Mixossarcoma esplênico em cão / Splenic myxosarcoma in a dog

ABSTRACT

Background: Myxosarcomas (MXS) are malignant mesenchymal neoplasms originated from mainly mucin producing fibroblasts than collagen. Despite malignant neoplasms, MXS is believed to have low metastase generation ability. Myxosarcomas reports in dogs are widespread, usually involving trunk and limbs subcutaneous tissue. The aim of this report is to describe clinical, pathological, and immunohistochemistry aspects of a rare case of splenic myxosarcoma in a dog.Case A 10-year-old, intact male Basset Hound, weiging 25 kg, showing signals such apathy, dark soft-stooled stools, progressive thinning, and increasing abdominal enlargement, perceived three months ago was brought to clinical consultation. Physical examination showed extremely pale oral and ocular mucosas, in addition to mild dehydration (6%), 35.4°C rectal temperature, and a very bulging abdomen, with no fluids or gases, evidence at abdominal percussion. A complete blood count (CBC) revealed neutrophilic leukocytosis and anemia. Patient´s abdominal cavity ultrasound examination showed an heterogeneous mass, occupying large part of cavity, and apparently from spleen origin. A spleenic multilobulated mass measuring 25 x 12 x 20 cm was obtained after exploratory laparotomy. The mass showed predominantly soft consistency with some firm areas, and no visible mesentery or other abdominal organs adhesions. Mass and spleen histopathological examination were routinely processed for histological analysis with haematoxylin and eosin and alcian blue staining. In addition, fragments of the neoplasm were submitted to immunohistochemistry (IHC) which confirmed myxosarcoma diagnosis. The owner returned to hospital two months after, complaining for apathy, prostration, anorexia, and abdominal pain. A new ultrasound examination were suggestive of liver and kidneys neoplasms. The tutor opted for patient´s euthanasia. However, dog´s necropsy was not authorized...