Metastatic extramedullary plasmacytoma in a canine

Abstract

Plasmocytomas are neoplasms originating from plasma cells and can be subdivided into cutaneous extramedullary, non-cutaneous and multiple myeloma. The involvement of vertebrae can generate clinical signs of pain and neurological alterations according to the affected segment. The present study aims to report a case of extramedullary plasmacytoma in the thoracic spine and with consequent spinal cord compression in addition to metastasis sites, characterizing its clinicopathological aspects. The canine patient was hospitalized, submitted to laboratory and imaging tests, and medicated due to incoordination and loss of perception of limb positioning, but his clinical picture worsened, progressing to loss of movement and fecal and urinary incontinence, resulting in death. The main necropsy findings were the presence of a tumor mass along the external surface of the body of the fifth thoracic vertebra, in addition to light brown foci in the thoracic spinal cord and in the pulmonary and splenic parenchyma. Histologically, the tumor mass and light brown foci consisted of malignant cell proliferation, of plasmacytic origin, densely cellular and largely infiltrative. Thus, through the clinical picture presented, imaging tests and anatomopathological analysis, it was shown that it was a case of extramedullary plasmocytoma originating in the thoracic spine, with sites of metastasis in the spinal cord, lung and spleen.