Файл: Advanced Imaging of the Abdomen - Jovitas Skucas.pdf

Figure 1.24. Tygon tube perforation (arrow). Most common site of perforation is at the proximal sleeve.

do migrate proximally and distally, although migration is less of a problem with newer stents. Covered stents tend to migrate more often than uncovered stents; on the other hand, tumor ingrowth occurs with uncovered stents. Stent erosion into adjacent tissues is not uncommon, with most perforations occurring at stent ends.

A nitinol stent broke spontaneously shortly after insertion, and another one broke after

Table 1.5. Complications of esophageal stenting

Reflux

Aspiration

Food impaction

Perforation

Benign strictures at stent edges

Esophagorespiratory fistula

Esophagovenous intravasation

Aortoesophageal fistula

Stent migration

Stent fracture

Stent invagination

Stent twisting/torsion

Tumor ingrowth or overgrowth

Massive hemorrhage

Death

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laser therapy for tumor ingrowth, possibly due to thermal overload during laser therapy (77); electrocoagulation and laser use should be used with caution around a stent. Another nitinol stent invaginated after initial expansion and shortened to about two thirds of its length, allowing tumor overgrowth (78).

Endoscopic laser therapy is useful in palliating some of these cancers, and reopening rates of >90% can be achieved. Survival did not differ in patients with stages III and IV squamous cell carcinoma whether they underwent esophagectomy or endoscopic laser therapy (79); patients undergoing laser therapy did have a shorter hospital stay, although sequential retreatments are necessary. Complications of laser therapy include esophagotracheal fistulas and hemorrhage. There have been incidents of procedurerelated mortality. A prospective randomized trial found that in patients with inoperable esophageal cancer dysphagia palliation was substantially better with stenting than with endoscopic laser therapy (80).

Tumor response to radiotherapy or chemotherapy is estimated by measuring residual tumor size. Tumor volume can be calculated from CT scans by combining adjacent measured tumor areas on each 1-cm slice. The accuracy of this method is similar to results obtained from resected tumor weight and water displacement measurements.

Complications of Therapy: A gastroesophageal anastomotic leak is not uncommon after cancer resection. Most of these leaks are detected by a barium study shortly after surgery, and most smaller ones are managed medically and close spontaneously. Larger ones or those not healing with conservative therapy are amenable to esophageal stenting. In one study, immediate leak occlusion was evident after stenting, and clinical healing occurred in 93% of patients, with a median healing time of 6 days (81).

An esophageal mucocele developed after surgical bypass due to continued secretions in the excluded esophagus (82).

Recurrence/Metastasis

Local recurrence manifest as dysphagia and generally implies extensive disease (Fig. 1.25).

ESOPHAGUS

Figure 1.25. Recurrent cancer at gastroesophageal anastomosis. A gastric cardia adenocarcinoma had been resected previously.

Typical metastases are to mediastinal, cervical, and abdominal lymph nodes.

Endoscopic US is an option for early detection of locally recurrent cancer. A study of patients followed by endosonography found that two thirds of patients were still asymptomatic when US detected recurrence (83).

Metastases from an esophageal adenocarcinoma mimicked myositis ossificans (84).

Lymphoma

A primary esophageal lymphoma is rare. Most involvement is secondary, often due to direct spread from mediastinal lymph nodes or stomach. Lymphomas range from polypoid to diffusely infiltrating (Fig. 1.26). An occasional one is primarily intramural and mimics esophageal varices, similar to a varicoid carcinoma.

A lymphoma infiltrating an esophageal squamous cell carcinoma is a rarity; the diagnosis is difficult even for a pathologist because reactive lymphoid infiltration is not uncommon adjacent to a squamous cell carcinoma.

Sarcoma

Some connective tissue tumors are difficult to characterize even with immunohistochemistry, and most authors simply label them as stromal tumors. Whenever possible, however, a specific pathologic diagnosis should be applied to mesenchymal tumors because of differences in therapy and prognosis.

Within the gastrointestinal tract, gastrointestinal stromal tumors (GISTs) are least common in the esophagus and most common in the stomach. These tumors are discussed in more detail in Chapter 2.

