Importance of mediastinal screening-based observation during endoscopic ultrasound to examine gastrointestinal pathologies

In all EUS examinations performed at our hospital, the mediastinum from the esophagus is observed after checking for gastrointestinal pathologies. The procedure is to first visualize the liver, and subsequently, examine the right atrium from the hepatic vein to the inferior vena cava. Following this, the scope is slightly turned counterclockwise and the left atrium, left ventricle, ascending aorta, pulmonary artery, and the lymph nodes of subcarinal space are observed. Subsequently, the scope is withdrawn and rotated leftward at the site where air was visible through the carina. The aortopulmonary window lymph nodes, aortic arch, and pulmonary artery are then examined. It is important to operate the scope gently during mediastinal observation because the esophagus is limited space compared with the stomach.

Primary cardiac tumor is a rare disease identified in 0.001–0.28% of all autopsies. Approximately, 70% of these are benign, while 30% are malignant. Myxoma is the most common pathology among benign cardiac tumors, commonly occurring in the left atrium. Symptoms include shortness of breath, fainting, and dizziness, which arise due to embolism or hemodynamic disruption caused by mitral valve blockage. There is also a possibility of sudden death if a tumor is affixed to the mitral valve. Echocardiography is useful for diagnosing this condition, in which echogenic luminosity is uneven and sometimes accompanied by calcification. Generally, surgical resection is performed regardless of the tumor size. On the other hands, although aneurysm of the thoracic aorta can cause symptoms such as hoarseness, bloody sputum, and back pain, the majority of cases are asymptomatic. In many cases, the condition is diagnosed by simple chest X-rays or CT examinations for other diseases, with CT examinations being most useful for diagnostic purposes. Once a thoracic aortic aneurysm ruptures, the patient faces a high mortality rate, and surgical treatment must be considered based on the shape of the lesion, size of the aortic aneurysm, rate of expansion, observed symptoms, and other factors. Since saccular aneurysms and pseudoaneurysms are at a higher risk of rupture, surgery is indicated for these conditions. The present case involved a saccular aneurysm, and accordingly surgery was performed as this was the indicated treatment method.

During a literature review, there have been several reports [3‐7] regarding incidental diagnosis of other diseases than the gastrointestinal one. For example, the report by Zalts et al. [3] involved a giant left atrial myxoma discovered unintentionally during examination of a gastric submucosal tumor. The small number of such reports regarding incidentally discovered cardiovascular diseases is probably because of few institutions where mediastinal observation during EUS examinations are actively performed. The number of EUS examinations performed is likely to increase in the future and the number of unintentionally discovered cases of cardiovascular disease during EUS examination is also likely to increase. Two cases out of 317 EUS examinations in our report suggest the importance of observational cardiovascular screening from the esophagus even in cases where EUS is performed to closely examine gastrointestinal disease. Screening of the cardiovascular and mediastinal lymph nodes from the esophagus requires only 1 min approximately. As cardiovascular diseases are often life-threatening, as in the present 2 cases, observational screening of the cardiovascular system from the esophagus should also be performed during EUS examinations just as the pharyngeal region is examined during upper gastrointestinal endoscopy.