Relato de caso: Histiocitose reativa em um ção

Abstract

Reactive histiocytosis (RH) is part of a group of proliferative disorders of histiocytic cells, including histiocytoma, cutaneous reactive histiocytosis (CRH), systemic reactive histiocytosis (SRH), histiocytic sarcoma (HS) and hemophagocytic histiocytic sarcoma. For precise diagnosis of this diseases, besides the clinical history and cytologic or histopathologic exams, it is often necessary use immunohistochemistry (IHC). CRH and SRH, have its origin in intersticial dendritic cells CD1+, CD11c+, MHC-II+, CD4-, Thy-1 and E-cad, are rarely reported in literature. CRH is characterized by button-shape cutaneous lesions, which may extend to small plaques or ring shapes. When there is systemic involvement of mucous membranes, lymph nodes and internal organs, disease is classified as SRH. Present study related a case with clinical and cytological characteristics of RH, possibly SRH, in a female dachshund canine patient, with 12-year-old, presenting crusted lesions in neck, snout and limbs extremities, with ocular and nasal plane involvement. Fine needle aspiration of lesions was performed for cytological aspiration, where was observed intense concentration of oval cells with elongated nucleus, characteristic of histiocytic cells which, in this case, showed low pleomorphism. Associated with this cellular type, there was lymphocytes, plasma cells and neutrophils, but no other tissue cells or microorganisms were observed. Cytological evaluation, associated to clinical history of intermittent lesions, allowed the diagnostic suggestion of SRH, which was not confirmed by IHC as it is not commercially available for this disease in our country. Imaging evaluation allowed the suspicion of CRH, due to radiographic characteristics of a lung topography nodule. Treatment, initially made with corticosteroids and antibiotic therapy, did not show satisfactory results, having the prescription changed and immunosuppressive therapy with azathioprine and prednisolone was initiated, resulting in total or partial lesion remission, with improvement in patient’s general clinical condition. The aim of this study is to increase the data base in scientific literature, detailing diagnosis stage and treatment of RH in a dog, to elucidate new cases and assist cytological examination of this disease.