Pseudoachalasia (a.k.a. secondary achalasia) is an achalasia-pattern dilatation of the esophagus due to the narrowing of the distal esophagus from causes other than primary denervation. One of the most common causes is a malignancy (often submucosal gastric cancer) with an extension in the lower esophagus. The clinical and imaging similarities of achalasia and pseudoachalasia may pose a diagnostic challenge, usually requiring further investigation.
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Clinical presentation
The clinical course of pseudoachalasia depends on the underlying cause; however, it, in particular, if secondary to the neoplasm, is usually short (<6 months), unlike the chronic clinical history in patients with primary achalasia. Patients also tend to be older (>50 years) than those with primary achalasia.
Pathology
Etiology
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esophageal malignancy
gastric carcinoma (of the cardia and fundus)
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central and peripheral neuropathy
brainstem infiltration, e.g. malignancy, amyloidosis
infiltration of the vagus by malignancy
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ischemia
acid/alkali ingestion
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the patulous esophagus in some presentations of scleroderma may lead to chronic severe reflux and the development of a distal esophageal stricture
this patient population is also at risk for esophageal carcinoma
The pathophysiology of pseudoachalasia is thought to be twofold:
obstruction of the lower esophagus due to tumor proliferation
tumor infiltration, denervation, or nerve malfunction of the neuromyenteric plexus (of Auerbach), thus creating functional obstruction similar to achalasia
Although less common, it is possible for primary achalasia and malignancy to coexist.
Radiographic features
The plain chest film and barium swallow findings are similar to achalasia and may also show other features of the underlying cause (listed above).
Two useful discriminators in barium swallow, particularly in cases secondary to underlying neoplasm, are
more marked mucosal irregularity of malignant lesions in pseudoachalasia
the temporary patency of the lower esophageal sphincter if the hydrostatic pressure is increased in achalasia
CT is usually the imaging modality of choice for equivocal cases because it more clearly depicts a malignant lesion, as well as potential lymph node involvement, local invasion, or metastatic spread.