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Gastric cancer is one of the most frequent neoplasias in the digestive tract and is the result of premalignant lesion progression in the majority of cases. Opportune detection of those lesions is relevant, given that timely treatment offers the possibility of cure. There is no consensus in Mexico on the early detection of gastric cancer, and therefore, the Asociación Mexicana de Gastroenterología brought together a group of experts and produced the "Mexican consensus on the detection and treatment of early gastric cancer" to establish useful recommendations for the medical community. The Delphi methodology was employed, and 38 recommendations related to early gastric cancer were formulated. The consensus defines early gastric cancer as that which at diagnosis is limited to the mucosa and submucosa, irrespective of lymph node metástasis. In Mexico, as in other parts of the world, factors associated with early gastric cancer include Helicobacter pylori infection, a family history of the disease, smoking, and diet. Chromoendoscopy, magnification endoscopy, and equipment-based image-enhanced endoscopy are recommended for making the diagnosis, and accurate histopathologic diagnosis is invaluable for making therapeutic decisions. The endoscopic treatment of early gastric cancer, whether dissection or resection of the mucosa, should be preferred to surgical management, when similar oncologic cure results can be obtained. Endoscopic surveillance should be individualized.

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BACKGROUND: Liver transplantation (LT) in Wilson s disease (WD) is mostly indicated when progressing liver disease or acute liver failure occurs. In patients with neurological manifestations, this procedure has not gained wide acceptance based on previous reports of dismal prognosis. OBJECTIVE: To describe a Mexican cohort of pa- tients with WD with special focus on LT in patients with deteriorating neurological manifestations. MATERIAL AND METHODS: Patients with confirmed WD and their first-degree relatives were evaluated at the hepatology clinic of a tertiary referral hospital. Attention was placed on therapy and outcome. RESULTS: Eleven patients were followed for a period of up to 80 months (7 probands and 4 affected family members), 10 patients having hepatic manifestations and 4 having neuro psychia- tric phenomena. Pharmacologic treatment was uniform in most patients, and LT was indicated in 2 cases because of deteriorating neurological status. These patients had total remission of their neurological manifestations with marked improvement on imaging studies. CONCLUSIONS: Follow-up and pharmacologic treatment was flawed by several adverse conditions present in our population. Patients with progressing neurological disease had a favorable outcome after LT, a similar response to the one reported by several authors. In conclusion, LT should be strongly considered for the treatment of these patients.

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BACKGROUND: The intestinal gastric cancer is preceded by a sequence of pathological changes whose link is mucosal atrophy. The modified Sydney system for atrophy is a parameter not reproducible among pathologists. AIM: To know the interobserver variability using the OLGA system (Operative Link on Gastritis Assessment). METHODS: We selected 116 histologic slides. Sixty cases of both types of atrophy and 56 without atrophy were included. Three general pathologists, interested in gastrointestinal biopsies independently review the slides and established a diagnosis. For statistical analyses we employed singles frequencies in order to describe the individual diagnosis and the kappa test for evaluate the concordance between 2 and 4 observers with 2 and 3 categories. RESULTS: The global concordance has a kappa index of 0.48 (IC 95% 0.4-0.57). When we compared two pathologists the kappa index varies from 0.82(IC 95% 0.73-0.91) to 0.36 (IC 95% 0.22-0.5). The consensus among three pathologists was achieved in 25 out 30 slides in the metaplastic variety and 11 out 30 for the non-metaplastic type. The concordance for the atrophy scale has a kappa index between 0.2 and 0.5. CONCLUSION: The problematic atrophic evaluation with the Sydney system justify every effort to improve the interobserver evaluation. The OLGA system seems reproducible, although laborious,it requires a careful application, but with daily practice it could be applied easier. The clinician acceptation becomes crucial.

