Abstract
Background/Aims
Heparinized wet suction (HEP) and the single-pass single-needle actuation method (HEP1p1a) are promising for endoscopic ultrasound-guided tissue acquisition (EUS-TA) because they improve specimen quality. However, its applicability in the biopsy of subepithelial lesions (SELs) remains unexamined. Therefore, this study evaluated the clinical utility of EUS-TA using HEP1p1a in SELs.
Methods
This study analyzed data of patients who underwent EUS-TA using HEP1p1a between January 2019 and May 2025. The primary outcome was pathological differentiation. Furthermore, clinical data of EUS-TA using HEP1p1a were compared with those using HEP and other than 1p1a; subgroup analysis was performed comparing the clinical outcomes between SELs ≥20 and <20 mm.
Results
Thirty-six patients underwent EUS-TA using HEP1p1a (technical success rate: 100%): 24 and 12 patients with lesions ≥20 and <20 mm, respectively. The rates of achieving pathological differentiation, immunohistochemical success, and definitive histologic diagnosis were 94.4%, 89.3%, and 86.1%, respectively; for SELs ≥20 mm, they were 100%, 94.7%, and 95.8%, respectively. Cellularity and maximum length of white sequential specimens were better in patients with lesions ≥20 mm. No adverse events were observed during or after the procedures.
Conclusions
High diagnostic performance and specimen quality were demonstrated with EUS-TA using HEP1p1a for SELs, particularly those >20 mm. To acquire high-quality specimens while minimizing blood contamination, EUS-TA with HEP1pla for SELs might be an effective approach.
Keywords: Biopsy, fine-needle; Endoscopic ultrasound-guided fine; Gastrointestinal stromal tumors; Heparin; Needle aspiration; Suction
Graphical abstract
INTRODUCTION
Subepithelial lesions (SELs) are of various types, and accurate diagnosis is crucial for determining the appropriate treatment strategy. Particularly, gastrointestinal stromal tumors (GISTs) can be malignant; therefore, accurate differentiation is crucial for treatment decision-making. However, distinguishing GISTs using noninvasive imaging, endoscopy, or endoscopic ultrasound (EUS) remains challenging.1-3 Therefore, EUS-guided tissue acquisition (EUS-TA) has become an indispensable diagnostic tool for managing SELs.4 EUS-TA is generally considered unnecessary for SELs measuring ≤20 mm, unless EUS features suggest malignancy. Therefore, EUS-TA is regarded as an important tool primarily for determining approaches for managing SELs >20 mm.5-7 However, even among SELs measuring ≤20 mm, some cases are diagnosed as GIST by histopathology, in which case surgical resection may be indicated. Furthermore, as the usefulness of EUS-TA for SELs ≤20 mm has also been reported, the need to perform this procedure for such small lesions remains controversial.8
EUS-TA was developed to differentiate benign from malignant lesions outside the gastrointestinal mucosa, including SELs, pancreatic lesions, liver lesions, and lymph node tumors.7 EUS-guided fine-needle aspiration (EUS-FNA) needles have been used primarily for cytological diagnosis. However, advancements in needle design have led to the development of EUS-guided fine-needle biopsy (FNB) needles, which have facilitated the histological diagnosis of specimens obtained by EUS-TA.9-14 Furthermore, recent reports have suggested that obtaining a larger volume of tissue allows for additional analyses, such as immunohistochemistry and genomic analysis.13
To increase tissue yield, improvements in puncture needles and techniques have been made and are considered effective, for example, using thicker needles and multiple actuations with the fanning technique in a single pass.15-19 However, single-pass single-needle actuation has reportedly been sufficient,20-22 because excessive actuation in a single pass may increase the risk of blood contamination, tissue damage, and complications. To the best of our knowledge, no previous studies have assessed the optimal number of punctures required for tissue acquisition in SELs. Upon demonstration of the safety of EUS-TA with heparinized saline priming and diagnostic equivalence of single-pass single-needle actuation to multiple actuations, this technique may be regarded as a promising method for obtaining high-quality specimens with minimal blood contamination. Therefore, this study aimed to evaluate the effectiveness and safety of EUS-TA using heparinized wet suction and a single-pass single-needle actuation method (HEP1p1a) for SELs. In a subgroup analysis, we also evaluated the performance of EUS-TA with HEP1p1a in SELs >20 mm, as recommended by the current guidelines.5-7
METHODS
Study design
This single-arm, single-center, retrospective study was approved by the appropriate review board (approval number: 2024-43). The patients were provided with the opportunity to opt out of the study on the hospital’s website. All EUS-TA procedures were performed after informed consent was obtained.
