RESUMO
Intravascular lymphoma is characterized by being a malignant neoplasm of extranodal T or B lymphocytes with exclusive proliferation within the vascular lumen, particularly of small vessels. The clinical signs vary due to the involvement of several organs, mainly the central nervous system. The diagnosis is difficult because many of the tests performed are not conclusive and, therefore, necropsy is the most efficient way to identify this tumor. This case report aims to describe the anatomopathological findings of a case of intravascular lymphoma in a mixed breed, 8 years old dog who presented neurological signs and was submitted to a necroscopic examination with clinical suspicion of granulomatous meningoencephalitis. The necropsy findings were not specific, but the presence of intravascular neoplastic lymphocytes int he brain, spleen, adrenal gland and stomach was verified by microscopy. These cells were positive for the CD3 antibody by immunohistochemistry, confirming the T lymphocyte phenotype. This neoplasm should be considered in the diagnosis of encephalopathies in dogs.
Assuntos
Masculino , Animais , Cães , Linfoma/diagnóstico por imagem , Linfoma/patologia , Linfócitos/patologia , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/patologia , Neoplasias Vasculares/diagnóstico por imagem , Neoplasias Vasculares/patologia , Doenças do Cão/patologia , Linfoma/veterinária , Neoplasias Encefálicas/veterinária , Neoplasias Vasculares/veterináriaRESUMO
Intravascular lymphoma is characterized by being a malignant neoplasm of extranodal T or B lymphocytes with exclusive proliferation within the vascular lumen, particularly of small vessels. The clinical signs vary due to the involvement of several organs, mainly the central nervous system. The diagnosis is difficult because many of the tests performed are not conclusive and, therefore, necropsy is the most efficient way to identify this tumor. This case report aims to describe the anatomopathological findings of a case of intravascular lymphoma in a mixed breed, 8 years old dog who presented neurological signs and was submitted to a necroscopic examination with clinical suspicion of granulomatous meningoencephalitis. The necropsy findings were not specific, but the presence of intravascular neoplastic lymphocytes int he brain, spleen, adrenal gland and stomach was verified by microscopy. These cells were positive for the CD3 antibody by immunohistochemistry, confirming the T lymphocyte phenotype. This neoplasm should be considered in the diagnosis of encephalopathies in dogs.(AU)
Assuntos
Animais , Masculino , Cães , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/patologia , Linfócitos/patologia , Linfoma/diagnóstico por imagem , Linfoma/patologia , Neoplasias Vasculares/diagnóstico por imagem , Neoplasias Vasculares/patologia , Neoplasias Encefálicas/veterinária , Doenças do Cão/patologia , Linfoma/veterinária , Neoplasias Vasculares/veterináriaRESUMO
Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine that is produced by many cell types in situations of homeostasis or disease. One of its functions is to act as a proinflammatory molecule. In humans, several studies have shown that MIF levels become elevated in the serum, urine, cerebrospinal fluid and tissues of patients with chronic inflammatory diseases (systemic lupus erythematosus, rheumatoid arthritis, multiple sclerosis, sepsis, atheromas, diabetes and cancer). In dogs, distemper is a viral infectious condition that may lead to demyelination and inflammation in the central nervous system (CNS). In addition to the action of the virus, the inflammatory process may give rise to lesions in the white matter. Therefore, the objectives of the present study were to evaluate the role of MIF in the encephalitis that the canine distemper virus causes and to compare this with immunodetection of major histocompatibility complex-II (MHC-II), CD3 T lymphocytes, MMP-9 and glial fibrillary acidic protein (GFAP; astrocytes) in demyelinated areas of the encephalon, in order to ascertain whether these findings might be related to the severity of the encephalic lesions. To this end, a retrospective study on archived paraffinized blocks was conducted, in which 21 encephala from dogs that had been naturally infected with the canine distemper virus (infected group) and five from dogs that had been free from systemic or CNS-affecting diseases (control group) were used. In the immunohistochemical analysis on the samples, the degree of marking by GFAP, MHC-II, MMP-9 and MIF was greater in the demyelinated areas and in the adjacent neuropil, and this was seen particularly in astrocytes. Detection of CD3 was limited to perivascular cuffs. In areas of liquefactive necrosis, Gitter cells were positive for MMP-9, MIF and MHC-II. Hence, it was concluded that activated astrocytes influenced the afflux of T lymphocytes to the encephalon (encephalitis). In the more advanced phases, activated phagocytes in the areas of liquefactive necrosis (Gitter cells) continued to produce inflammatory mediators even after the astrocytes in these localities had died, thereby worsening the encephalic lesions. Distemper virus-activated astrocytes and microglia produce MIF that results in proinflammatory stimulus on glial cells and brain-infiltrating leukocytes. Therefore, the effect of the inflammatory response is potentiated on the neuropil, resulting in neurological clinical signs.