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INTRODUCTION: Fine-needle aspiration biopsy (FNAB) is currently considered the most reliable and cost effective examination for diagnosis of solitary thyroid nodules prior to surgery. Because of its great utility the indication of intraoperative examination (IOE) (macroscopic examination, cytology and frozen section), has recently been questioned. OBJECTIVE: To compare the accuracy of the FNAB and IOE, in those patients with nodular thyroid disease who undergo thyroidectomy. As well as to analyse the, discrepant cases by FNAB. MATERIAL AND METHODS: The results of IOE and FNAB were compared in a period of two years (1997-98) at the Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán (INCMNSZ). In all cases the diagnosis established from paraffin embedded tissue sections was considered to be the gold standard. The cytologyc smears and the histologic sections of the discrepant cases were reviewed. RESULTS: One thousand and fourteen IOE were done during two consecutive years; from these cases, 136 (13.4%) were thyroid lesions. Half of the thyroid lesions (69 cases) corresponded to carcinomas, the others were follicular adenomas (13 cases) and non-neoplasic lesions (54 cases). The analysis of the copacity to discriminate between malignant and benign diseases with IOE and FNAB demonstrated sensitivity of 89% (CI: 78.2-95.1) and 97.7% (CI: 86.8-99.9), specificity of 100% (CI: 93.1-100) and 90% (CI: 90.4-96.7). The positive predictive value of 100% and 91.6%, negative predictive value of 90.4% and 97.3%, and equal accuracy (94.6% and 94.1% respectively). When the analysis of capacity to stratify diseases was performed, IOE and FNAB showed similar percentages in all the cases, including the follicular adenomas and carcinomas. The causes of false positive and false negative cases by FNAB, reproduce what has been written in the literature. CONCLUSIONS: FNAB preoperative examination is adequate for the selection of patients that undergo thyroidectomy. Nevertheless, IOE should be done in most of the cases, and routinely in those cases with inconclusive FNAB results and in cases of follicular tumor.

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Depending on geographic location and patient age Hodgkin's disease (HD) is associated with Epstein-Barr virus (EBV), mostly type A EBV, in 20% to 100%. The highest prevalence occurs in children of developing countries. Molecular analysis of the oncogene coding for the latent membrane protein 1 (LMP-1) revealed a 30-base pair (bp) deletion in up to 46% of EBV-positive HD. We investigated the presence of EBV in a series of Mexican classical HD (n = 57) and reactive lymphoid tissues (n = 20) from a private and a public hospital with special emphasis on the prevalence of the 30-bp deletion and the type of EBV. EBV infection was analyzed at the cellular level by Epstein-Barr encoded early RNA transcripts (EBER) in situ hybridization (ISH) and by LMP-1 protein immunohistochemistry (IHC). Molecular analysis of the LMP-1 gene configuration was performed by polymerase chain reaction (PCR) with primers spanning the site of the deletion and subsequent Southern and/or dot blot hybridization using wild-type and deletion-specific probes. The prevalence of type A and type B EBV was investigated by PCR-analysis for divergence in the coding region of Epstein-Barr nuclear antigen (EBNA)-2. EBV was detected in Hodgkin- and Reed-Sternberg cells (H-RS) by LMP-1 IHC and/or EBER ISH in 35/57 (61%) Mexican HD including 18/32 (56%) with nodular sclerosis, 15/20 (75%) with mixed cellularity and 2/4 (50%) with lymphocyte depletion. In addition, LMP-1 gene sequences were detected by PCR in 9 cases of HD without LMP/EBER expression by H-RS cells and in 17/20 (85%) reactive lymph nodes, supposedly originating from rare latently infected B cells. Surprisingly, the 30-bp LMP-1 deletion was found in 28/35 (80%) EBV-positive HD. This deletion, however, was also found in all 9 (100%) HD with H-RS cells negative for EBV and in 10/17 (59%) reactive lymph nodes. Thus, the overall LMP-1 del prevalence in reactive tissue is 73% (19/26). Typing of EBV was successful in 26 cases of EBV-positive HD, 10 of these were infected by type B EBV (38%). Of the reactive lymphoid tissue, 9 (47%) were infected by type A, and 10 (53%) by type B; All 20 cases (100%) associated with type B, whether neoplastic or reactive, displayed the LMP-1 del variant compared with 18/25 (72%) infected by type A EBV. To our knowledge, this is the highest incidence for both the LMP-1 deletion variant and the infection by type B EBV in HD reported so far worldwide. Our data suggest that EBV infection contributes to the pathogenesis of the majority of Hodgkin's disease cases in Mexico. The specific tumorigenic role of the LMP-1 deletion variant, however, is doubtful with regard to its high frequency in nonneoplastic lesions. Moreover, type B infection frequently occurs in Mexican HD and reactive lymphoid tissue and is consistently associated with the deletion variant pointing to a pathogenetic role of this combined genotype.