Patients and data collection
All patients who underwent EUS-TA for SELs between January 2019 and May 2025 were enrolled. The data of patients who underwent EUS-TA for HEP1p1a were analyzed. Patient characteristics, including age, sex, target organs, lesion diameter, needle type, number of EUS-TA sessions, and suction-negative pressure, were collected from medical records and endoscopic findings.
The primary outcome was the diagnostic accuracy for determining whether lesions were benign or malignant based on the histopathologic assessment of specimens obtained by EUS-TA with HEP1p1a. The secondary outcomes included technical success rates, success rates of definitive histological diagnoses, immunohistochemistry success rates, and adverse events. In a subgroup analysis, the clinical data of patients with SELs >20 mm were compared with those who did not meet this criterion. Furthermore, as exploratory reference data, this study presented the outcomes of the HEP non-1p1a cohort (heparinized wet suction, single pass with several actuations) as a comparator within the HEP strategy.
EUS-TA procedure
A linear echoendoscope (UCT-260; Olympus Optical) was used in all cases. Either a Franseen-shaped (Acquire, Boston Scientific Corporation; SonoTip TopGain, Medi-Globe) or a tri-tip-shaped (Trident Needles Biopsy System; Micro-Tech) FNB needle was selected for tissue acquisition; the needle gauge was determined at the discretion of the endoscopist. All procedures were performed by experts (>5 years of EUS-TA experience) or trainees (≤5 years of EUS-TA experience).
The stylet was removed from all patients, and the needle was primed with heparinized saline before puncture. A single-pass single-needle actuation method was employed. Following a single deep puncture of the SELs, 10 mL of negative pressure was applied while withdrawing the needle from the surface. The needle was withdrawn without applying negative pressure. Rapid on-site evaluation (ROSE) was not performed. Instead, the success of the procedure was assessed via macroscopic on-site evaluation (MOSE), and the procedure was concluded once an adequate amount of whitish specimen was visually confirmed (Supplementary Video 1, Fig. 1).20 Typically, two or three punctures were performed, with a maximum of approximately five punctures. In cases in which tumor puncture was technically difficult, or MOSE failed to yield sufficient whitish specimens, a transition to mucosal incision-assisted biopsy (MIAB) was considered in the latter part of this study (Fig. 2). The procedure was concluded after confirming the absence of endoscopically apparent needle tract bleeding in the mucosa and abdominal cavity. In the HEP non-1p1a group, most cases were managed using a single pass and five actuators.
Fig. 1.
Histological images of the specimen obtained in the case depicted in Supplementary Video 1 Panels (B–H) show microscopic views at 100× magnification. (A) Macroscopic image. The specimen measured over 3 cm in length. (B) Hematoxylin and eosin staining. (C) C-kit immunohistochemistry. (D) CD34 immunohistochemistry. (E) DOG1 immunohistochemistry. (F) Desmin immunohistochemistry. (G) S-100 immunohistochemistry. (H) Ki-67 immunohistochemistry.
Fig. 2.
