RESUMO
La detección de proteínas de reparación del ADN por inmunohistoquímica (IHQ) ha demostrado ser útil para determinar inestabilidad de microsatélites (IM). Las guías de Bethesda revisadas y el MsPath Score permiten detectar pacientes de alto riesgo. Se analizaron criterios histológicos sugestivos de IM en 115 pacientes con cáncer colorrectal (CCR). Se efectúo el MsPath Score e IHQ para la demostración de proteínas de reparación del ADN (MMR): MLH1 MSH2, MSH6 y PMS2. La distribución por sexos fue de 66 varones y 49 mujeres, con un rango etario de 16 a 78 años. Cincuenta y tres casos tuvieron rasgos morfológicos de IM: linfocitos intraepiteliales (n = 31), infiltrados tipo Crohn (n = 17), morfología mucinosa/células en anillo de sello (n = 32) y/o pobre diferenciación (n = 12) en forma simultánea o aisladamente. Se observó patrón aberrante para MMR en 16 casos: ausencia de expresión de MLH1/PMS2 (n = 11), MSH2/MSH6 (n = 3), MLH1 (n = 1) y PMS2 (n = 1). Los adenocarcinomas con rasgos morfológicos convencionales no mostraron alteraciones en las MMR (n = 62) (AU)
The detection of mismatch repair proteins (MMR) by immunohistochemistry (IHC) is a useful tool in the identification of microsatellital inestability (MI). The revised Bethesda guidelines and MsPath score allow the detection of patients at high-risk for MI. We studied 115 patients with colorectal cancer (CRC) and evaluated the histological criteria of MI. Detection of MMR: MLH1, MSH2, MSH6 and PMS2 were analyzed by IHC. Sixty-six male and 49 female patients (age range 16-78). Histological picture of MI was observed in 53 cases: intraepithelial lymphocytosis (n = 31), Crohn like infiltrates (n = 17), mucinous or ringed cell histology (n = 32) and/or poorly differentiated histology (n = 12). Aberrant immunostaining pattern of MMR was observed in 16 cases: negative MLH1/PMS2 (n = 11), negative MSH2/MSH6 (n = 3), negative MLH1 (n = 1) and negative PMS2 (n = 1). The 62 cases with conventional histology had normal immunostaining. Conventional histology (n = 62) did not show any alterations in MMR (AU)
Assuntos
Humanos , Masculino , Feminino , Adolescente , Adulto Jovem , Adulto , Pessoa de Meia-Idade , Neoplasias Colorretais/diagnóstico , Neoplasias Colorretais/patologia , Neoplasias Colorretais Hereditárias sem Polipose/diagnóstico , Neoplasias Colorretais Hereditárias sem Polipose/patologia , Síndrome de Lynch II/diagnóstico , Síndrome de Lynch II/patologia , Adenocarcinoma Mucinoso/diagnóstico , Adenocarcinoma Mucinoso/patologiaRESUMO
BACKGROUND: The existence of microscopic tumor implants in the rectal wall, distal to the inferior edge of macroscopic tumor in rectal cancer (RC) (either in continuity with, or discontinuously) is called distal intramural spread (DIS). PATIENTS AND METHODS: Between March 2006 and June 2008, in the Instituto de Oncología Ángel H Roffo, Universidad de Buenos Aires, the frequency and distance of DIS was studied in 21 patients undergoing surgery for RC who received neoadjuvant therapy. The study was observational, descriptive, longitudinal and prospective. RESULTS: Median age was 64 years and 66.7% ofpatients were male. Stages pre-treatment were: I in 2 patients (9.5%), II in 9 (42.8%), III in 7 (28.6%), IV in 2 (14.3%), and x in 1 (4.8%). Twenty patients received neoadjuvant combined radiotherapy plus chemotherapy modality. One patient received only radiotherapy. Pathological stages were: 0 in 1 case (4.8%), I in 3 (14.3%), II in 6 (28.6%), III in 6 (28.6%), and IV in 2 (9.5%). Three patients (14.3%) hada complete pathological response. We found DIS in only one case (4.8%) at 9 mm of the macroscopic tumor edge. CONCLUSIONS: According to our experience and as recorded in the literature, we conclude that the DIS in RC is a rare phenomenon. The minimum distal margin to preserve must be at least 10 mm in the formalin-fixed specimen.
