HISTIOCYTIC SARCOMA IN DOGS: TWO CASES REPORTS.

Abstract

Histiocytic sarcoma (HS) is a rare malignant neoplasm originating from dendritic cells which, for this reason, can develop in almost all tissues in a localized or disseminated manner. Clinical signs vary according to the organs affected and are generally nonspecific. In addition to presenting a ferocious and aggressive course, it is poorly responsive to chemotherapy treatments, being considered fatal after lymph node involvement. This study aimed to report two cases of disseminated histiocytic sarcoma in dogs treated at the Veterinary Hospital of the Federal University of Mato Grosso do Sul (HV-UFMS). The first animal, a three-year-old female Labrador, had pronounced abdominal distension and progressive weight loss, in addition to cachexia, dyspnea and peripheral lymphadenomegaly. Hematological, radiographic and cytological exams were performed and showed changes such as lymphopenia and neutrophil toxicity, the biochemical analysis revealed mild hyperalbuminemia. Radiographic examination changes compatible with metastasis. The dog died 20 days after the initial consultation and was referred for necropsy, which determined the diagnosis of HS through the observation of characteristic neoplastic cells in the liver, lung and renal cortex. The corpse of the second patient, a mixed-race female, was received by the pathological anatomy department with a history of increased abdominal volume, anorexia, weight loss and dyspnea. The necropsy revealed involvement of the spleen, liver, mediastinal and hepatic lymph nodes, intestine, mesentery, stomach, bladder and kidneys. Due to its aggressive character and comprehensive signs, this type of neoplasm should be considered as a differential diagnosis in order to establish palliative treatment that increases the patient's survival time.