Endoscopic Ultrasonography-guided Fine-needle Aspiration Cytology Combined with a Cell-block Method for Gastrointestinal Subepithelial Lesions.

Introduction The diagnostic accuracy of an endoscopic ultrasound-guided fine-needle aspiration cytology/biopsy combined with a cell-block method (FNA-CB) for gastrointestinal subepithelial lesions (GI-SELs) has not been fully studied. Methods A total of 109 patients (with 110 GI-SELs) were evaluated to clarify the rate of obtaining evaluable histology specimens using FNA-CB. In addition, we investigated the following: 1) the accuracy for determining the histology, 2) effects of the number of cell clusters obtained via FNA-CB, 3) correlation of the Ki67 labelling index (Ki67LI) of the gastrointestinal stromal tumor (GIST) lesions between FNA-CB and resected specimens, and 4) clinical courses for patients followed up after FNA-CB. Results Of the 110 GI-SELs for which FNA-CB was performed, 95 (86%) were able to be histologically evaluated using the first FNA-CB. For the 70 resected GI-SELs, the accuracy of FNA-CB to determine histology was 96%, remaining at 90% even when only a few cell clusters were obtained. The concordance rate of the risk-grouping of GIST (high-risk, Ki67LI ≥8; low-risk, <8) between FNA-CB and resected specimens was 84%. Of the 29 patients followed up after the first FNA-CB, 12 with benign GI-SELs determined using the first FNA-CB showed no obvious increases in their GI-SEL sizes. Conclusions Since FNA-CB can be used to determine the histology and reproductive activity of GI-SELs accurately, not only preoperative histological confirmation but also reliable information to determine clinical plans, such as follow-up without surgery or neoadjuvant chemotherapy, can be obtained.