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OBJECTIVE: To evaluate the information content in our surgical pathology reports of colon and rectum carcinoma. SETTING: A third level hospital. DESIGN: Consecutive surgical reports from 1988 to 1994 were retrieved. The gross and histological variables with prognostic relevance according to the TNM system were registered using a checklist with standardized variables as proposed by two groups of pathologists. The adequacy of our reports was surveyed counting the number of histopathological variables in relation to the 11 prognostic parameters that must be included in routine surgical reports of large colon carcinomas. RESULTS: The surgical reports were 135. The histologic type, tumor grade and histological tumor invasion were provided in most of the reports. In 90% the lymph node characteristics were described and 85% had gross and histologic margin assessment. But other variables were poorly informed, i.e. vascular invasion was informed in one case (0.7%). CONCLUSIONS: Our surgical reports were considered adequate as 113/135 (84%) recorded more than eight prognostic variables. Insufficient data were: 1) a poor gross description; 2) lack of tumor grading in 12%; and 3) omission of anatomic site in 29%.

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A case of a 38-year-old male having an acinic cell adenocarcinoma of the parotid gland is reported. The tumor measured 22 cm and histologically it was of the papillary-cystic type. The following features were of interest: 1) the tumor size surpassed the size of previous reported acinic cell adenocarcinomas by 9 cm; and 2) the rarity of its histological variety (cystic papillary) demanded immunohistochemical and electron microscopic studies to confirm the diagnosis.

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Recently the association between the Epstein-Barr virus (EBV) and smooth muscle lesions has been described in immunosuppressed children but it is infrequent in adults. The role of EBV in the pathogenesis of these lesions is obscure. We presents a 28 year old man with end stage renal disease transplanted in 1994. Two years later he developed several nodular lesions that affected both lungs, liver, spleen, retroperitoneal ganglia and the left thigh; one year later he died. The surgical specimen from the thigh and a liver biopsy were diagnosed as leiomyosarcoma. Immunohistochemical reactions against vimentin and smooth muscle actin were positive. In situ hybridization disclosed positivity against EBV nuclear antigens (EBNA-2) in neoplasic cells. This is the first case of sarcoma in transplanted patients of our institution and represents a rare case of leiomyosarcoma associated with EBV in adults.

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We describe the clinicopathological characteristics and postmortem findings of three cases of intramucosal early gastric cancer (EGC) selected from nine cases of our series to characterize its unusual clinical behavior. All patients were treated at the Instituto Nacional de la Nutricion in Mexico City between January 1986 and December 1995. The following features were the most salient of the three cases: (1) The tumors were constituted by only few nests of intramucosal cells; two of them were signet-ring cell carcinomas and the other one was of the intestinal type. (2) Grossly, all tumors were inconspicuous. (3) All the patients had a short clinical course and in none of them the clinical diagnosis was suspected. (4) A wide dissemination was found at autopsy; additionally, in two of the cases, extensive lymphatic and venous thrombi and multiple secondary hemorrhages were found. (5) In all patients, the symptoms and deaths were caused by the metastases. No cases as early as those reported here were found either in the Japanese or in Western literature. Although larger series of EGC should be studied in our country, these findings suggest that at least in Mexico there is a group of EGC with unusual aggressive behavior.

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