A 39-year-old man was referred to our Echoendoscopy Unit to determine the nature of a submucosal lesion located on the gastric side of the oesophago-gastric junction. The patient began his medical examination in the Otorhinolaryngology Department, where he consulted for pharyngeal discomfort. After the examinations carried out by this department, it was decided to perform an upper endoscopy, where a rounded lesion with preserved mucosa of approximately 1.5 cm in diameter was found at 36 cm from the dental arch. Endoscopic biopsies were taken and the histological results were inconclusive. In the presence of a submucosal lesion, the nature of which could not be identified by endoscopic imaging or after histological study of the biopsies, the patient was referred to our centre for endoscopic ultrasound examination (EUS).
EUS is performed on an outpatient basis, under vital signs monitoring and conscious sedation based on midazolam and pethidine. A Pentax EG3830UX linear echoendoscope coupled to a Hitachi 8500 ultrasound machine was used. At 36 cm from the dental arch, a small, well-defined, anechoic lesion with a cystic appearance was identified, which appeared to be submucosally dependent, measuring 14 x 6 mm in maximum diameter. The ultrasonographic study did not identify the presence of abdominal or mediastinal adenopathies and demonstrated the integrity of the vascular axis. Once the lesion to be punctured has been identified, a colour Doppler ultrasound study is performed to avoid vascular formations and to identify the most suitable route for the puncture. The Echotip Wilson-Cook 19 G needle is used for the puncture. First, the needle sheath is extracted a few centimetres through the working channel until it is visualised either gastroscopically or echoendoscopically; the lesion is then punctured using the needle located inside the sheath. Once its position inside the lesion has been verified, the stylet is removed (which is used to prevent possible contamination of the sample) and the needle is advanced in order to extract as much material as possible from the lesion. In our case we have used an aspiration syringe to increase the cellularity of the sample. Two passes are made over the lesion until the pathologist, present in the examination room, confirms the sufficiency of the sample.

The Diff-Quick stain (Merck) is used to evaluate the sample in the examination room and the cytological study is completed with the Papanicolau stain (Merck). The cytological examination revealed abundant foamy histiocytes and scant cylindrical epithelium indicative of a benign cyst compatible with a gastric duplication cyst.