Mucosal incision-assisted biopsy (MIAB) for a 5-mm lesion, where endoscopic ultrasound-guided tissue acquisition was challenging. (A) Endoscopic image of the lesion before MIAB. (B) Mucosal incision for the gastric mucosa using a needle knife. (C) Biopsy using forceps targeted at the tumor exposed by the mucosal incision. (D) The biopsy site was closed with endoscopic clips following biopsy.
Definition
Diagnostic accuracy for distinguishing benign from malignant lesions was defined as the ability of EUS-TA to provide a definitive pathological diagnosis or differentiate between benign and malignant lesions, which is sufficient to determine the treatment indication. Pathological diagnoses were defined as malignant if identified as GIST, adenocarcinoma, carcinoma, or malignant lymphoma, and as benign if diagnosed as leiomyoma, lipoma, neurofibroma, schwannoma, ectopic gastric mucosa, or ectopic pancreas. A diagnosis of malignancy was clinically defined when the clinical course was consistent with a histological diagnosis of malignancy or when malignancy was confirmed in a postoperative specimen. Conversely, lesions were defined as benign when the postoperative specimen was confirmed as benign or when malignancy was ruled out after a follow-up period of at least 1 year. Lesions that could not be definitively diagnosed as benign or malignant according to these definitions were considered indeterminate and were excluded from the diagnostic accuracy analysis.
Biopsy was considered technically successful when the target lesion was punctured, and a specimen was obtained using EUS-TA. Immunohistochemistry was not performed in all cases; it was performed only when the pathologist deemed it necessary to establish a definitive histological diagnosis. Among cases in which immunohistochemistry was planned, those in which the staining was deemed feasible were considered to achieve “success of immunohistochemistry.” A definitive histological diagnosis was defined as a histology-based diagnosis established using EUS-TA, with or without immunohistochemistry, as deemed necessary by the pathologist.
Adverse events were evaluated according to the lexicon developed by the American Society for Gastrointestinal Endoscopy workshop and categorized as intraoperative, early (within 14 days), or late (after 14 days) adverse events.21
The quality of the EUS-TA specimens was assessed with reference to a previous report by Chen et al.22 Specimen quality was originally evaluated based on three components—blood contamination, cellularity, and tissue integrity— scored from 0 to 2 to calculate the total score. At our institution, only the macroscopic white tissue core was separated, formalin-fixed, and subjected to pathological evaluation; therefore, blood contamination was negligible. Accordingly, the cellularity and tissue integrity were evaluated, and the maximum white core length was measured.
Tissue integrity was scored as follows: 0, no architecturally intact tissue present; 1, 1–2 architecturally intact tissue present; and 2, ≥3 architecturally intact tissue present. Cellularity was scored as follows: score 0, <10 per high-power field (HPF); 10 per HPF≤score 1<50 per HPF; and score 2, ≥50 per HPF. The maximum white-core length was defined as the longest white-tissue core obtained.
Statistical analysis
Continuous variables were expressed as means (standard deviation) or medians (interquartile range [IQR]), and categorical variables were expressed as numbers (percentages). All statistical analyses were performed using IBM SPSS Software for Windows ver. 29.0 (IBM Corp.).
Ethical statements
This study was approved by the appropriate review board (approval number: 2024-43). The study was conducted in accordance with the principles of the Declaration of Helsinki (revised 2024).
RESULTS
Patient characteristics
During the study period, 64 patients at our institution underwent EUS-TA for SELs. Of these patients, 54 underwent EUS-TA with HEP. Among them, 36 underwent EUS-TA using HEP1p1a and 18 underwent EUS-TA using HEP non-1p1a. Of these, 24 involved EUS-TA for SELs of >20 mm (Fig. 3). The median age of 36 patients who underwent EUS-TA with HEP1p1a was 66 years (IQR, 51.8–76.3), with 20 (55.6%) male patients. The target organs for puncture were the esophagus in five patients (13.9%), the stomach in 24 (66.7%), and the duodenum in seven (19.4%). The median lesion size was 20.5 mm IQR, 15–31.3 mm) (Table 1). Baseline characteristics of patients with SELs ≥20 mm and those with SELs <20 mm, including the baseline characteristics of patients who underwent EUS-TA HEP non-1p1a, are summarized in Table 1.
