Endosonographic (EUS) Diagnosis of Foregut Duplication Cysts

Abstract

Purpose: To highlight the potential for infectious risk of EUS-FNA for these cysts, and to suggest CT and EUS features that can suggest this diagnosis without FNA. Methods: Retrospective case review Results: Foregut duplication cysts are benign, rare anomalies that arise during early embryonic development. They are typically discovered incidentally on radiologic imaging. The diagnosis can usually be made by CT and EUS appearance. EUS-guided FNA has been used to establish the diagnosis of duplication cyst and is considered to have a low risk of infection. Case reports: We describe 3 patients who underwent EUS- FNA for diagnosis of incidental mediastinal lesions, who developed cyst infection requiring surgical treatment, despite prophylactic periprocedure antibiotics. Patient #1 was a 50 y/o male with dyspnea; chest CT showed a 4 cm lesion in the right posterior mediastinum. The CT attenuation was 40 Hounsfield units (HU). EUS showed a well-defined hypoechoic mass, and FNA was done. 5 days after the FNA, the patient developed fever and epigastric pain. Repeat CT showed increased size of the mass with peripheral enhancement. Resection showed an infected bronchial duplication cyst. Patient #2 was a 32 y/o female presenting with epigastric pain; a chest CT showed a well-defined 3.7 cm subcarinal lesion of 42 HU. EUS demonstrated a hypoechoic mass and FNA showed degenerated ciliated cells consistent with an esophageal duplication cyst. Chest pain occurred 5 days after FNA. CT showed increased cyst size with pleural effusions. Resection of an infected cyst was necessary. Patient #3 was a 59 y/o male with a 5.7 cm posterior mediastinal lesion with attenuation of 38 HU. EUS-FNA showed a hypoechoic mass yielding benign squamous epithelium. He subsequently developed fever and chest pain; repeat CT showed increase in size of the cyst with inflammatory changes. Resection was again necessary. Conclusion: CT scans provide valuable information regarding size and location of foregut duplication cysts. These cysts typically have an attenuation value of 0 ± 20 HU. The lesion can have higher HU if there is hemorrhage, proteinaceous material or septations. Typical EUS appearance of duplication cysts are well-defined thin-walled cystic structures that are anechoic or hypoechoic. In the above cases, the CT appearance and location was consistent but attenuation was higher than expected. The EUS appearance was hypoechoic, which prompted the FNA, with negative consequences. At EUS, characteristic location, and hypoechoic but not anechoic appearance may be suggestive of a foregut duplication cyst. Combined CT and EUS appearance may be sufficient in making this diagnosis without FNA and its potential for infectious complication.