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.

Hepatic carcinoma with spleen metastasis in a California sea lion from the Gulf of California.

A primary hepatic carcinoma with a neuroendocrine pattern was detected in an adult female California sea lion (Zalophus californianus) found dead on Granito Island in the Gulf of California (Mexico) in January 1996. At necropsy, several light yellow nodules of different sizes were observed on the entire surface of the liver and spleen. Microscopic examination of these nodules using routine haematoxylin-eosin stain, revealed cubic, polyhedral and pleomorphic cells with three to four bizarre mitotic figures per field (40X). An immunohistochemistry test revealed a positive reaction of indirect immunoperoxide to cytokeratin (CK2). This is the first known case of a primary hepatic carcinoma in free-ranging California sea lions from Mexican waters.

[Atypical biological behavior of alveolar rhabdomyosarcoma in five patients]. / Comportamiento biológico atípico del rabdomiosarcoma alveolar en cinco pacientes.

Five cases of alveolar rhabdomyosarcoma with atypical clinical features are reported. Three patients showed lymphadenopathy as the first clinical manifestation, mimicking a lymphoma or a non identified primary tumor with lymph node metastases. One patient presented systemic neoplastic disease and two had the primary tumor in atypical locations, such as the mediastinum and retroperitoneum. All patients died and in four of them an autopsy was performed. The histological diagnosis was confirmed by immunohistochemical studies on four cases. The alveolar rhabdomyosarcoma has a poor prognosis and can have a variable clinical presentation and morphology, simulating lymphomas, leukemias and systemic metastatic disease with an unknown primary neoplasm, such as in the cases here in reported.

[Third case of human hepatic capillariasis in Mexico]. / Tercer caso de capilariasis hepática humana en México.

A case of hepatic capillariasis in a 54-year-old woman confined to a mental institution is reported. The patient was transferred to the Hospital General de México for terminal care of a breast cancer; she died 12 days after admission. Hepatomegaly was observed clinically and numerous Capillaria hepatica eggs were found at autopsy. The laboratory examinations did not show eosinophilia or other abnormalities. Twenty-six cases of human hepatic capillariasis have been recorded in the world literature. This is the third case reported in Mexico: the previous two in children. Since the patient had a psychiatric condition she may have had aberrant alimentary habits. The features of C hepatica eggs stained with Jone's silver methenamine, which allows the demonstration of an internal multilayered sheath and an external layer endowed with multiple radiated canaliculi, are described in this patient.

Biochemical epidemiology of gallbladder cancer.

To evaluate the a priori hypotheses that an increased level of glyco and tauro lithocholic acid, perhaps because of a decreased capacity for hepatic sulfation, contributed to the biochemical epidemiology of gallbladder cancer, a case-control study was undertaken at four hospitals in La Paz, Bolivia, and at one hospital in Mexico City, Mexico. Eighty-four cases with newly diagnosed histologically confirmed gallbladder cancer were compared with 264 controls with cholelithiasis or choledocholithiasis in the absence of cancer and with 126 controls with normal biliary tracts. All study subjects were undergoing abdominal surgery. Interview data were collected for all study subjects, as well as blood, bile, and gallstone specimens when feasible. Sera were analyzed for carcinoembryonic antigen, cholesterol concentration, and total bile acids. Bile specimens were analyzed for carcinoembryonic antigen; and for concentration of bile salts; cholesterol; phospholipids; and the glycine and taurine conjugates of cholic, ursodeoxycholic, chenodeoxycholic, deoxycholic, and lithocholates; sulfoglycolithocholate; and sulfotaurolithocholate. Gallstone specimens were analyzed for the percentage of cholesterol content, the percentage of calcium bilirubinate content, and the percentage of calcium carbonate content. Serum bile acids were increased in cases versus the two control groups (median 11.7 nmol/mL vs. 9.3 nmol/mL for stone controls and 8.2 nmol/L for nonstone controls, P < or = .02 for each pairwise comparison). Biliary bile acids were markedly decreased in the cases (median 3.98 micromol/mL vs. 33.09 micromol/mL, and 154.0 micromol/L, respectively, P < or = .0001 for each comparison), even after excluding those with a serum bilirubin higher than 2.0 mg/dL. Bile cholesterol was lower for the cases as well (median 1.70 micromol/mL vs. 4.90 micromol/mL, and 16.81 micromol/ mL, respectively, P < or = .02), as was the concentration of bile phospholipids (median 2.97 micromol/mL vs. 6.26 micromol/mL, and 52.69 micromol/mL, P = .1 and .0004, respectively). Contrary to our a priori hypothesis, there was no difference between the cases and either control group in their bile concentrations of lithocholate, the proportion of bile acids which were sulfated, or the concentration of nonsulfated lithocholate. However, the cases had a higher concentration of ursodeoxycholate (UDC) (P < .004 for both control groups), especially glycoursodeoxycholate (P < .001 for both control groups). A previously published suggestion that gallstone size differed between cases and controls was not confirmed. In conclusion, cases with gallbladder cancer differed from controls with stones and from controls with normal biliary tracts in their serum and bile biochemistries. These findings may be a reflection of the disease process, or may provide useful clues to its pathogenesis.

p53 mutations in gastric and colorectal cancers in Texas Hispanics versus Anglos.

