Figure 2.23. Left-sided gastric pull-through. Anteroposterior (A) and lateral (B) films of the chest reveal a large air and soft tissue density within the left hemithorax. A CT section just below the level of the left main stem bronchus (C) reveals surgical staples marking the esophagogastric anastamosis of a left-sided gastric pull-through. A film from an upper GI

Figure 2.23. Left-sided gastric pull-through. Anteroposterior (A) and lateral (B) films of the chest reveal a large air and soft tissue density within the left hemithorax. A CT section just below the level of the left main stem bronchus (C) reveals surgical staples marking the esophagogastric anastamosis of a left-sided gastric pull-through. A film from an upper GI

series (D) confirms the presence of the pull-through and better demonstrates the anastamotic integrity. Another CT section (E), more caudal than that in (C), reveals the fluid-filled intratho-racic stomach. The extent of the pull-through is further demonstrated on another film from the upper GI series (F).

Figure 2.23. Left-sided gastric pull-through. (Continued)

examinations do not fill a mucocele. Instead, either CT or MR (with its multiplanar capabilities) imaging can reveal the presence, help identify its cystic nature, and confirm the proteinaceous contents of the muco-cele [78,83,84].

Mucoceles are usually asymptomatic [83]. However, in one series of six patients, five were symptomatic [78]. Three patients suffered from respiratory distress, while two others had pain and nausea. In the former group, the mucoceles were of long-standing duration but were actually the smallest of the mucoceles encountered [78]. One reason for the failure of mucoceles to become symptomatic is masking of symptoms by the underlying disease, which may even lead to the patient's demise before symptoms can develop [83].

If a mucocele is thought to be infected, then CT- or ultrasound-guided aspiration may be performed [78,85,86]. Internal drainage can be performed in patients in whom the isolated esophagus cannot be resected [78]. Rupture of a mucocele leading to a subphrenic abscess has also been reported [87].

Dysphagia is often the symptom that prompts examination of the patient after the acute postoperative phase has passed. Oftentimes that examination reveals an anastomotic stricture. Classically smooth, symmetric, and tapered ending at the level of the esophagogastric anastomosis [66], these strictures are most likely secondary to previous leaks, even undetected, at the level of the anastomosis [67,88]. The type of suture material used for the anastomosis was once thought to be an etiology for stricture formation, but this is no longer thought to be true [89].

In one series, no surrounding mass was noted in cases of benign strictures, but 25% had associated ulcerations, either at or just proximal to the narrowing [66]. These authors reported that in no case was any abnormality found on the gastric side of the anastomosis. As the degree of narrowing increases, a "jet phenomenon" may be observed during esophagography [67]. This may be used to actually measure the degree of anastomotic narrowing. As a rule, CT imaging is not of benefit in following patients with benign strictures [69]. When a stricture is found less than 3 months postoperatively, it usually is benign [71].

The delayed onset of anastomotic leaks can be found in up to 16% of postoperative patients [90]. Half these patients with delayed onset of leaks were asymptomatic with no evidence of fever, chest pain, or other sign of a leak at the time of their examination. Eventually one of these patients developed signs and symptoms of infection. Reexamination showed that the leak had progressed to a gastropleural fistula. Patients who were symptomatic at the time of examination had much more extensive leaks, including gastropleural and gastrobronchial fistulas [90]. Another patient had an esophagogastric fistula paralleling the esophagogastric anastomosis, resulting in a double channel at that level.

When dysphagia occurs more than 3 months postoperatively, tumor recurrence must strongly be considered [71]. When tumor recurs, it may appear locally at the anastomotic site, or it may involve other portions of the gastric pull-through, from contiguous spread from the mediastinum, or even at the site of the pyloroplasty or myotomy [67,69]. Anastomotic recurrence is almost never found at a cervical anastomosis, perhaps because the shorter cervical esophageal remnant affords wider margins of resection [67,91,92]. Yet superior mediastinal adenopathy was much more common in the patients [92]. Recurrent left laryngeal nerve palsy, with its associated vocal changes and possible aspiration, was much more common as well in these patients with high anastomoses [92].

When recurrences are detected at barium studies, the narrowings are often associated with masses at or near the anastomoses [66]. In almost half these patients, the mass effect extends inferior to the level of the anastomosis, unlike benign strictures, in which there is no mass effect. In slightly greater than half these patients, ulceration may occur. The presence of ulceration (Fig. 2.24) is not adequate to differentiate benign from anastomotic recurrence [66]. More important differential features include narrowing below the anastomosis, eccentric narrowing of the lumen, and formation of fistulas [66]. Esophageal-airway fistulas have also been described, and these are often due to necrotic tumor mass and/or radiation therapy administered to treat the recurrence [66].

Most recurrences originate extramucosally [66,69,91] and therefore computed tomography is of significant value in its detection. The CT appearance of recurrence is varied and may include a perianastomotic soft tissue mass (most common), mediastinal soft tissue masses at the level of the original tumor, mediastinal masses above or below that level, or nodular thickening of the gastric wall [91]. Masses at the pyloromyotomy site have also been described [69]. Apparent gastric wall thickening without mass should not be considered to be a sign of recurrence [69].

Figure 2.24. Esophagogastric anastomotic ulcer. Following a gastric pull-through, a film from an upper GI series shows a benign anastomotic ulcer (along with leakage alongside the relocated stomach).

Caveats in the interpretation of CT images include a blind gastric pouch associated with the closure of the cardia, or other gastric out-pouchings, which may present as a soft tissue mass that simulates recurrence on CT imaging unless properly distended by air and/or oral contrast [91]. Wall thickness is also difficult to properly evaluate because the interposed stomach is underdistended. Especially on older generation CT images, artifacts from metal clips in the mediastinum may add to the difficulties encountered [91]. Infiltration of the mediastinal fat may be secondary to inflammation and scar tissue, rather than indicating neoplastic spread [91].

Other areas of recurrent tumor that can be detected by CT imaging include liver metastases, abdominal lymphadenopathy, pleural masses, peritoneal and omental carcinomatosis, and skin and adrenal involvement [69,91]. In a 1987 study, CT imaging served to diagnose distant spread in half of all patients who presented with local recurrence [91].

Vomiting and retrosternal fullness may suggest pyloric narrowing and resultant outlet obstruction of the pull-through. Pyloric stenosis is usually evidenced by a dilated interposed stomach on plain film or CT images (Fig. 2.25A). There is delayed gastric emptying, even with the

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