Www.uobabylon.edu.iq



General pathology

Tumors of esophagus:

BENIGN TUMORS

Benign tumors of the esophagus are:

1-Mostly mesenchymal in origin and lie within the esophageal wall. Most common are benign tumors of smooth muscle origin, called leiomyomas. Fibromas, lipomas, hemangiomas, neurofibromas, and lymphangiomas also may seen.

2-Mucosal polyps are usually composed of a combination of fibrous, vascular, or adipose tissue covered by an intact mucosa, so titled as fibrovascular polyp.

3-Squamous papillomas are sessile lesions with a central core of connective tissue and a hyperplastic papilliform squamous mucosa.

MALIGNANT TUMORS

In the United States, carcinomas of the esophagus represent about 6% of all cancers of the gastrointestinal tract. They remain asymptomatic during much of their development and are often discovered too late to permit cure. With rare exception, malignant esophageal tumors arise from the epithelial layer. For many years, most esophageal cancers were of squamous cell origin, but there has been a declining incidence of these tumors coupled with an increasing incidence of adenocarcinomas. Worldwide, squamous cell cancers constitute 90% of esophageal cancers, but in the United States squamous cell carcinoma and adenocarcinoma exhibit comparable incidence rates.

Squamous Cell Carcinoma

Most squamous cell carcinomas occur in adults over age of 50. The male-to-female ratio falls in the range of 2:1 to as high as 20:1. the incidence varies widely among countries. The region extending from Northern Iran across Central Asia to Northern China exhibits high incidence, other areas of high incidence include South Africa, and Eastern Europe. In the United States, squamous cell carcinoma of the esophagus affects 2 to 8 persons per 100,000 yearly and is predominantly a disease of men (male-to-female ratio, 4:1). Blacks throughout the world are at higher risk than are whites, reaching a fourfold higher incidence in the United States.

Etiology and Pathogenesis.

The dietary and environmental factors, with an ill-defined contribution from genetic predisposition are responsible for development of malignant tumors of the esophagus.

The majority of cancers in Europe and the United States are attributable to alcohol and tobacco usage. Nutritional deficiencies associated with alcoholism may contribute to the process of carcinogenesis.

The presence of carcinogens, such as fungus-contaminated and nitrosamine-containing foodstuffs in China, may play a significant role in the high incidence of carcinoma in this region. Dietary deficiencies in vitamins and essential metals have been documented in China and South Africa. Human papillomavirus DNA is found frequently in esophageal squamous cell carcinomas from high-incidence regions.

Finally, the chronic esophagitis so commonly observed in persons living in areas of high incidence may itself be the result of chronic exposure to such carcinogens. This esophagitis results in an increased epithelial cell turnover, which, over a length of time in a continuously carcinogenic environment, progresses to dysplasia and eventually to carcinoma.

Factors associated with SCC of esophagus:

1-Dietary Factors:

Deficiency of vitamins (A, C, riboflavin, thiamine).

Fungal contamination of foodstuffs

High content of nitrites/nitrosamines

2-Lifestyle:

Alcohol consumption

Tobacco use

Urban environment

3-Esophageal Disorders:

Long-standing esophagitis

Achalasia

Plummer-Vinson syndrome

4-Genetic Predisposition

Long-standing celiac disease

Tylosis

Racial disposition

MORPHOLOGY.

20% of these tumors are located in the upper third, 50% in the middle third, and 30% in the lower third of the esophagus. Early lesions appear as small, gray-white, plaquelike thickenings or elevations of the mucosa. In months to years, these lesions become masses and may eventually encircle the lumen. Three morphologic patterns are described:

(1) Protruded (60% ): a polypoid exophytic lesion that protrudes into the lumen.

(2)Flat (15%): a diffuse, infiltrative form that tends to spread within the wall of the esophagus, causing thickening, rigidity, and narrowing of the lumen;

(3)Excavated (25%): a necrotic cancerous ulceration that excavates deeply into surrounding structures and may erode into the respiratory tree.

Clinical Features.

Esophageal carcinoma is insidious in onset and produces dysphagia and obstruction gradually and late. Patients subconsciously adjust to their increasing difficulty in swallowing by progressively altering their diet from solid to liquid foods. Extreme weight loss and debilitation result from both the impaired nutrition and the effects of the tumor itself. Hemorrhage and sepsis may accompany ulceration of the tumor. Five-year survival rates in patients with superficial esophageal carcinoma are about 75%, compared with 25% in patients undergoing curative surgery for more advanced disease and 5% for all patients with esophageal carcinoma. Local and distant recurrence after surgery is common. The presence of lymph node metastases at the time of resection significantly reduces the 5-year survival.

Adenocarcinoma

With increasing recognition of Barrett mucosa, it is apparent that most adenocarcinomas in the lower third of the esophagus are true esophageal cancers, rather than gastric cancers straddling the esophagogastric junction. Accordingly, adenocarcinoma now represents up to half of all esophageal cancers reported in the United States.

MORPHOLOGY.

Adenocarcinomas arising in the setting of Barrett esophagus are usually located in the distal esophagus and may invade the adjacent gastric cardia. Initially appearing as flat or raised patches of an otherwise intact mucosa, they may develop into large nodular masses up to 5 cm in diameter or may exhibit diffusely infiltrative or deeply ulcerative features.

Microscopically, most tumors are composed of mucin-producing glands.

Clinical Features.

Adenocarcinomas arising in Barrett esophagus chiefly occur in patients over 40 years of age, with a median age in the fifties. In keeping with Barrett esophagus, adenocarcinoma is more common in men than women, and whites are affected more frequently than blacks, in contrast to squamous cell carcinomas. As in other forms of esophageal carcinoma, patients usually present because of dysphagia. Progressive weight loss, bleeding, chest pain, and vomiting may occur.

The prognosis of esophageal adenocarcinoma is as poor as that for other forms of esophageal cancer, with less than 30% 5-year survival.

-----------------------

Lect. -9-

Dr. Ali Zeki

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download