Leiomyosarcoma

Although leiomyomas are common in the esophagus, sarcomatous degeneration is not. Most sarcomas present as large bulky tumors varying in size. Their growth rate is variable, although most are slow-growing. The distinction between a leiomyoma and a leiomyosar-

A B

Figure 1.26. Esophageal lymphoma. A: A diffuse infiltrating, ulcerating tumor (arrows) was believed to have been induced by cyclosporin. (Courtesy of Arunas Gasparaitis, M.D., University of Chicago.) B: Recurrent lymphoma presenting as multiple nodules (arrows).

coma is generally made only by the pathologist and even then often with difficulty.

Dysphagia is the usual presentation. An occasional patient manifests with bleeding or pain. Leiomyosarcomas tend to metastasize late in their course.

The vast majority of leiomyosarcomas develop in the esophageal segment containing smooth muscle (i.e., mid-to-distal esophagus). The rare one found more proximally presumably originates either from the vessel wall or muscularis mucosa. Some are sufficiently large that a chest radiograph reveals a mediastinal mass. Squamous cell carcinomas and adenocarcinomas, on the other hand, rarely are sufficiently large at initial presentation to be detected with chest radiography.

Their barium appearance varies from a mostly intramural to a large intraluminal mass. A primarily infiltrating tumor is less common. Larger ones tend to ulcerate. A rare one is pedunculated and occasionally even extends into the stomach. At times a necrotic one communicates with the esophageal lumen, leading to gas and contrast within the tumor.

Computed tomography identifies any exophytic component. These tumors are isointense with skeletal muscle on T1-weighted MRI and hyperintense on T2-weighted MRI.

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Figure 1.27. A carcinosarcoma presents as an expansile intraluminal polyp (arrows). (Courtesy of Arunas Gasparaitis, M.D., University of Chicago.)

Commonly a carcinosarcoma presents as an intraluminal polyp mimicking a fibrovascular polyp (Fig. 1.27).

Other

Although liposarcomas are relatively common throughout the body, they are rare in the esophagus. Some appear polypoid, and imaging suggests a fibrovascular polyp.

A hypopharyngeal liposarcoma grew submucosally into the esophagus (85).

A rare malignant fibrous histiocytoma presents as a soft tissue polyp.

A carcinosarcoma is uncommon in the esophagus. Histologically, these tumors show elements of both squamous cell carcinoma and sarcoma. Histogenesis is believed to involve metaplasia of some carcinomatous cells toward mesenchymal differentiation. Only rarely is a carcinosarcoma a result of simultaneous adjacent tumor development from both epithelial and mesenchymal tissue, identified by distinct immunoreactive and genetic clonalities in the two components.

Melanoma

Melanocytes are normally present in the esophageal epithelium,and primary melanomas develop in the esophagus, albeit rarely. Many esophageal melanomas, however, are metastatic. These are aggressive tumors associated with a poor prognosis regardless of presentation or appearance.

Common presentations are dysphagia or odynophagia; melena is rare.

Primary melanomas range from an exophytic, pedunculated polyp, often bulky, to an infiltrative lesion, generally not obstructing but distending the esophageal lumen (Fig. 1.28). Endoscopic US shows some of these tumors to be smooth-walled, have discrete margins, and have varying echogenicity (86).

Metastatic melanomas tend to be flat and not visualized with barium studies, although CT and US detect any intramural or extrinsic extension.

Figure 1.30. Pancreatic tail carcinoma spreading to paraaortic nodes and invading distal esophagus. This appearance mimics a primary gastroesophageal carcinoma.

are associated with epithelial hyperplasia and undoubtedly are mistaken for squamous cell carcinomas; endoscopic biopsies identify only about half of these tumors.

A number of these tumors are discovered incidentally. The larger ones result in dysphagia. An occasional one ulcerates. Patients range in age from young adulthood onward.

A barium esophagram reveals an intramural tumor. The appearance is similar to that of a small leiomyoma.

Endoscopic US shows a hypoechoic, solid, intramural tumor (90).

Magnetic resonance imaging in a patient with progressive dysphagia revealed a granular cell tumor to be hypointense on T1-weighted images and mildly hyperintense on T2-weighted images (91); homogeneous contrast enhancement was evident.