Fig. 3.
Schematic representation of this study. Endoscopic ultrasound-guided tissue acquisition (EUS-TA) was performed on 36 patients enrolled during the study period. Among these, 64 cases involved EUS-TA of subepithelial lesions (SELs). After excluding cases in which the needle was not primed with heparinized saline or in which the procedure was technically difficult, 54 cases remained. Of these, 36 cases in which a single-pass single-needle actuation was performed were included in the final analyses. HEP, heparinized wet suction.
Table 1.
Characteristics of the patients
| Characteristic | EUS-TA with HEP 1p1a | EUS-TA with HEP non-1p1a (n=18) | p-value (1p1a vs. non-1p1a) | |||
|---|---|---|---|---|---|---|
| All patients (n=36) | Patients with SELs ≥20 mm (n=24) | Patients with SELs <20 mm (n=12) | p-value (≥20 vs. <20 mm) | |||
| Age (yr) | 66 (51.8–76.3) | 69 (54.8–76.3) | 56.5 (50.3–66.5) | 0.25 | 59.5 (54.3–74.8) | 0.66 |
| Sex, male | 20 (55.6) | 15 (62.5) | 5 (41.7) | 0.30 | 8 (44.4) | 0.57 |
| Target organs | 0.29 | 0.86 | ||||
| Esophagus | 5 (13.9) | 2 (8.3) | 3 (25.0) | 2 (11.1) | ||
| Stomach | 24 (66.7) | 18 (75.0) | 6 (50.0) | 12 (66.7) | ||
| Duodenum | 7 (19.4) | 4 (16.7) | 3 (25.0) | 4 (22.2) | ||
| Lesion diameter (mm) | 20.5 (15–31.3) | 30 (20.8–35.5) | 13.5 (12.0–15.0) | <0.001 | 15 (13.5–20.0) | 0.02 |
| Needle types | 0.32 | 0.13 | ||||
| Acquire | 16 (44.4) | 9 (37.5) | 7 (58.3) | 8 (44.4) | ||
| TopGain | 12 (33.3) | 10 (41.7) | 2 (16.7) | 2 (11.1) | ||
| Trident | 8 (22.2) | 5 (20.8) | 3 (25.0) | 8 (44.4) | ||
| Needle gauge | 0.03 | 0.79 | ||||
| FNB 19-G | 15 (41.7) | 13 (54.2) | 2 (16.7) | 6 (33.3) | ||
| FNB 22-G | 20 (55.6) | 11 (45.8) | 9 (75.0) | 11 (61.1) | ||
| FNB 25-G | 1 (2.8) | 0 | 1 (8.3) | 1 (5.6) | ||
| No. of passes | 3 (2–4) | 3 (2–4) | 3 (3.0–4.5) | 0.32 | 3.5 (2.3–4.0) | 0.95 |
| Physician, expert | 23 (63.9) | 16 (66.7) | 7 (58.3) | 0.72 | 9 (50.0) | 1 |
| MIAB | 1 (2.8) | 0 (0) | 1 (8.3) | 0.33 | 2 (11.1) | 0.26 |
Values are presented as median (interquartile range) or number (%).
EUS-TA, endoscopic ultrasound-guided tissue acquisition; HEP, heparinized wet suction; 1p1a, single-pass single-needle actuation; SEL, subepithelial lesion (Acquire, Franseen-tip needle; Boston Scientific); TopGain (Franseen-tip needle, Medi-Globe; Achenmuhle); Trident (tri-tip-shaped, Micro-Tech); subepithelial lesion; FNB, fine-needle biopsy; MIAB, mucosal incision-assisted biopsy.
