Pathologies pulmonaire et cardio-vasculaire

1re édition 1993-1994/1MEDinfo:eu-repo/semantics/published

Dysplasie de l'epithelium pavimenteux oesophagien

Dysplasia can be defined as a preneoplastic lesion characterized by tissular architectural anomalies and cytological changes which remain confined to the epithelium. After a short description of the different histological and cytological criteria of esophageal squamous dysplasia, the authors review the old classifications in three grades: mild, moderate and severe and their evolution towards a simplified two tier classification in low and high grade. The evidence of an association between dysplasia and cancer and the role of dysplasia in esophageal carcinogenesis rely upon several types of studies: epidemiological (geographical and follow-up studies) as well as morphological (based on detailed investigations of surgical specimens). Although esophageal dysplasia is rare in our countries, in populations at risk, taking into account its excellent prognosis, a rigorous screening methodology must be used associating endoscopic vital staining with cytology and histology.SCOPUS: re.jinfo:eu-repo/semantics/publishe

Aspects macroscopiques et microscopiques des cancers oesophagiens

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La dysplasie dans les lesions polypoides et planes du colon

The term polyp applies to any intraluminal projection whatever its nature. Among polyps derived from the epithelium, adenomas are distinguishable by their modified dysplastic epithelium. Three types are recognized: tubular, villous and tubulo-villous. Besides these classical forms, two different lesions have been described more recently: serrated adenomas which share the features of hyperplastic polyps and tubular adenomas that behave as the latter. Flat adenomas cannot strictly be considered as polyps. They are slightly surelevated lesions; histologically they correspond to tubular adenomas. Dysplasia in adenomas can be graded as in any other tissue as mild, moderate and severe or as low and high grade. The severity of dysplasia as well as the cancer risk depend on the size of the adenomas and on their content in villous structures. New techniques complementary to histology such as histochemistry of mucins, immunohistochemistry, demonstration of oncogenes and DNA measurements by flow cytometry or by image analysis can contribute to a better understanding of carcinogenesis; their practical use is nevertheless limited. Pathological analysis of polyps must be performed on correctly oriented specimens to answer the question: has the resection been curative or not? The prognosis and further treatment of the adenomas depends more on the detection of carcinomatous foci than on the degree of dysplasia.SCOPUS: re.jinfo:eu-repo/semantics/publishe

Relation entre le lymphome gastrique du MALT et l'Helicobacter pylori: Le point de vue du pathologiste

Recent studies implicate Helicobacter pylori in the pathogenesis of gastric MALT lymphomas. Epidemiological studies show the high prevalence of lip in patients operated on for gastric lymphoma. Histopathological data demonstrate similarities between chronic Hp + gastritis and gastric MALT lymphomas. They highlight the constant presence of lymphoid follicles in both entities and the existence of lympho-epithelial complexes, considered as typical of MALT lymphomas, in some cases of Hp+ gastritis. Additional proof comes from therapeutic studies indicating that most low grade MALT lymphomas regress under antibiotic treatments which eradicate Helicobacter pylori. Although these data have led to a new therapeutic approach, more research is needed since regression only occurs in superficial tumours restricted to the mucosa or the submucosa and is never observed in extended lesions nor in high grade lymphomas.SCOPUS: re.jinfo:eu-repo/semantics/publishe

Polypes coliques: Criteres de degenerescence et de polypectomie therapeutique

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Lymphome gastrique du MALT et Hp

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A propos de quelques pseudotumeurs du tractus digestif

Non neoplastic lesions presenting as pseudotumoural masses, nodules or polyps can be found at any level of the digestive tract. They can have different origins: hereditary, congenital inflammatory or mechanical. Peutz-Jeghers lesions represent a good example of hereditary pseudotumours; they are covered by an epithelium indigenous to the site where they develop. Juvenile polyps can be solitary or part of a hereditary disorder. Congenitally misplaced tissues occur by cellular entrapment during embryonic reshaping. They can be pancreatic, gastric or more rarely bronchial. Pancreatic ectopias are quite common in the stomach and small intestine including Meckel's diverticula. Their diagnosis is straightforward when acinar or endocrine tissue is present. Problems occur when they are limited to ducts. In the stomach itself, gastric ectopias give rise to small submucosal nodules. The inflammatory fibroid polyps represent an example of pseudotumoural inflammatory lesions. They are mostly seen in the gastric antrum and in the small intestine where they can induce intussuception. The digestive tract shares with the bladder the astonishing capacity to form during regenerative processes an exuberant endothelial and myofibroblastic tissue mimicking on biopsy a sarcoma or even a carcinoma. Solitary ulcer syndrome due to mechanical causes such as mucosal prolapse, is not restricted to the rectum and can be seen higher in the colon as cap polyps or in the anus as cloacogenic polyps. A correct diagnosis is based on a conjunction of several histological changes. Hyperplastic polyps are frequent in the colon where they must be distinguished from neoplastic polyps. In the stomach they occur mostly in the antrum and can be multiple. They are formed by hyperplastic foveolae and inflammatory chorion. Fundic gland polyps were first described in familial adenomatous polyposis but they can be sporadic. They are small sized, often multiple lesions of uncertain pathogeny. A relation to omeprasole therapy has been suggested by some authors.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Pathologie infectieuse de l'estomac: Helicobacter pylori et autres germes

Helicobacter pylori represents the overwhelming part of gastric infectious pathology leaving far behind all the other bacteria. After a short acute phase, most Hp gastritis evolve on a chronic mode. Their main histological characteristics are made of epithelial degenerative and regenerative alterations and cellular inflammatory response of the lamina propria. The lesions can be graded according to the Sydney System (revisited Houston from 1994). The detection of Hp can rely upon special stains such as Giemsa or Cresyl Violet. Immunocytochemistry can be helpful when the germs are scarce (some acute gastritis, after antibiotic treatment…). Another much less frequent Helicobacter is Helicobacter heilmannii which probably results from contaminations by pets and produces lesions very similar to those of Hp. CMV can be observed in immunocompetent as well as immunodeficient hosts; it induces a variety of lesions, sometimes mimicking cancer. Various fungi can localise to the stomach mostly in necrotic tissues from cancers or ulcers. In immunodeficient patients, the lesions can extend to various systems. The other germs, sometimes observed in the stomach, either bacterial, fungal or parasitic are quite rare.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Critères de dégénérescence du polype colique et polypectomie thérapeutique

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