Diagnosis of Subepithelial Lesion: Still "Tissue Is the Issue"

an elevated lesion covered with normal mucosa is observed during endoscopy, the endoscopist would be suspicious of the presence of a mass underneath the mucosa and calls it a subepithelial lesion (SEL). However, SEL may be a true intramural mass underneath the mucosa or an extralumi-nal compression mimicking an intramural mass. For the evaluation of SEL, endoscopic ultrasonography (EUS) is considered as the best modality. EUS can differentiate between true intramural mass and extramural lesion accurately. 1 In case of true intramural lesions, presumptive diagnosis is possible by an educated guess based on the information obtained from EUS examination. EUS allows endoscopists to examine the size, echogenicity, and layer of origin of the SEL. SELs such as lipoma or cyst can be diagnosed accurately and easily by EUS due to their characteristic hyperechoic or anechoic echo findings , but hypoechoic lesions originating from 3rd and 4th wall layers cannot be accurately diagnosed by EUS findings only. As a result, accuracy of EUS in diagnosis of SEL was reported as 45.5% to 78.4%. At this point, " tissue is the issue " for the definite diagnosis of SEL. EUS-guided fine needle aspiration (EUS-FNA) is one of the ways of tissue acquisition for a definite diagnosis. EUS-FNA is frequently performed to get tissue for pathologic diagnosis of any mass accessible with EUS. However, diagnostic yield of EUS-FNA is poor for SEL compared to mediastinal lymphad-enopathy or pancreatic mass. Diagnostic accuracy of EUS-FNA for SEL has been ranging from 60% to 80%. 4 In this issue of Clinical Endoscopy, Çağlar et al. the diagnostic accuracy of EUS-FNA for SEL as 98.2%, which is unbelievably high. Authors performed EUS-FNA from 67 patients. Among them, adequate specimen was not able to be obtained in nine (13.45%) cases. Subsequently diagnostic yield of EUS-FNA was 85.5%. They reported that the concordance of EUS-FNA with final diagnosis was 98.2% when enough diagnostic material was obtained. However, with close look into the paper, you may find that final pathologic diagnosis was obtained only from 35 of 67 patients and final diagnosis of the other 32 patients was just assumed with endoscopic follow-up. In addition, they merely classified the diagnosis of EUS-FNA into benign and malignant and compared them to final diagnosis to find out diagnostic accuracy. It seems to be necessary to directly compare the actual EUS-FNA diagnosis to final pathologic diagnosis among 35 pathologically proven cases to calculate …