الفهرس 
ANATOMY OF THE ESOPHAGUSOnly 14 pages are availabe for public view
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Abstract
Esophageal cancer is a malignancy with a poor prognosis. It is the sixth cause of cancer-related death worldwide. The incidence of esophageal cancer has increased dramatically during the past 3 decades.
Nutritional deficiencies including low level of vit. A, C, riboflavin, mineral elements such as selenium, zinc, molybdenum and high levels of nitrates, nitrites which are converted to N-nitrosamines, alcohol and tobacco use are predisposing conditions, also achalasia, caustic injuries, tylosis, Plummer-Vinson syndrome, Barrett’s metaplasia, gastroesophageal reflux, obesity, H.pylori infection contribute to the pathogenesis of esophageal carcinoma .
History of irradiation has been linked to an increased risk of esophageal carcinoma. The first report that linked radiation therapy with cancer of the esophagus appeared in the early 1960s, when several case reports described cases of esophageal cancer after regional radiation treatment for primary cancers of the head and neck. More recently, several reports described case series observed in various hospitals around the world .
Dysphagia, usually for solids, is the most common presenting feature of esophageal carcinoma. It can progress to dysphagia for liquids and odynophagia. Weight loss inevitably follows and is an adverse prognostic factor. Regurgitation, retrosternal pain, and hoarseness might also occur. Direct invasion of the airway presenting as a tracheoesophageal fistula or invasion into the aorta with fulminant bleeding, although rare, can occur with local progression. Common sites of metastases include the liver, lung, bone, peritoneum, and nonregional lymph nodes. The brain is an uncommon site for spread . The physical examination is usually unremarkable. Lymphadenopathy, particularly in the left supraclavicular fossa (Virchow’s node), hepatomegaly, and pleural effusion are all common indicators of metastatic disease.
Barium swallow is usually the initial diagnostic study obtained and is a crucial diagnostic study in the evaluation of dysphagia to visualize the esophageal mucosa, luminal distensibility, motility and any anatomic abnormalities. Early cancers appear as small intraluminal plaques, polypoid lesions, or areas of discrete ulceration. .Advanced esophageal carcinomas usually appear on barium studies as infiltrating, polypoid, ulcerative, or, less commonly, varicoid lesions
CT, endoscopic US, and PET all play important roles in the staging of patients with esophageal cancer. CT is a good initial screening modality for determining whether the patient may undergo resection or has distant metastases. CT can also help detect enlarged lymph nodes in the mediastinum and celiac region .Endoscopic US is the best modality for determining the depth of tumor invasion and the presence of regional lymph node involvement. Combined use of fine-needle aspiration and endoscopic US can improve the assessment of lymph node involvement. However, PET has the advantage of total body coverage and compared with conventional imaging, PET has been shown to detect distant sites of metastatic disease at initial evaluation. Metastatic disease in distant nodes, liver, lung, bone, adrenal and others detected at initial staging can obviate surgery and affect treatment decisions. PET is useful for assessing distant metastases as well as restaging after neoadjuvant therapy. Therefore, PET can provide additional and complementary information to that obtained by CT . Each modality has its its advantages ; therefore, CT, endoscopic US, and PET should be considered complementary modalities for the staging of esophageal cancer.
Combined functional–anatomic imaging with fused PET/CT is regarded as a further development of the PET technique. PET/CT can help in differentiating pathologic activity from physiologic radiotracer uptake and in localizing the lesion with more legible anatomic details. The routine use of PET/CT in evaluation of patients with esophageal carcinoma is increasing and has been reported to be useful in initial staging of esophageal carcinoma, assessment of therapeutic response after neoadjuvant therapy, and detection of recurrent malignancy. However, accurate interpretation of PET/CT results in patients with esophageal carcinoma requires knowledge of the technical aspects of PET/CT image acquisition and the interpretative pitfalls that may be encountered, as well as an understanding of how the disease manifests and disseminates, the staging criteria used, and the different management strategies available .