Salivary gland myoephitheliomas: cytological, histological, immunohistochemical and electromicroscopical studies of four cases

Se presentan los resultados multidisciplinarios de cuatro casos de mioepiteliomas de glándula salival diagnosticados por biopsia por aspiración con aguja fina y resecados posteriormente. Histológicamente dos casos fueron benignos y dos malignos. Los extendidos celulares de las variedades benignas contenían una población uniforme de células discretamente alargados con citoplasma bipolar y membranas celulares conspicuas. El núcleo fue pequeño y oval con cromatina homogénea. Las células se disponían en grupos y nidos sobre un fondo proteináceo. Se observaron células aisladas adyacentes que presentaban citoplasma eosinófilo, granular y claro con núcleo central, redondo e hipercromático. En uno de los extendidos se observó numerosos capilares con células endoteliales prominentes y fondo con matrix condroide. Dos casos presentaron cambios citológicamente malignos con un fondo necrohemorrágico, pleomorfismo, nucléolo prominente, hipercromatismo y mitosis atípicas ocasionales. Las reacciones de inmunohistoquímica demostraron positividad para proteína S-100 y vimentina y focalmente para citoqueratina. Los hallazgos de la microscopia electrónica correspondieron a células mioepiteliales.

Control de calidad interno en citología cérvico-vaginal mediante revisión rápida: evaluación de la capacidad del personal del laboratorio para utilizar el procedimiento / Rapid rescreening as internal quality control in cervical citology. Personal proficiency testing of the laboratory personnel

Entre los procedimientos de control interno de calidad para evitar falsos negativos en citología ginecológica, la segunda revisión rápida de todos los casos negativos ha demostrado su eficacia. Para poner en práctica el procedimiento, antes de utilizarlo evaluamos la capacidad del personal del laboratorio. Se estudiaron 66 casos escogidos aleatoriamente revisándose cada laminilla en un tiempo de 30, 50 segundos, utilizando el objetivo 10x; las laminillas anormales, se separaron para ser evaluadas posteriormente. Hubo tres casos anormales que correspondieron, por diagnóstico de consenso, a cambios atípicos de etiología incierta, favoreciendo una lesión escamosa intraepitelial de bajo grado. Un observador, discrepó de los resultados obtenidos por el resto del grupo, ya que sólo identificó uno de los tres caso anormales; por esta razón, nuestros valores globales promedio disminuyeron: la sensibilidad fue de 91.6 por ciento, la especificidad de 100 por ciento, el valor predictivo positivo fue de 100 por ciento y el negativo de 99.6 por ciento, la tasa global de falsos negativos subió a 8.3 por ciento. Este estudio identifica al personal del laboratorio que está capacitado para poner en práctica el procedimiento, por lo que el observador que falló en sus apreciaciones deberá tener un adiestramiento ulterior.

Epidemiology and molecular pathology of gallbladder cancer.

Gallbladder cancer is usually associated with gallstone disease, late diagnosis, unsatisfactory treatment, and poor prognosis. We report here the worldwide geographical distribution of gallbladder cancer, review the main etiologic hypotheses, and provide some comments on perspectives for prevention. The highest incidence rate of gallbladder cancer is found among populations of the Andean area, North American Indians, and Mexican Americans. Gallbladder cancer is up to three times higher among women than men in all populations. The highest incidence rates in Europe are found in Poland, the Czech Republic, and Slovakia. Incidence rates in other regions of the world are relatively low. The highest mortality rates are also reported from South America, 3.5-15.5 per 100,000 among Chilean Mapuche Indians, Bolivians, and Chilean Hispanics. Intermediate rates, 3.7 to 9.1 per 100,000, are reported from Peru, Ecuador, Colombia, and Brazil. Mortality rates are low in North America, with the exception of high rates among American Indians in New Mexico (11.3 per 100,000) and among Mexican Americans. The main associated risk factors identified so far include cholelithiasis (especially untreated chronic symptomatic gallstones), obesity, reproductive factors, chronic infections of the gallbladder, and environmental exposure to specific chemicals. These suspected factors likely represent promoters of carcinogenesis. The main limitations of epidemiologic studies on gallbladder cancer are the small sample sizes and specific problems in quantifying exposure to putative risk factors. The natural history of gallbladder disease should be characterized to support the allocation of more resources for early treatment of symptomatic gallbladder disease in high-risk populations. Secondary prevention of gallbladder cancer could be effective if supported by cost-effective studies of prophylactic cholecystectomy among asymptomatic gallstone patients in high-risk areas.

