.
Case: The fish underwent necropsy and tissue samples were collected and fixed with a buffer-neutralized formalin solution,
which were then embedded in paraffin, sectioned in 5 μm sections and stained with hematoxylin-eosin. The histological
sections were stained for immunohistochemical procedures, according to a modified avidin-biotin-peroxidase complex technique.
Slides containing tissue were deparaffinized with xylol and rehydrated with alcohol of different grades. The endogenous
peroxidase activity was blocked by incubating the slides for 20 min at 0.3% H2O2 in a solution of 5% methanol. After
rinsing the slides in water and in a PBS/0.05%-Tween 20 solution, they were incubated in normal serum diluted 1:100
containing 10% bovine albumin in PBS (BSA), at room temperature for 30 min in humid chamber. After incubation, the
primary anti-cytokeratin and anti-vimentin antibody was added to a 1:200 dilution in 10% PBS-BSA, and the slides were
incubated until the next day at 41oC in humid chamber. The slides were then rinsed in PBS and incubated for 7 min in a 50 mL
30.3-diaminobenzidine solution containing 1% PBS-BSA in 50 mL H2O2. Hematoxylin was used for counterstaining. The
immunohistochemical analysis showed a tumor with epithelial and mesenchymatous neoplastic components. The epithelial
component presented an epidermoid carcinoma with well differentiated and keratinizing areas, in addition to other little
differentiated, non-keratinizing areas. The mesenchymatous component presented a fibrosarcoma. The immunohistochemical
analysis demonstrated signs of cytokeratin in carcinomatous elements and of vimentin in sarcomatous elements.
Discussion: Fishes are valuable resources in human nutrition, medicine, science and leisure. Similarly to other poikilothermic
vertebrates, fishes also develop benign and malign neoplasias. However, it is their infectious diseases that are more known and
studied. Teleost fishes constitute the widest and most diverse class of vertebrates, with over 20,000 known species. The
diversity and placement in the phylogenetic tree make teleost fishes the ideal objects for comparative carcinogenesis studies,
which could allow a broader knowledge about basic neoplastic development mechanisms, in comparison to studies limited to
mammal models only. According to our knowledge and considering the literature available on fish tumors, this is the first
description of a carcinosarcoma of the mandible affecting a rainbow trout.