Carcinoids

Esophageal carcinoids are rare. The literature is somewhat vague when describing these tumors and such terms as atypical carcinoids and esophageal endocrinomas are encountered, with the latter term used to describe a number of endocrine-active tumors.

Webs and Rings

Esophageal webs are thin membranes, 1 to 2mm in diameter, extending completely or partially around the esophageal lumen. Most webs occur singly and are located in the proximal esophagus along the anterior border. Some are part of a benign appearing stricture.

Most smaller webs are incidental findings; more prominent ones are symptomatic (Fig. 1.31). No definite association exists between the remaining esophageal lumen caliber and degree of dysphagia.

Esophageal webs are amenable to balloon dilation; they are readily dilated with 20-mm diameter balloon catheters, a simple and effective therapy.

Figure 1.31. Upper esophageal webs. No underlying disease was found.

Plummer-Vinson Syndrome

A combination of dysphagia, esophageal webs, and iron-deficiency anemia is characterized as the Plummer-Vinson syndrome. Patients are at increased risk of developing a postcricoid carcinoma.

As already mentioned, these webs are readily dilated.

Epidermolysis Bullosa

Epidermolysis bullosa, an inherited autosomalrecessive autoimmune disorder, is characterized by bullous lesions of the skin and bullae, erosions, and ulcerations in the oropharynx and esophagus. Occasionally the esophagus is involved with no cutaneous manifestations. These lesions heal by fibrosis and result in weblike rings.

An association probably exists between epidermolysis bullosa and Crohn’s disease.

These webs are readily balloon dilated, although therapy often results in hemorrhage and further fibrosis.

Pemphigoid

Cicatricial pemphigoid, also known as benign mucous membrane pemphigoid, results in blistering lesions in the skin and mucous membranes. It rarely involves the esophagus, but when present esophageal blistering results in a web-like appearance, usually in the proximal portion. Some webs evolve into single or multiple strictures, and esophageal dilation is necessary.

One patient with cicatricial pemphigoid was also found to have cervical esophageal intramural pseudodiverticulosis (93).

Dilation, at times multiple, is required for dysphasia induced by these webs. Dilation in one patient led to an intramural dissection extending from the cervical esophagus to the esophagogastric junction (93).

Schatzki’s Ring

Occasionally a web-like narrowing is detected at the distant end of the esophagus. Also called lower esophageal ring or mucosal ring, this narrowing contains not only mucosa but also other

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esophageal wall layers; it does not represent the squamocolumnar-mucosal junction. These rings, at most several millimeters in thickness, are believed by some to be secondary to reflux esophagitis, although their precise etiology is unknown. They are more common in adults than in children. Their prevalence is difficult to gauge; many subtle ones are not detected on an esophagram without full distention.

Schatzki’s rings that are less than 12 or 13mm in diameter lead to solid food dysphagia. An associated hiatal hernias is common.

Progressive dysphagia to solid food and acute food impaction are typical presentations; associated esophagitis is common.

These rings are best studied with the esophagus maximally distended with barium and gas. An occasional subtle one is identified only with a barium pill impacting at the ring.

Other Webs

Occasionally recurrent upper esophageal webs and cricopharyngeal muscle spasms are associated with esophageal heterotopic gastric mucosa.

Occasionally multiple esophageal webs are detected in a patient with dysphagia, but no predisposing condition is discovered; a congenital etiology is often ascribed. Although these patients respond to web dilation, dysphagia often recurs.

Motility Disorders/Dilation

Dysphagia and Dysmotility

Dysphagia is a common condition and is routinely encountered in most practices. Anatomic and functional abnormalities are common even in young adults. In patients younger than 30 years with dysphagia, a barium esophagram was able to explain symptoms in 70% (94); findings included achalasia, dysphagia lusoria, esophagitis, esophageal dysfunction, stricture, gastroesophageal reflux, and pharyngeal dysfunction.

A number of dysmotility findings are specific for a particular disorder but some cannot be pigeonholed into a specific category; these are often given such terms as nonspecific esophageal motility disorder or lower esophageal sphincter