[Knowledge of health professionals about the prevention of cancer the cervix. Alternatives to medical education]. / El conocimiento de profesionales de la salud sobre la prevención del cáncer cervical. Alternativas de educación médica.

OBJECTIVE: Several studies have shown the importance of health care professionals as predictors of the use of cervical cancer screening (CCS). MATERIAL AND METHODS: A cross-sectional study of 520 health care professionals in the State of Morelos during 1998, in order to evaluate and quantify their level of knowledge on the impact, etiology, screening, diagnosis and treatment of cervical cancer. A 1 to 10 scale questionnaire was given, and the sample included family medicine specialists, general practitioners, specialist and general nurses, and social workers. Statistical analysis included analysis of variance and 95% confidence intervals. RESULTS: A knowledge mean of 4.74 (95% CI 4.57-4.88) was observed for a scale of 10; specialist physicians scored higher (mean 5.21, 95% CI 4.81-5.60) than social workers (mean 3.07, 95% CI 2.31-3.82). Periodicity of the Pap test in most cases was less than 1 year and there was poor consensus about the age period during which the Pap test should be obtained. The knowledge level was lower when trying to identify etiologic aspects and treatment perspectives. CONCLUSIONS: The results of this study show that, besides the improvement of undergraduate academic programs, it is necessary to improve educational interventions for health care professionals through the updating, recycling, training, health education, and continuing medical education, among others, to promote professional competence and thus improve the quality of medical care.

Cervical cancer screening in developing countries: why is it ineffective? The case of Mexico.

BACKGROUND: Mexico established a national cervical cancer-screening program in 1974. Despite the implementation of the program, there was a steady mortality trend of 16 per 100,000 women over 15 years. METHODS: A diagnostic procedure of the pitfalls was applied to the following steps of the screening procedure: Pap sampling quality; cytological diagnosis validity; compliance of women; and determinants of non-participation. RESULTS: The low effectiveness of screening on cervical cancer is principally due to factors associated with quality and coverage. Pap quality is deficient; 64% of a random sample of specimens lacked endocervical cells. Reading centers presented false negative indices of between 10 and 54%. Women seek screening in a late stage of disease (55% with cervical cancer seek care because they have symptoms). In addition, coverage is low; in women between 15 and 49 years of age in Mexico City, 64.2% have a history of Pap, compared with 30% in rural areas. Knowledge of what the Pap is used for strongly determines the use of screening. In rural areas, only 40% of women are informed about the purpose of the Pap test. CONCLUSIONS: A proposal to reorganize Mexico's screening program includes the following five main strategies: (a) increased coverage; (b) improved quality control of how cervical smears are taken; (c) better interpretation of Pap tests; (d) guaranteed treatment for those whose tests show abnormalities, and (e) improved follow-up.

Barriers to early detection of cervical-uterine cancer in Mexico.

In Mexico, a woman dies of cervical-uterine cancer every 2 hours, indicating a low impact by the national program for early detection of this cancer, principally because of problems related to quality and coverage. Through a qualitative study, we identified the principal barriers to use of the detection program from the point of view of actual and potential program users. Four focus groups were organized in standard conditions in Mexico City (urban, developed) and in the southern state of Oaxaca (rural, economically disadvantaged area). Participants were either women with at least one previous Papanicolaou (Pap) test or women who had never had the test. Barriers to Pap test use included (1) lack of knowledge about cervical-uterine cancer etiology, (2) not knowing that the Pap test exists, (3) the conception that cancer is an inevitably fatal disease, (4) problems in doctor/medical institution-patient relationships, (5) giving priority to unmet needs related to extreme poverty, (6) opposition by the male sexual partner, (7) rejection of the pelvic examination, (8) long waits for sample collection and receiving results, and (9) perceived high costs for care. To increase coverage of the early detection program for cervical-uterine cancer in Mexico, the needs, perceptions, and beliefs of women and their partners must be taken into account when developing policy and planning, given the role these factors play in the decision-making process that leads to their participation or nonparticipation in this program.

