RESUMO: Neoplasias mamárias caninas com componentes mesenquimais malignos, como carcinossarcomas e sarcomas, são um grupo de neoplasias pouco frequentes e histologicamente heterogêneas e pouco se sabe sobre o comportamento biológico das variantes histogênicas. O objetivo desse estudo é comparar as características anatomopatológicas e a expressão imunoistoquímica de COX-2 de diferentes subtipos histológicos de carcinossarcomas e sarcomas. Foram estudados 23 carcinosarcomas e 17 sarcomas da glândula mamária de cadelas. Os prontuários médicos foram revisados para obtenção de dados clínicos. Posteriormente, as lâminas histológicas foram avaliadas para acessar os subtipos mesenquimais, necrose, invasão vascular, grau histológico, metástase linfonodal. A imunoistoquímica foi realizada para avaliar a expressão de COX-2. Os tipos encontrados de proliferação mesenquimal maligna foram osteossarcoma (23/40), fibrossarcoma (7/40), lipossarcoma (6/40) e condrossarcoma (4/40). A diferenciação osteossarcomatosa foi predominante entre os sarcomas e carcinossarcomas e foi associado com invasão vascular (P=0,006) e metástase linfonodal (P=0,014). Uma expressão alta de COX-2 foi detectada em 14,3% dos carcinossarcomas (células carcinomatosas e/ou sarcomatosas) e 27,3% dos sarcomas. Os carcinossarcomas e sarcomas apresentaram características clínicas e patológicas semelhantes e se desenvolveram como tumores grandes, com necrose intratumoral e predomínio de alto grau histológico, mas com baixa frequência de invasão vascular e metástase distante. Os subtipos osteossarcomatosos apresentaram características mais agressivas quando comparados com subtipos não osteossarcomatosos. RESUMO malignos histogênicas COX2 COX 2 COX- 1 cadelas clínicos Posteriormente histológico COX2. 2. 23/40, 2340 23/40 , 40 (23/40) 7/40, 740 7/40 7 (7/40) 6/40 640 6 (6/40 4/40. 440 4/40 . 4 (4/40) P=0,006 P0006 P 0 006 (P=0,006 P=0,014. P0014 P=0,014 014 (P=0,014) 143 14 3 14,3 células eou ou sarcomatosas 273 27 27,3 grandes distante 234 23/4 (23/40 74 7/4 (7/40 6/4 64 (6/4 44 4/4 (4/40 P=0,00 P000 00 (P=0,00 P001 P=0,01 01 (P=0,014 14, 27, 23/ (23/4 7/ (7/4 6/ (6/ 4/ (4/4 P=0,0 P00 (P=0,0 (P=0,01 (23/ (7/ (6 (4/ P=0, P0 (P=0, (23 (7 ( (4 P=0 (P=0 (2 P= (P= (P
ABSTRACT: Canine mammary neoplasms with malignant mesenchymal components, such as carcinosarcomas and sarcomas, belong to an uncommon and histologically heterogeneous group. Little is known about the biological behavior of these histogenic variants. This study aimed to compare the clinicopathological characteristics and the COX-2 immunohistochemical expression of different histologic subtypes of carcinosarcomas and sarcomas. Samples of 23 carcinosarcomas and 15 sarcomas from the mammary glands of female dogs were studied. Medical records were reviewed to obtain clinical data. Subsequently, histology microscope slides were analyzed to assess for mesenchymal subtypes, necrosis, vascular invasion, histologic grades, and lymph node metastasis. Immunohistochemistry was used to assess the COX-2 expression. The malignant mesenchymal proliferation was categorized into osteosarcomas (23/40), fibrosarcomas (5/40), liposarcomas (6/40) and chondrosarcomas (4/40). The osteosarcomatous differentiation was the most predominant type among the sarcomas and carcinosarcomas and was associated with vascular invasion (P=0.010) and lymph node metastases (P=0.014). High COX-2 expression was detected in 14.3% of the carcinosarcomas (carcinoma and/or sarcoma cells) and 27.3% of the sarcomas. The carcinosarcomas and sarcomas had similar clinical and pathological characteristics and developed as large tumors, with intratumoral necrosis and a predominance of high histologic grades, although the frequency of vascular invasion and lymph node metastasis was low. Osteosarcoma subtypes presented more aggressive characteristics than non-osteosarcoma subtypes. ABSTRACT components group variants COX2 COX 2 COX- 1 studied data Subsequently grades 23/40, 2340 23/40 , 40 (23/40) 5/40, 540 5/40 5 (5/40) 6/40 640 6 (6/40 4/40. 440 4/40 . 4 (4/40) P=0.010 P0010 P 0 010 (P=0.010 P=0.014. P0014 P=0.014 014 (P=0.014) 143 14 3 14.3 carcinoma andor or cells 273 27 27.3 tumors low nonosteosarcoma non osteosarcoma 234 23/4 (23/40 54 5/4 (5/40 6/4 64 (6/4 44 4/4 (4/40 P=0.01 P001 01 (P=0.01 (P=0.014 14. 27. 23/ (23/4 5/ (5/4 6/ (6/ 4/ (4/4 P=0.0 P00 (P=0.0 (23/ (5/ (6 (4/ P=0. P0 (P=0. (23 (5 ( (4 P=0 (P=0 (2 P= (P= (P