Pathology of gastric cancer

This paper reviews the gross morphology, histologic classification, location, and modes of spread of gastric cancer. On the basis of gross appearance, we have classified gastric carcinoma into 4 types: (a) superficial spreading (6% of cases), (b) polypoid (11% of cases), (c) ulcerated (45% of cases), and (d) diffuse infiltrating (38% of cases). Our histologic classification includes 4 categories: (a) adenocarcinoma (70% of cases), (b) round cell carcinoma, (c) mucinous carcinoma, and (d) rare forms of carcinoma (squamous, adenoacanthoma, carcinosarcoma, collision tumor, ductogenic carcinoma). These main histologie categories are subdivided according to the degree of differentiation of each tumor. From 81 to 86% of gastric cancers arise in the pyloric region. Multifocal origin of stomach cancers occurs in about 10% of cases. The prognosis of gastric cancer depends on the extent of spread at the time of treatment. Intramural propagation beyond the grossly apparent margins is common, and extension into the duodenum and esophagus from lesions in the pylorus and cardia regularly occurs. Approximately 50% of gastric cancers infiltrate neighboring organs. Metastases to regional lymph nodes, particularly in the lesser curvature drainage area, occur in over half of the cases. Blood-borne spread, to the liver and beyond, and peritoneal seeding are common.

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Résumé L'article revoit la morphologie macroscopique, la classification histologique, la localisation et les modes d'extension du cancer gastrique. Nous avons classé les carcinomes gastriques, sur base de leur aspect macroscopique, en 4 types: (a) avec extension superficielle (6% des cas), (b) polypoïdes (11% des cas), (c) ulcérés (45% des cas), (d) diffusément infiltrants (38% des cas). Notre classification histologique comporte 4 catégories: (a) adénocarcinome (70% des cas), (b) carcinome à cellules rondes, (c) carcinome muqueux, (d) formes rares de carcinomes (épithélioma spino-cellulaire, adénoacanthome, carcinosarcome, tumeurs en collision, carcinome tubulaire). Ces grandes catégories histologiques sont subdivisées selon le degré de différenciation de chaque tumeur. Le cancer gastrique a son origine dans la région prépylorique dans 81–86% des cas. Dans quelques 10% des cas, le cancer a une origine multifocale. Le pronostic dépend de l'étendue de la dissémination au moment du traitement. La tumeur s'étend souvent dans la paroi gastrique au-delà de ses marges apparentes. L'extension au duodénum pour les lésions pyloriques, et à l'oesophage pour les lésions du cardia, est fréquente. Quelques 50% des cancers gastriques infiltrent les organes voisins. On trouve, dans plus de la moitié des cas, des métastases ganglionnaires régionales, surtout dans les zones de drainage de la petite courbure. Les métastases par voie sanguine, dans le foie ou au-delà, et la dissémination péritonéale sont fréquentes.

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Dedicated to Prof. Dr. med., Dr. med. h. c. W. Doerr, 65th Anniversary.     

Work in progress: the application of temporal filtering techniques to hybrid subtraction in digital subtraction angiography

Temporal filtering methods were applied to iodine signal-to-noise ratio (SNR) restoration in intravenous hybrid subtraction digital subtraction angiography (DSA). For equal detected exposure rates hybrid subtraction had approximately 35% of the SNR of temporal subtraction. When matched filtering was applied to a DSA run, the filtered result had approximately two times higher SNR than the peak contrast image in the run. Thus, when matched filtering techniques were applied to the hybrid image sequence, the resultant SNR increased to about 70% of that of temporal subtraction. With an additional factor-of-two increase in exposure rate for the hybrid run, SNR parity with temporal subtraction could be achieved. This compared with a factor-of-nine increase in exposure that would be required if no filtering were performed. Experimental hybrid matched filter results, generated with intravenous canine DSA studies, supported the predictions in SNR performance.     

Use of DNA hybridizations probes for detection of the plague bacillus (Yersinia pestis) in fleas (Siphonaptera: Pulicidae and Ceratophyllidae)

The detection of active plaque in nature relies primarily on demonstration of the etiologic agent of the disease. Yersinia pestis, in the flea vectors and susceptible mammalian hosts. A live animal assay is currently used for identification of a Y. pestis virulence antigen that is not expressed in the flea. We have found that DNA hybridization probes specific for Y. pestis, used in very simple sample preparation schemes, allow detection of Y. pestis in three species of fleas as well as tissues of experimentally infected mice at minimum concentrations of 1 x 10(6) bacilli/ml. We detected Y. pestis in 22 of 90 (24%) experimentally infected Xenopsylla cheopis (Rothschild), 13 of 25 (52%) Thrassis bacchi (Rothschild), and 9 of 25 (36%) Diamanus montanus (Baker), but no hybridization signals were observed from fleas that had fed on normal mice. The probe technique indicated infection in 9 of 10 potentially infected liver and spleen samples and none of the 5 control samples. Our techniques permit definitive diagnosis in 48 h.