At the focal point| Volume 91, ISSUE 5, P1204-1205, May 2020

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Endochondroma of rib showing gastric subepithelial mass-like lesion

Published:December 31, 2019DOI:
      A 54-year-old man visited our outpatient clinic because of a suggestive subepithelial tumor seen during upper GI endoscopy performed for a health checkup at another hospital. On endoscopy (A), an approximately 2-cm round elevated mass with bridging fold was observed in the midbody anterior wall. No specific mucosal abnormalities were observed. The result of endoscopy 3 years earlier was normal, and then the patient had no symptoms, including weight loss. Laboratory findings, including the tumor marker, were also normal. EUS was performed to determine the origin and echogenicity of the lesions. However, there was no subepithelial lesion in the stomach wall (B). Abdominal CT was performed because external compression was suspected. The CT disclosed an approximately 2-cm mass of rib origin, with extrinsic compression of the upper body of the stomach (C, axial view; D, coronal view). It was observed at high density in the precontrast image and was judged to originate from the left seventh rib. To manage the rib mass observed on CT, the patient underwent rib resection. Eventually, histologic examination confirmed endochondroma of the rib. The tumor was composed of mature hyaline cartilage and was adjacent to the normal bone marrow.


      All authors disclosed no financial relationships.
      Commentary One of the main advantages of EUS is the ability to differentiate subepithelial lesions within the gastric wall from external compression. Although it is possible to see external compression clearly on EUS, in several situations the cause of the external compression is not fully revealed. Chen et al reported their experience with 55 submucosal gastric lesions caused by external compression, caused by a normal anatomic structure such as the liver, spleen, or gallbladder in 58% of their cohort. Benign lesions such as liver or pancreatic cysts were the cause of the external compression in 21% of cases. Malignant tumors of the liver, spleen, or pancreas were the cause of the external compression in 5 cases. However, in 6 out of 55 cases, the cause of the external compression was not found, similar to the preoperative experience of the case described here.
      I applaud the authors on performing CT to further investigate the cause of the external compression. Although osteochondroma is a benign cartilaginous tumor, osteosarcoma or other malignant conditions could not have been excluded without surgical resection. This case is a good reminder that a full workup should be performed for gastric submucosal lesions when they are incidentally seen on EGD.
      Mohamed O. Othman, MD, Associate Editor for Focal Points