256 research outputs found
Requiem for the term 'carcinoid tumour' in the gastrointestinal tract?
No full textUse of the term 'carcinoid tumour' to describe a unique type of tumour in the gastroenteropancreatic system is endemic in the medical literature and in daily clinical and pathological parlance. However, it is a somewhat misleading moniker because a spectrum of histopathological changes and hence, biological outcomes may occur in these tumours. The World Health Organization classification scheme recommends the use of the terms neuroendocrine tumours or carcinomas, which may be stratified as well-differentiated neuroendocrine tumours with benign or uncertain behaviour, well-differentiated tumours with low-grade neuroendocrine carcinoma behaviour and high-grade neuroendocrine carcinomas. These categories may be applied within different sites in the gastrointestinal tract and pancreas, and convey a sense of biological behaviour. In addition, a recently suggested tumour-node-metastasis scheme has been proposed and awaits clinical validation and acceptance. Thus, the term 'carcinoid' has served its purpose well, but its use should be phased out in favour of 'neuroendocrine tumour' or 'neuroendocrine carcinoma'
Peripheral nerve sheath tumors of the gastrointestinal tract: a multicenter study of 58 patients including NF1-associated gastric schwannoma and unusual morphologic variants.
No full textThe frequency and morphological spectrum of gastrointestinal peripheral nerve sheath tumors (PNSTs) from consecutive case material has not been studied in the c-KIT era. We reviewed all mesenchymal gastrointestinal (GI) lesions at our departments according to current diagnostic criteria. PNSTs formed the third commonest group of mesenchymal GI tumors with a lower frequency (< or =5%) compared to gastrointestinal stromal tumors (GISTs; approximately 50%) and smooth muscle neoplasms ( approximately 30%). Granular cell tumors (GCTs; n = 31) and schwannomas (n = 22) were the most common types of PNSTs encountered. Rare tumors included neurofibromatosis 1 (NF1)-associated PNSTs (n = 5) and gastric perineurioma (n = 1). Thirteen schwannomas (including also some recent cases) were initially diagnosed as GIST, leiomyoma, or neurofibroma. Unusual histological variants included sigmoid GCT with prominent lipomatous component (n = 1), reticular-microcystic schwannoma of small (n = 1) and large (n = 1) bowel, NF1-associated gastric schwannoma (the first case to date), and psammomatous melanotic colonic schwannoma unrelated to Carney complex (n = 1). PNSTs coexisted with GIST in four patients (three had definite NF1). In conclusion, PNSTs of the GI tract are rare uniformly benign neoplasms that may show schwannian, perineurial, fibroblastic, or mixed differentiation. Most of them (92%) occurred sporadically unassociated with NF1 or NF2. Gastrointestinal PNSTs are still underrecognized by general pathologists. Awareness of their diverse morphology will help to avoid confusing them with smooth muscle neoplasms and GIST that they may closely mimic
A proposal for the classification of follicular-patterned neoplasms of the thyroid gland
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Myxoid perineurioma presenting as a gastric polyp.
No full textA 58-year-old man presented with epigastric pain that was refractory to analgesia. Before this, he was well and did not have manifestations of type 1 neurofibromatosis. Endoscopy revealed a 0.5-cm polypoid antral lesion that was snared and removed in total. Histological evaluation showed a submucosal myxoid spindle-cell proliferation. The tumor was arranged in whorls with distinct concentricity. Within the myxoid stroma, occasional eosinophils were present together with a delicate capillary network. There was no cytological atypia, areas of hypercellularity, or necrosis. The lesion was strongly positive for epithelial membrane antigen and also positive for CD34. All other markers including S-100, desmin, and CD117 were negative. The overall morphological and immunophenotypic features of this lesion are in keeping with a myxoid gastric perineurioma. This lesion needs to be separated from an inflammatory fibroid polyp and a gastrointestinal stromal tumor
p27 Protein and cancers of the gastrointestinal tract and liver: an overview.
No full textGOALS: The purpose of this review is to look at the evidence presented in the literature on the immunoexpression of p27 in cancers of the gastrointestinal tract and liver. BACKGROUND: Cell cycle proteins have been shown to play an important role in the oncogenesis of many tumors. Several of these proteins have been examined in concert and in isolation, and some have been put forward as putative tumor markers. p27, which is an important inhibitory protein in the cell cycle and belonging to a group of cyclin-dependent kinase inhibitors, has also been studied in several malignancies, most notably breast, lung, bladder, and prostate cancers. Considerable work has also been done on the expression of this protein in cancers occurring within the gastrointestinal tract. RESULTS: Cancers occurring in the major sites of the gastrointestinal tract (esophagus, stomach, and colorectum) and liver show a similar pattern with regard to p27 protein levels. p27 emerges as a statistically significant predictor of survival and tumor behavior. It has been suggested that p27 loss occurs early in the carcinogenesis process, with dysplastic epithelium having decreased expression. The more aggressive, metastasizing cancers tend to lack p27 expression as well. Some studies have also invoked the subcellular localization of p27 (cytoplasmic versus nuclear) as also being of prognostic value. CONCLUSION: Therefore, in gastrointestinal and hepatic cancers, low p27 expression is regarded as an important adverse prognostic factor
Cyclin E and p27: Their putative role as prognostic markers
No full textAbnormalities or derangements of the orderly proliferation and cycling of cells is the quintessential definition of a cancer or malignant cell. The complex nature of the interaction of several interdependent cell cycle proteins has and continues to be unravelled. Key functions have been ascribed to many of the proteins and the delicate balance that maintains cell normal cell cycling is now understood. Within the cell cycle, the GI proteins have come under intense scrutiny, especially the interaction between cyclin E and p27. Essentially, cyclin E drives the cell cycle forward towards mitosis, while p27 acts as a brake preventing cell cycle progression. The levels of these two proteins, independently and together, have been analysed in many studies in several tumour types. A pattern or trend has emerged: high cyclin E with low p27 is an adverse prognostic indicator in the majority of commonly encountered malignant tumours. Furthermore, in several instances, there is a stepwise increase of cyclin E and decrease of p27 that matches the progression from dysplastic, pre-invasive lesions to full-blown invasive malignant tumours. As a cautionary note, there are exceptions to this tenet as exemplified by bladder and oesophageal cancers, where the relationship between cyclin E and p27 is not straightforward. The body of evidence in the literature points to both cyclin E and p27 as being useful adjuncts to prognostication indices, but not unreservedly as independent portenders of outcome. © 2002 Elsevier Science Ltd
Pancreatic endocrine neoplasia: familial syndromes
No full textInherited or familial neuroendocrine tumours of the pancreas are uncommon. The most frequently encountered syndromic form occurs in the setting of multiple endocrine neoplasia type 1 (MEN-1). Sixty per cent of patients with MEN-1 manifest pancreatic endocrine tumours (PETs). These tumours occur in younger patients and tend to be more aggressive than similar sporadic forms. The pancreas displays a range of morphological changes that can assist in making the diagnosis of MEN-1. Ductulo-insular complexes, islet dysplasia and multiple non-functioning microadenomas are typically encountered. If functional, the tumours tend to be gastrin producing. von Hippel-Lindau patients can also have PETs, although benign cysts and serous microcystic adenomas are commoner. Multiple tumours may be encountered and they are characterized by cells with lipid vacuoles. PETs may also be seen in patients with type 1 neurofibromatosis (NF-1) and they are usually somatostatin producing. PETs are less frequently encountered than duodenal tumours in the setting of NF-1. Very few cases of PET are seen in tuberous sclerosis. © 2009 Elsevier Ltd. All rights reserved
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