RESUMO
Colonization of the colon and rectum by intestinal spirochetes is detected for the first time in Brazil in 4 of 282 (1.41%) patients who had undergone sigmoidoscopy and/or colonoscopy with a histopathological diagnosis of chronic non specific-colitis. This frequency is probably underestimated, since surgically obtained specimens were not considered in the present study. Histopathological diagnosis was performed using routine stains like hematoxylin-eosin which showed the typical, of 3-microns thick hematoxyphilic fringe on the brush border of the surface epithelium, and by silver stains like the Warthin-Starry stain. Immunohistochemical procedures using two, polyclonal, primary antibodies, one against Treponema pallidum and the other against Leptospira interrogans serovar copenhageni serogroup Icterohaemorrhagiae cross-reacted with spirochetal antigen/s producing a marked contrast of the fringe over the colonic epithelium, preserving the spiral-shaped morphology of the parasite. In one case with marked diarrhea, immunohistochemistry detected spirochetal antigen/s within a cell in an intestinal crypt, thus demonstrating that the infection can be more widely disseminated than suspected using routine stains. Immunohistochemical procedures, thus, greatly facilitate the histological diagnosis of intestinal spirochetosis and may contribute to a better understanding of the pathogenesis of the disease. Transmission and scanning electron microscopy performed in one case showed that the spirochete closely resembled the species designated as Brachyspira aalborgi.
Assuntos
Colo/ultraestrutura , Doenças do Colo/patologia , Reto/ultraestrutura , Infecções por Spirochaetales/diagnóstico , Spirochaetales/ultraestrutura , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Biópsia , Brasil/epidemiologia , Criança , Pré-Escolar , Colo/microbiologia , Doenças do Colo/microbiologia , Feminino , Humanos , Imuno-Histoquímica , Lactente , Mucosa Intestinal/microbiologia , Mucosa Intestinal/ultraestrutura , Masculino , Microscopia Eletrônica , Microscopia Eletrônica de Varredura , Pessoa de Meia-Idade , Reto/microbiologia , Infecções por Spirochaetales/epidemiologia , Infecções por Spirochaetales/microbiologiaRESUMO
Colorectal cancer (CRC) is one of the most frequent cancers worldwide. Adenoma is the main precursor lesion and, recently, the serrated polyps were described as a group of colorectal lesions with malignant potential. The morphologic and biologic characterizations of serrated polyps remain limited. The aim of the present study was to determine the frequency of KRAS and BRAF mutations and microsatellite instability (MSI) in CRC precursor lesions, to evaluate the association between molecular, pathologic and morphologic alterations in precursor lesions and to compare with the alterations detected in CRC. A series of 342 precursor lesions were removed from 155 patients during colonoscopy. After morphologic classification, molecular analysis was performed in 103 precursor lesions, and their genetic profile compared with 47 sporadic CRCs. Adenomas were the main precursor lesions (70.2%). Among the serrated polyps, the main precursor lesion was hyperplastic polyps (HPs) (82.4%), followed by sessile serrated adenomas (12.7%) and traditional serrated adenomas (2.0%). KRAS mutations were detected in 13.6% of the precursor lesions, namely in adenomas and in HPs, but in no serrated adenoma. BRAF mutations were found in 9 (8.7%) precursor lesions, mainly associated with serrated polyps and absent in adenomas (P<0.001). High MSI (MSI-H) was absent in precursor lesions. In the 47 CCR cases, 46.8% exhibited KRAS mutation, 6.5% BRAF mutations and 10.6% MSI-H. This study confirms the role of KRAS and BRAF mutations in CRC carcinogenesis, a crucial step in implementing CRC screening strategies.
Assuntos
Adenocarcinoma/genética , Adenoma/genética , Pólipos do Colo/genética , Neoplasias Colorretais/genética , Instabilidade de Microssatélites , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas Proto-Oncogênicas/genética , Proteínas ras/genética , Adenocarcinoma/patologia , Adenoma/patologia , Idoso , Idoso de 80 Anos ou mais , Pólipos do Colo/patologia , Colonoscopia , Neoplasias Colorretais/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mutação , Proteínas Proto-Oncogênicas p21(ras)RESUMO
A colonizacao do colo e reto por espiroquetas intestinais foi detectada pela primeira vez no Brasil em 4 de 282 (1,41 por cento) pacientes submetidos a sigmoidoscopia e/ou colonoscopia com o diagnostico histopatologico de colite cronica inespecifica. A frequencia e provavelmente menor que a real, uma vez que especimens cirurgicos nao foram considerados no presente estudo. O diagnostico histopatologico foi feito atraves de coloracoes de rotina, tais como a hematoxilina-eosina, que mostraram franja basofilica de 3u de espessura sobre a borda em escova do epitelio e por impregnacoes pela prata como o metodo de Whartin-Starry. Metodos imunohistoquimicos, usando dois soros primarios policlonais, um contra o Treponema pallidum e outro contra Leptospira interrogans, serovar copenhageni serogrupo...