Ann Pathol
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Serrated polyps of the colorectum are a heterogenous group of mucosal lesions including hyperplastic polyps (HP) and sessile serrated adenomas (SSA), but their morphologic distinction is not always straightforward. However, it is important for the pathologist to identify SSA because recent data show that they might be the precursors of serrated adenocarcinomas which are probably involved in the serrated pathway. ⋯ SSA can be distinguished morphologically from HP in a daily practice. The presence of foci of dysplasia in one case of SSA supports the hypothesis that these polyps have a carcinogenetic potential and should have the same clinical follow-up as traditional adenomas.
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Gastrointestinal stromal tumors (GISTs) are the most frequent mesenchymal tumors of the gastrointestinal tract. Major advances in their definition and classification and the understanding of their molecular mechanisms have recently been made. These advances have resulted in the delineation of a treatment that has become a model of targeted therapy in oncology. ⋯ Prognosis is based on a simple algorithm using two histoprognostic parameters, i.e., tumor size and mitotic index. The treatment of localized GIST is surgical resection, which must be complete; that of advanced or unresectable GIST is based on the use of a targeted therapy, imatinib, which is a pharmacological antagonist of the KIT protein. Proper understanding and utilisation of the diagnostic criteria and classification of GIST by pathologists are essential for good patient management.
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Hirschsprung's disease (1/5000 live births) is defined by the congenital absence of neuronal cells in the nervous plexuses in the distal part of the digestive tract. The disease affects the rectum and sigmoid colon in 80% of cases, or is more extensive. Hirschsprung's disease is suspected in cases of low gastrointestinal obstruction in the neonatal period, or in cases of chronic severe constipation in childhood. ⋯ Different genes (RET, most often) may be involved in sporadic or familial Hirschsprung's disease. Hirschsprung's disease is associated with other digestive or extra-digestive abnormalities in 5 to 30% of patients. Associated abnormalities may delay the diagnosis and treatment of Hirschsprung's disease.
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The diagnosis of drowning is one of the most difficult in forensic pathology. Drowning is death through the aspiration of fluid into the air passages. Signs of immersion only demonstrate submersion of the body for a period of time but are not signs of drowning. ⋯ The diatom test has poor sensitivity and thus is much debated because it is always difficult to rule out possible contamination. Moreover, a negative diatom test cannot rule out drowning as the cause of death. The diagnosis of drowning is based on police investigations, forensic autopsy, microscopic analysis, and biochemical tests, but never solely on pathology findings.
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Mycobacteria species other than members of Mycobacterium tuberculosis complex are called non tuberculous mycobacteria (NTM) or "atypical" mycobacteria. To date, about 80 mycobacterial species have been described. They are usually opportunistic pathogens with variable degrees of virulence. ⋯ Diagnostic criteria involve clinical, radiological, microbiological and pathological findings. Identification of Mycobacterium species in cultures is the gold standard. Pathological examination has several interests: it may reveal an NTM disease, it provides a more rapid assessment of the infection than cultures, and helps to evaluate the virulence of NTM species identified by cultures.