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Aims: To establish the prevalence of cyclooxygenase-2 (COX-2) expression in a large series of resected Barrett's adenocarcinoma and associated preneoplastic lesions and to correlate this expression with clinicopathological data and prognosis. Methods: COX-2 expression was assessed by immunohistochemistry in resected surgical specimens of 66 Barrett's adenocarcinomas and 32 cases of Barrett's mucosa (with dysplasia in 17 cases). Results: Epithelial expression of COX-2 protein was increased in Barrett's mucosa compared with normal oesophagus. Epithelial expression of COX-2 was found in 91% of Barrett's specialized mucosa negative for dysplasia, 94% of Barrett's mucosa with dysplasia, and 97% of Barrett's adenocarcinoma. COX-2 expression was significantly higher in the well-differentiated adenocarcinomas when compared with the poorly differentiated tumours. There was no significant correlation between COX-2 expression and the other pathological features of the tumours. Survival analysis showed no significant prognostic value for COX-2. Conclusion: Our results confirm up-regulation of COX-2 in Barrett's oesophagus—metaplastic and dysplastic—and in Barrett's adenocarcinoma. Increased COX-2 expression did not differ during the progression from Barrett's oesophagus negative for dysplasia to Barrett's adenocarcinoma and is related to adenocarcinoma whose histology is well differentiated. This suggests that enhanced expression of COX-2 may occur early during Barrett's-associated neoplastic transformation.

epidural localization is a rare presenting sign of non Hodgkin's lymphoma. In this study, we describe the clinical, histological and immunohistochemical data in 13 cases (9 men and 4 women) of non-Hodgkin's lymphoma with epidural involvement.the median age was 63 years (range 36-76 years). Clinically, most patients complained of back pain (median duration, 3.4 months) followed by acute neurological deterioration. In 10 out of 13 tumors, a thoracic localization was observed and a decompressive laminectomy was performed in all cases. Histology and immunohistochemistry showed all tumors to be B-cell lymphomas which were classified as: lymphocytic lymphoma (3 cases), prolymphocytic lymphoma (1 case), follicular lymphoma (2 cases), diffuse large cell lymphoma (6 cases) and AIDS associated Burkitt lymphoma (1 case). Post-operative staging revealed bone and/or paravertebral involvement in 11 cases and disseminated disease in 5 cases. Median survival following complementary therapy, radiotherapy and chemotherapy in most cases, was 20 months.histological features of epidural lymphomas are similar to other extranodal lymphomas and their prognosis is better than other epidural neoplasms, especially when the tumor is localized.

Arterial endofibrosis is a rare disease usually affecting the external iliac artery in highly trained athletes. We report a case of bilateral external iliac endofibrosis in a 44-year-old cyclist. Microscopic examination of the resection specimen showed an isolated thickening of the arterial intima, and confirmed the diagnosis of this entity of unknown etiology.

Pancreatic neuroendocrine tumors are rare in von Hippel-Lindau disease, most often asymptomatic, nonfunctioning, non secreting, and benign. We report a case of low grade malignant pancreatic, secreting and asymptomatic neuroendocrine tumors, occurring in a 27 year old woman in the setting von Hippel-Lindau disease with recurrent pheochromocytoma, retinal and medullary hemangioblastomas, paraganglioma of the carotid body and ovarian cystadenoma. Neuroendocrine pancreatic tumors of von Hippel-Lindau disease are often constituted by clear cells, in the contrary of other neuroendocrine tumors of the pancreas. Occurrence of a pancreatic neuroendocrine tumor, especially in association with pheochromocytoma, may be misdiagnosed with a type 2 multiple endocrine neoplasia syndrom instead of von Hippel-Lindau disease.

Paragangliomas rarely involve the cauda equina region. In this location, these tumors can show misleading morphological features such as trabecular or papillary growth patterns and variable expression of cytokeratins.We comparatively studied the immunohistochemical and ultrastructural patterns of 3 paragangliomas of the cauda equina (PCE) and of 8 paragangliomas from other sites.All the paragangliomas expressed neuroendocrine markers (neuron-specific enolase, chromogranin A, synaptophysin and neurofilament protein). In PCE, chief cells exhibited a strong positivity with a broad spectrum anti-cytokeratin antibody. The staining was diffuse in the cytoplasm or had a paranuclear dot-like disposition. In other sites, only one paraganglioma showed a focal expression of cytokeratins. At ultrastructural level, chief cells of PCE contained characteristic dense core granules and intermediate-sized filaments sometimes grouped in paranuclear whorls.The dual immunophenotype of PCE, paraganglionic and epithelial, must be recognized in order to distinguish these tumors from, for example, a metastasis of a neuroendocrine carcinoma. PCE are slow-growing tumors and have mostly a favorable prognosis after complete surgical excision.