Leucemia de mastocitos, mastocitose sistêmica e mastocitoma em cães: relato de dois casos

Mast cell leukemia is a rare evolution from systemic mastocytosis. Unspecific clinical signs and neoplastic cell infiltration on the bone marrow due multiple organs involvement hypothesis leads to complications at the diagnosis. Mast cells are hematopoietic cells spread along conjunctive tissue principally in external antigens first contact organs being abnormal found on peripheral blood. Mast cell proliferative disturbs include mast cell tumor, systemic mastocytosis and mast cell leukemia. The present work aims to report tow cases of canine mast cell leukemia. Dog 1 presents at inguinal region a cutaneous mass classified as mast cell tumor grade II and Dog 2 presents enlarged mesenteric lymph nodes at ultrasound images, later classified as grade III mast cell tumor. Both animals presents on hematologic exam: anemia discrete and moderate, Dog 1 and 2 respectively, leukocytosis, neutrophilia, neutrophil hyper segmentation, monocytosis and mastocytosis. At peritoneal fluid analysis were observed physic-chemical characteristics from modified transudate and prevalence of mast cell with neoplastic characteristics being classified as neoplastic effusion. At bone marrow evaluation showed intense mast cells proliferation corresponding to 53.9% and 58% from marrow total cells in to Dog 1 and 2, respectively. Any dog presents relevant serum biochemistry alterations. Mast cell tumor metastasis on spleen, liver, lymph nodes and bone marrow from both dogs were confirmed through histopathology and immunohistochemistry exam. Both dogs were diagnosed mast cell leukemia through cytological exam from blood, cavity effusion and bone marrow. Because of the worse level of undifferentiation and great amount of metastasis neoplastic process are more resistant to chemotherapy and with the higher levels of recidivism due that the prognostic are unfavorable.