Contrast-enhanced ultrasound (CEUS) and CEUS-guided biopsy in the diagnosis of lung abscess in a patient with achalasia: Case report.

Primary achalasia is a rare disorder of unknown aetiology characterized by dysfunction of esophageal motility secondary to degeneration of esophageal neurons. Some diseases, in particular neoplastic diseases, can cause symptoms similar to achalasia, and this condition is called pseudoachalasia. Pseudoachalasia can be indistinguishable from primary achalasia, and many investigations are often necessary to detect or exclude an underlying neoplasia. We report a case in which thoracic contrast-enhanced ultrasound (CEUS) and percutaneous CEUS-guided lung biopsy played a central role in differentiating aspiration pneumonia secondary to achalasia and complicated by lung abscess from pseudoachalasia secondary to lung carcinoma, after computed tomography (CT) yielded inconclusive findings. US contrast agent SonoVue® has an exclusively intravascular distribution, and its ability to discriminate between contrast vascular signal and tissue signal is greater than that of CT, making CEUS superior to CT in distinguishing perfused, viable tissues from avascular necrotic tissues. Although its use in pleuropulmonary pathology is still off-label, CEUS can play a useful role in characterizing peripheral pulmonary masses in selected cases.