Differential diagnosis of canine gastrointestinal stromal tumor / Diagnóstico diferencial de tumor estromal gastrointestinal canino

ABSTRACT

Background: Stromal Grastrointestinal Tumors (GIST) are rare mesenchymal neoplasms that affect the wall of the gastrointestinal tract (GIT). Histologically this tumor shows a spindle, epithelioid or mixed aspect and routine hematoxylin and eosin (HE) staining does not allow adequate differentiation from other mesenquimal neoplasms. Histochemical and imunohistochemical techniques are useful tools in this differentiation. The aim of this study was to report a case of canine GIST, emphasizing the use of histochemical and immunohistochemical techniques to differentiate it from other histomorfologically similar mesenchymal neoplasms.Case A ten-year-old male Pinscher dog was submitted to surgical excision of a tumor in the pyloric region of stomach. The dog was euthanized 90 days after surgery. Tumor specimens were collected, fi xed in 10% neutral buffered formalin solution and embedded in paraffi n. Afterwards, 4 µm histological sections were obtained and stained with HE and Gomoris Tricrome (GT). For immunohistochemical analysis a biotin-peroxidase system was used and secondary antibodies were identifi ed using Advance HRP. Cytokeratin (CK) AE1/AE3, c-KIT, vimentin, Ki-67, S-100 and Smooth Muscle Alfa Actin (SMA) expression were evaluated. For vimentin, CKAE1AE3, SMA, S100 and c-KIT antibodies, a semiquantitative method was used and neoplasms were classifi ed as negative (-), pos

RESUMO

Background: Stromal Grastrointestinal Tumors (GIST) are rare mesenchymal neoplasms that affect the wall of the gastrointestinal tract (GIT). Histologically this tumor shows a spindle, epithelioid or mixed aspect and routine hematoxylin and eosin (HE) staining does not allow adequate differentiation from other mesenquimal neoplasms. Histochemical and imunohistochemical techniques are useful tools in this differentiation. The aim of this study was to report a case of canine GIST, emphasizing the use of histochemical and immunohistochemical techniques to differentiate it from other histomorfologically similar mesenchymal neoplasms.Case A ten-year-old male Pinscher dog was submitted to surgical excision of a tumor in the pyloric region of stomach. The dog was euthanized 90 days after surgery. Tumor specimens were collected, fi xed in 10% neutral buffered formalin solution and embedded in paraffi n. Afterwards, 4 µm histological sections were obtained and stained with HE and Gomoris Tricrome (GT). For immunohistochemical analysis a biotin-peroxidase system was used and secondary antibodies were identifi ed using Advance HRP. Cytokeratin (CK) AE1/AE3, c-KIT, vimentin, Ki-67, S-100 and Smooth Muscle Alfa Actin (SMA) expression were evaluated. For vimentin, CKAE1AE3, SMA, S100 and c-KIT antibodies, a semiquantitative method was used and neoplasms were classifi ed as negative (-), pos