[The factors that determine participation in cervical cancer screening in the state of Morelos]. / Factores que determinan la participación en el tamizaje de cáncer cervical en el estado de Morelos.

OBJECTIVE: To determine the main factors associated to participation in an early detection program of cancer (DPC), in a population with a high cervical cancer (CC) mortality rate. MATERIAL AND METHODS: A population-based, cross-sectional study was performed in the state of Morelos, which included 3,197 women aged between 15 and 49 years, randomly selected from a household sample frame of the 33 municipalities of the state. RESULTS: Awareness of the utility of the Papanicolaou (Pap) test (OR 29.6, 95% CI 23.6-37) and a former history of gynecological symptoms (OR 1.7, 95% CI 1.2-2.4) predisposed to greater use of the DPC. Factors associated to the use of the Pap test were precedents of using one contraceptive (OR 1.4, 95% CI 1.1-1.8) or two or more contraceptives (OR 2.1, 95% CI 1.6-2.8). CONCLUSIONS: In the state of Morelos, Mexico, screening for cervical cancer is offered opportunistically in the context of health care use. Therefore, the precedent of using health care services is the main determining factor for use of the DPC program. These results reveal the need to design alternative strategies to promote participation among women who have no access to health services, since they constitute the population group at highest risk of developing CC.

Evaluation model of the Mexican national program for early cervical cancer detection and proposals for a new approach.

INTRODUCTION: An evaluation model on cervical cancer (CC) prevention in Mexico was carried out during 1990-95, using three observation units: women at risk, screening providers, and use of health services. METHODS: A diagnostic procedure of the pitfalls was applied to the following steps of the screening procedure: Pap sampling quality, cytological diagnosis validity, compliance of women, and determinants of nonparticipation. RESULTS: The low effectiveness of screening for CC is due principally to factors associated with quality and coverage. Quality of Pap is deficient; 64 percent of a random sample of specimens lacked endocervical cells. Reading centers presented false negative indices between 10 and 54 percent. Women seek screening in a late stage of disease (55 percent with CC seek care because they have symptoms). In addition, coverage is low; in women between 15 and 49 years of age in Mexico City, 64.2 percent have a history of Pap smears, compared with 30 percent in rural areas. Knowledge of what the Pap is used for strongly determines use of screening. In rural areas, only 40 percent know the purpose of the Pap. CONCLUSIONS: This information justifies an intervention to reorganize CC screening in Mexico, through strategies for improving compliance, quality, follow-up, and treatment for abnormal screens.

The cervical cancer screening program in Mexico: problems with access and coverage.

A cross-sectional study was carried out in two geographic regions of Mexico - Oaxaca (rural area) and Mexico City (urban area) - to determine the main factors for predicting participation in Cervical Cytology Screening Programs (CCSP), in populations with high mortality due to cervical cancer. We included 4,208 women aged between 15 and 49 years, randomly selected through a national household-sample frame. Knowledge of what the Pap test is used for strongly predisposes use of CCSP in Mexico City (odds ratio [OR] = 46.1, 95 percent confidence interval [CI] = 33.1-64.1) and Oaxaca state (OR = 61.5, CI = 42.0-89.9), as well as high socioeconomic level (Mexico: OR = 2.0, CI = 1.1-7.6; Oaxaca: OR = 4.1, CI = 3.1-5.3), high education level (Mexico: OR = 3.6, CI = 1.5-8.8; Oaxaca: OR = 5.3, CI = 2.8-10.0), and access to social security (Mexico: OR = 1.7, CI = 1.4-2.2; Oaxaca: OR = 2.2, CI = 1.8-2.7). Low coverage of the CCSP is confirmed as an important problem in Mexico.

[Cost-benefit analysis of the Program for Early Screening of Cervico-uterine Cancer]. / Análisis costo beneficio del Programa de Detección Oportuna del Cáncer Cervicouterino.

