Gastrointestinal stromal tumors: clinical and pathological analysis of 24 cases.

BACKGROUND: Gastrointestinal stromal tumors (GISTs) are mesenchymal neoplasms of the gastrointestinal tract. They are positive for the expression of c-Kit protein at immunohistochemistry and their clinical presentation is variable. We conducted a study to identify true GISTs with known pathological and immunohistochemical criteria from other tumors of the gastrointestinal tract. METHODS: The clinical records of patients with the diagnosis of schwannoma, leiomyoma, leiomyosarcoma and tumor of uncertain biological behavior of the gastrointestinal tract were identified and the slides of paraffin obtained for review by two experienced pathologists in the diagnosis of GISTs. The clinical presentation, treatment and outcomes were analyzed. RESULTS: Twenty four GISTs (11 low-risk and 13 high-risk) were identified from 76 cases reviewed. All the confirmed GISTs were positive at immunohistochemistry for c-Kit expression. The two predominant location of the tumors were the stomach and small intestine. The outcome was good for benign and completely resected tumors. CONCLUSIONS: True GISTs can be recognized from other tumors by histological analysis. Immunohistochemistry to identify c-Kit protein expression is useful to confirm the diagnosis. Physicians must consider GISTs in patients with a lesion of the gastrointestinal tract resembling a smooth muscle tumor or/and in association with chronic or acute bleeding.

Fibrolamellar hepatocellular carcinoma in mexican patients.

UNLABELLED: The aim of this report is to describe the frequency, clinical, and morphologic characteristics of fibrolamellar hepatocellular carcinoma in Mexican patients. Fibrolamellar hepatocellular carcinoma (FLHCC) is a rare variant of hepatocellular carcinoma. Although this tumor appears to be predominant among the Caucasian population of the U.S, FLHCC has been described in many other countries. The frequency and characteristics of FLHCC in Latin American population is almost unknown. The clinico-pathologic characteristics of seven (5.8%) Mexican patients with FLHCC, obtained among 121 hepato-cellular carcinomas are described. The frequency of these tumors was compared with the frequency reported in other geographic areas in the international literature between 1980 and 1999. There were four women and three men. Two patients had taken oral contraceptives for six months and a year prior to diagnosis; another patient had positive serology for the hepatitis B virus. Common symptoms included a palpable mass, abdominal pain and weight loss; two patients presented jaundice. In two patients the tumor had been removed eight and three years previously, and they were readmitted when FLHCC recurred. In three patients the diagnosis was suspected in radiological studies (computed tomography and/or magnetic resonance). Laboratory tests were non-specific. In four patients, resection of the tumor was performed, and in the remaining three the neoplasm was diagnosed by percutaneous hepatic biopsy. Two patients had died of disease at the time of the study, and another was alive with recurrent disease. CONCLUSIONS: fibrolamellar hepatocarcinoma is an uncommon, but not an exceptional neoplasm in our population and represents 5.8% of all hepatocarcinomas reviewed.

Atypical histiocytic infiltration simulating diffuse-type carcinoma in a gastric ulcer due to non-steroidal anti-inflammatory drugs.

A 83-year old man treated with naproxen during two years was admitted because of hypovolemia and peritoneal irritation. A panendoscopic study was performed and an ulcer localized at the large curvature of the stomach was disclosed. In the gastrectomy specimen the ulcer showed necrosis, edema, fibrosis, chronic inflammatory infiltrate with lymphocytes and plasma cells. Additionally, atypical cells with irregular and hyperchromatic nuclei or vacuolated cytoplasm were seen in the lamina propia and infiltrating the muscular layers; isolated signet-ring-like cells were also seen. Histochemical study with periodic acid-Schiff, mucicarmin, and colloidal stains revealed mucosubstances in these cells. A poorly differentiated carcinoma was initially diagnosed. However, the immunohistochemical study were positive for histiocytic markers (CD-68, S-100 protein) and negative for epithelial markers (cytokeratin; and epithelial membrane antigen). The positivity of mucus stains in the histiocytes could be explained in this case by phagocytosis of mucous substances released from broken hyperplastic glands in the vicinity of the ulcer. To our knowledge, atypical histiocytic infiltration in gastric ulcers has not been previously described; thus, it should be included in the group of gastric carcinoma mimicks.

Alteraciones vasculares con el suministro de ácido glucurónico a ratas / Vascular lesions because of glucuronic acid in rats

Después de haber observado que los pacientes diabéticos tienen elevadas las concentraciones plasmáticas de bilirrubina conjugada y de ácido glucurónico y conociendo que éste forma parte de la estructura química de los glucosaminoglicanos (ácido hialurónico, heparina y condroitín), que a su vez forman parte de la estructura de los capilares, vasos de mayor calibre y tejido conectivo, planteamos la hipótesis de que las elevaciones de las concentraciones de ácido glucurónico originan la elevación de los niveles de glucosaminoglicanos, y de que éstos intervienen en forma fundamental en las lesiones vasculares que presentan como complicación crónica los pacientes con diabetes mellitus. Se trató a 10 ratas Wistar con ácido glucurónico (30 mg) en 50 ml de agua para beberlo ad livitum por tiempo sin definir. A los 60 días, todas las ratas estaban ciegas y no respondían a estímulos luminosos. Estudios de oftalmoscopia, anatomopatológicos del ojo y riñón y de microscopia electrónica del riñón confirmaron la presencia de lesiones vasculares con formación de edema, congestión de vasos, microaneurismas y hemorragias, y en todos los estudios se encontró engrosamiento de membrana basal. Se concluye que el ácido glucurónico suministrado oralmente a ratas es capaz de reproducir las lesiones vasculares que como complicación crónica presenta las personas con diabetes mellitus