Gastric cancer is more than twice as common in Hispanics as in Anglos in Texas, while colorectal cancer is almost twice as common in Anglos as Hispanics. To test the hypothesis that mutations in the p53 tumour suppressor gene are involved in these differences, we examined 131 gastric and 138 colorectal cancers from Hispanic and Anglo patients from South Texas and Mexico using immunohistochemistry (IHC) as a screening assay for p53 mutations. The fraction of p53 positive cases was not significantly different in gastric cancers from Hispanics compared to Anglos (43% versus 61%, respectively, p = 0.13) or in colorectal cancer (57% versus 58%, respectively, p = 1.0), suggesting that p53 mutations are not involved in causing the different incidences of these cancers in these populations. In addition, the types of p53 mutations arising in gastric tumours from Hispanic patients were consistent with those reported in gastric tumours in other populations. Sequencing of mutations in five gastric cancers revealed two G:C to A:T transitions, two A:T to G:C transitions and one complex deletion. In contrast with findings in studies in other tumour types, neither stage nor survival was associated with p53 positive staining by IHC in either gastric or colorectal tumours in this study. Positive p53 immunostaining was associated with the diffuse histological subtype in gastric carcinoma (p = 0.05) and high histological grade in colorectal carcinoma (p = 0.04).

Serum CEA and CA 19-9: potential future diagnostic or screening tests for gallbladder cancer?

The poor prognosis of gallbladder cancer and the presence of high-risk populations make the identification of a screening test for this disease very desirable. As part of an ongoing case-control study of gallbladder cancer being conducted in Mexico City, Mexico, and in La Paz, Bolivia, blood specimens were sought from all patients with cancer of the gallbladder and on controls of similar age and sex undergoing upper abdominal surgery. Each sample was analyzed for carcino-embryonic antigen (CEA) and CA 19-9. Using the specimens from Bolivia, a serum CEA cutoff of 4.0 ng/ml yielded a sensitivity of 50.0% and a specificity of 92.7%, while a serum CA 19-9 cutoff of 20.0 units/ml yielded a sensitivity of 79.4% and a specificity of 79.2%. Using ROC curve analysis, the latter was a much better test than the former (p less than 0.05). Using the tests in series or in parallel did not substantively improve the results. The specimens from Mexico were used for validation purposes, and yielded very similar results. In conclusion, serum CA 19-9 and CEA are fairly good tests for discriminating patients with gallbladder cancer from patients with gallstones and no cancer, the former being a better test than the latter. These tests may be useful in identifying disease recurrences. In addition, if a sufficiently high-risk population could be identified, this could potentially become a useful screening test for this serious disease, allowing early intervention. However, additional data are needed prior to recommending this clinically.

Unsuspected pregnancy in a patient with a large prolactin-producing pituitary adenoma.

Se presenta el caso de una paciente de 38 anos de edad, con historia de amenorreagalactorrea de 20 anos de evolucion, quien desarrollo hipertension endocraneana y perdida de vision coincidente con embarazo espontaneo que paso inadvertido hasta la semana 26 de gestacion. El estudio endocrinologico de la paciente mostro niveles basales plasmaticos de prolactina y LH muy elevados, en tanto que los de FSH fueron comparables a los observados en la parte media del ciclo ovulatorio; hubo una respuesta subnormal en los niveles plasmaticos de HGH durante la administracion endovenosa de 1-arginina e insulina y falta de la inhibicion normal durante hipoglicemia; los niveles plasmaticos de TSH estudiaron moderadamente elevados. El estudio neurorradiologico mostro una erosion de la silla turca tipo V y una gran masa intra y supraselar que obstruia parcialmente al agujero de Monro. El caso fue tratado en 2 tiempos quirurgicos, primero transfenoidal y despues subfrontal, que condicionaron una mejoria de la vision.El estudio histopatologico con tecnica de inmunoperoxidasa mostro una adenoma hipofisario intensamente positivo para prolactina. El embarazo termino a las 27 semanas de gestacion con un producto vivo (peso de 1,100 g), sin estigmas fisicos que murio 5 horas despues.Este caso representa una situacion excepcional de embarazo espontaneo en una mujer con 20 anos de amenorrea-galactorrea debida a un gran hipofisario secretor de prolactina