OBJECTIVE: Previous researches pointed out the critical changes needed to increase the efficiency of the National Screening Programme of Cervical Cancer in Mexico. These changes were assessed through a cost-benefit analysis. This paper presents the results of that appraisal. Figures are presented as US Dollars of 1996 valued as 7.5 pesos for each dollar. RESULTS: The operational unitary cost of the integral process of the cytology-the obtention of the Pap smear, its transportation to the interpretation centre, its analysis, and the notification of results to users-was estimated in US$ 11.6. If the proposed changes are operated, the cost of each citology would increase by 32.7%. The benefit/cost ratio would be 2 and the net benefit of 88 millions of US dollars for the next five years. CONCLUSIONS: The operation of the proposed changes is socially desirable, but should be supported the training activities of the personnel, the increase of the coverage of women at risk, the quality control activities, the monitoring of the program and the communication with women detected as positive cases.

Human papilloma virus 16-18 infection and cervical cancer in Mexico: a case-control study.

Cervical cancer (CC) is one of the principal public health problems in Mexico. The national mortality rate due to CC was estimated at 21.8 per 100,000 among women over 15 years old during 1994. Despite this high incidence little is known in Mexico about the risk factors for CC. The objectives of the study were to evaluate the association between CC and HPV types 16 and 18 in women living in Mexico City. From August, 1990 to December, 1992, a case-control study was carried out in the metropolitan area of Mexico City. HPV 16-18 types were determined in a sample of 148 CC cases and 204 controls randomly selected from a sample frame representative of the metropolitan area of Mexico City. Sixty cases corresponded to in situ CC and 88 cases to the invasive phase. Determination of HPV 16 and 18 types was done by polymerase chain reaction using primers specific to E6/E7. Results showed that 48.3% of in situ CC cases and 48.8% of invasive CC cases were positive for HPV 16 while only 13.2% were positive among the 204 controls. Association between HPV 16 infection in the in situ cancer cases had an estimated odds ratio (OR) of 5.17 (95% CI 2.60-10.51). In the invasive cervical cancer cases, association between HPV 16 infection and invasive CC in this sample had an OR of 3.84 (95% CI 2.04-7.22). For the total sample, the estimated OR was 5.48 (95% CI 3.07-9.62). In the total sample, those women with a strong positive reaction to PCR were associated with a large increase in the risk, OR of 38.0 (95% CI 8.66-167.1). The prevalence the HPV 18 was 6.7%, only observed in the invasive cervical cancer cases. At present there is general consensus that HPV is the principal causal agent in C C etiology. This study intends to contribute to the knowledge concerning the etiology of cervical cancer. However, it is necessary to consider that the single most effective tool in the reduction of mortality due to cervical cancer has been the Pap test. Secondary prevention has proven to be highly effective in other populations, and this should be viewed as a priority activity for all at-risk populations. Although a vaccine for HPV may be available in the near future its efficacy in primary prevention has yet to be demonstrated.

Reproducibility study of cervical cytopathology in Mexico: a need for regulation and professional accreditation.

Due to the high rate of false negative results in diagnosis of cervical cytopathology, in many countries its practice has been transformed through the application of several interventions aimed at medical regulation to improve diagnostic accuracy. Diagnostic reproducibility of gynecological cytopathology was evaluated in a series of 20 cytology specimens [Papanicolaou (Pap)] and 20 cervical biopsy. (CB) studies in different clinical stages, during 1994. The observation unit consisted of 30 pathologists who observed 2 groups of 20 Pap and 20 CB specimens. The standard was a cytopathologist certified by the Pathological Anatomy Council of Mexico. Intraclass reproducibility in gynecological cytopathology is low in Mexico. In a group analysis, concordance increased as clinical status of the cervical lesion increased. For moderate dysplasia, concordance in Pap was kappa = 0.04, compared to 0.23 in CB. Concordance of diagnosis of invasive cancer was 0.29 for Pap and 0.64 for CB. Using weighted kappa at the individual level for all possible diagnoses, concordance varied from 0.29 to 0.59 for Pap, and 0.42 to 0.65 for CB. The problem of reproducibility in cervical cytopathology in Mexico emphasizes the need for continuing education, uniform diagnostic criteria, and the advantages of a single operational classification-possibly the Bethesda System-since current classification systems are obsolete.

Human papilloma virus 16-18 infection and cervical cancer in Mexico: A case-control study

Cervical cancer (CC) is one of the principal public health problems in Mexico. The national mortality rate due to CC was estimated at 21.8 per 100,000 among women over 15 years old during 1994. Despite this high incidence little is known in Mexico about the risk factors for CC. The objectives of the study were to evaluate the association between CC and HPV types 16 and 18 in women living in Mexico City. From august, 1990 to December, 1992, a case-control study was carried out in the metropolitan area of Mexico City. HPV 16-18 types were determined in a sample of 148 CC caes and 204 controls randomly selected from a sample frame representative of the metropolitan area of Mexico City. Sixty cases corresponded to in situ CC and 88 cases to the invasive phase. Determination of HPV 16 and 18 types was done by polymerase chain reaction using primers specific to E6/E7. Results showed that 48.3 percent of in situ CC cases and 48.8 percent of invasive CC cases were positive for HPV16 while only 13.2 percent were positive among the 204 controls. Association Between HPV 16 infection in the in situ cancer cases had an estimated odds ratio (OR) of 5.17 (95 percent CI 2.60 - 10.51). In the invasive cervical cancer cases, association between HPV 16 infection and invasive CC in this sample had an OR of 3.84 (95 percent CI 2.04 - 7.22). For the total sample, the estimated OR was 5.48 (95 percent CI 3.07-9.62). In the total sample, those women with a strong positive reaction to PCR were associated with a large increase in the risk, OR of 38.0(95 percent CI 8.66-167.1) The prevalence the HPV 18 was 6.7 percent, only observed in the invasive cervical cancer cases. At present there is general consensus that HPV is the principal causal agent in CC etiology. This study intends to contribute to the knowledge concerning the etiology of cervical cancer. However, it is necessary to consider that the single most effective tool in the reduction of mortality due to cervical cancer has been the Pap test. Secondary prevention has proven to be highly effective in other populations, and this should be viewed as a priority activity for all at-risk populations. Athough a vaccine for HPV may be avalilable in the near future its efficacy in primary prevention has yet to be demonstrated

Validity and reproducibility of cytologic diagnosis in a sample of cervical cancer screening centers in Mexico.

OBJECTIVE: To evaluate the diagnostic precision of the cervical cytology (smear) in a sample of 16 cervical cancer screening centers (CCSCs) from the Mexican Ministry of Health and Mexican Institute for Social Security CCSCs distributed across the country. STUDY DESIGN: Each center received a batch of 90 cytologic specimens with a random positive prevalence of 1.5-36%. Positive cases were always histologically confirmed. The "gold standard" was an expert pathologist certified by the Mexican Board of Pathology. RESULTS: Our results show that cytologic diagnosis validity and reproducibility vary greatly within and between institutions. The false negative rate (FNR) varied between 10% and 54%, independent of the prevalence of positive cases. CONCLUSION: Quality control of diagnostic precision is central to the consistency of results obtained at CCSCs. In Mexico the high FNR calls for governmental regulation of cytopathology policies and methods, such as through national and international accreditation of cytotechnology programs. In order to decrease the FNR, developing countries must frame managerial development strategies to streamline the cervical cancer screening program, including continuing education, improvement of operation processes in CCSCs, internal and external quality control of cytopathology laboratories and cervical sampling procedures, and standardization of diagnostic criteria.

[Breast cancer. A historical account, present and future]. / Cáncer de mama. Un hilo conductor histórico, presente y futuro.

This essay describes the different theoretical constructions of breast cancer models, such as the biological, hygienist-preventive and epidemiological. An anecdotal account of the Hippocratic model is also presented. This disease will be one of the major challenges posed by noncommunicable diseases in coming years, due to a significant increase of life expectancy and to a decrease of the overall annual growth rate-resulting in the ageing of the population-, as well as to lifestyle changes-particularly the considerable decrease of fertility rates and breastfeeding practices-, and to the poor efficiency and effectiveness of breast cancer screening programs. In this context, one of the main challenges for breast cancer control is to secure the multidisciplinary approach offered by public health. After analyzing the different models, we favor the sociomedical model as the one that incorporates several areas of knowledge to formulate an effective response to breast cancer.

[Reproductive risk factors and sexual history associated with cervical cancer in Mexico]. / Factores de riesgo reproductivo e historia de vida sexual asociados a cáncer cervical en México.

Uterine cervical cancer is one of the principal public health problems in Mexico. The national mortality rate for cervical cancer in 1991 is estimated at 9.5 per 100,000 women, representing 4,194 deaths. In the period from August 1990 to December 1992, a case-control study was carried out that included 630 cases of histologically confirmed cervical cancer in eight Mexico City hospitals (two for people with no social security cover, four of the social security system and two private). As controls, 1,005 women were chosen from a random sampling of houses in the Mexico City metropolitan area. The main cervical cancer risk factors found in this study, adjusted for a multivariate model, were multiple normals births (with five births OR of 1.93 and 95% C.I. of 1.22-2.73) and a history of two or more sex partners (the OR with four or more sex partners was 5.56 and a C.I. of 2.3-13.4). In addition, there was an estimated lower risk of disease related to starting a sex life after 25 years of age (OR 0.41 with C.I. of 0.25-0.69) and to having cesareans as compared versus one normal birth (OR 0.28 and C.I. of 0.13-0.61). The information obtained is relevant since it identifies Mexican women with a high-risk of developing cervical cancer which can be used in planning programs for the early detection of cancer in this population.

Gallstone composition in Mexican patients.

Prevalence of gallstone disease in Mexico is similar to that found in some European countries. Patients from those industrialized Western countries primarily develop cholesterol gallstones; however, we do not have information related to the chemical composition of gallstones in the Mexican population. The aim of this study was to determine the physiochemical characteristics of gallstones from patients undergoing surgery for symptomatic cholelithiasis. We analyzed gallstone specimens from 59 patients (17 male and 42 female) from five Mexican states and Mexico City by X-ray diffraction. The chemical analysis revealed that 71.2% of the patients had stones of mixed composition. We concluded that the chemical composition of gallstones found in Mexican patients is similar to that found in patients from other Western countries.

[Evaluation of a program for the early detection of cancer of the uterine cervix in Mexico City. A populational-based epidemiologic study of cases and controls]. / Evaluación del programa de detección oportuna del cáncer del cuello uterino en la Ciudad de México. Un estudio epidemiológico de casos y controles con base poblacional.

Cervical cancer is still an important public health problem in Mexico; in spite of the development of various programs aimed at lowering mortality due to this disease, impact has not yet been achieved. In this study we present an evaluation of the Early Detection Program for Cervical Cancer in Mexico City. The authors carried out a case-control study with a populational base, in which a sample of cases obtained in eight hospitals and a sample of controls representative of the general population were included. We report a protective effect attributed to the program. The women with complete cytology showed 2.4 times less risk of cervical cancer. Nevertheless the effect of the program at a populational level is still limited because it covers only 20 per cent of the cases in the population. The results indicate the need for developing operative research programs in order to increase the demand for and the quality and efficiency of preventive services.

[Cancer of the uterine cervix. Historical perspective]. / Cáncer de cuello uterino. Una perspectiva histórica.

This paper describes the existing etiological paradigms which explain the development of cervical cancer (CACU), and particular, is a review of the historical attempts to explain the occurrence of the disease. Previous analysis concerning the prevalence of CACU in populations has been based on empirical work which can be summarized in several public health models, including: biomedical, hygienist-preventive, epidemiologic, ecologic, and social medical. We conclude that the existing paradigms must be reoriented in order to formulate organized social responses for the control of CACU.

Prevalence of gallstone disease in Mexico. A necropsy study.

The prevalence of gallstone disease in Mexico was investigated by studying a sample of 21,446 necropsies performed at the Department of Pathology of the General Hospital of Mexico City during a 35-year period (1953-1988). For each decade, 1000 necropsy cases were randomly selected. The crude prevalence of gallstone disease was 14.3%, 8.5% for males and 20.4% for females. The age groups ranged from 20 to more than 80 years old; the age-standardized prevalence for males was 5.6% and for females 16.2%. These rates are intermediate between those found in Chile and some African countries, comparable to some European studies, and less than those found in Mexican-Americans. No significant trend in the prevalence of gallstone disease was found when the different decades were compared.