In all 36 patients, the needles used for puncture were Acquire in 16 patients (44.4%), TopGain in 12 patients (33.3%), and Trident in eight (22.2%). The needle gauges were 19-gauge in 15 patients (41.7%), 22-gauge in 20 (55.6%), and 25-gauge in one (2.8%). The median number of puncture attempts was 3 (IQR, 2–4). MIAB following EUS-TA was performed in one patient (2.8%) owing to inadequate specimen collection.
Clinical outcomes
The technical success rate was 100% for all SEL sizes. Pathological differentiation between benign and malignant tumors, the primary endpoint of this study, was achieved in 94.4% of the patients. The success rate of immunohistochemistry was 89.3% (25/28 patients). A definitive histological diagnosis was achieved in 31 patients (86.1%), and immunohistochemistry was performed as needed. No adverse events were observed during the procedure, early post-procedure period, or late post-procedure period in any patient (Table 2). In cases in which EUS-TA was performed for SELs > 20 mm, the success rates of pathological differentiation, immunohistochemistry, and definitive histological diagnosis were 100%, 94.7% (18/19), and 95.8%, respectively.
Table 2.
Clinical outcomes of EUS-TA
| Clinical outcomes | EUS-TA with HEP 1p1a | EUS-TA with HEP non-1p1a (n=18) | p-value (1p1a vs. non-1p1a) | |||
|---|---|---|---|---|---|---|
| All patients (n=36) | Patients with SELs ≥20 mm (n=24) | Patients with SELs <20 mm (n=12) | p-value (≥20 vs. <20 mm) | |||
| Technical success | 36 (100.0) | 24 (100.0) | 12 (100.0) | NA | 18 (100.0) | NA |
| Success of pathological differentiation between benign and malignant | 34 (94.4) | 24 (100.0) | 10 (83.3) | 0.11 | 16 (88.9) | 0.59 |
| Success of immunohistochemistrya) | 25/28 (89.3) | 18/19 (94.7) | 7/9 (77.8) | 0.23 | 8/10 (80.0) | 0.59 |
| Success of definitive histologic diagnosis | 31 (86.1) | 23 (95.8) | 8 (66.7) | 0.03 | 15 (83.3) | 1 |
| Adverse events | 0 (0) | 0 (0) | 0 (0) | NA | 0 (0) | NA |
Values are presented as number (%) or number/total number (%).
EUS-TA, Endoscopic ultrasound-guided tissue acquisition; HEP, heparinized wet suction; 1p1a, single-pass single-needle actuation; SEL, subepithelial lesion; NA, not applicable.
Immunohistochemistry was planned only when the pathologist deemed it necessary for establishing the definitive histologic diagnosis.
Regarding specimen quality, the mean tissue integrity and cellularity scores were 1.92 and 1.83, respectively (Table 3). The median maximum length of the white sequential specimen was 3,850 μm (1,757.5–5,250). Comparing SELs ≥20 mm with lesions <20 mm, cellularity and the maximum length of the white sequential specimen were significantly better in SELs ≥20 mm. In contrast, no significant differences were observed between the HEP1p1a and HEP non-1p1a groups for any of these parameters.
Table 3.
Quality of specimens obtained via EUS-TA
| Clinical outcomes | EUS-TA with HEP 1p1a | EUS-TA with HEP non-1p1a (n=18) | p-value (1p1a vs. non-1p1a) | |||
|---|---|---|---|---|---|---|
| All patients (n=36) | Patients with SELs ≥20 mm (n=24) | Patients with SELs <20 mm (n=12) | p-value (≥20 vs. <20 mm) | |||
| Tissue integrity score | 1.92±0.37) | 2.0±0 | 1.75±0.62 | 0.054 | 1.83±0.51 | 0.50 |
| Cellularity score | 1.83±0.51 | 1.96±0.20 | 1.58±0.79 | 0.034 | 1.94±0.24 | 0.38 |
| Maximum length of white sequential specimen (μm) | 3,850 (1,757.5–5,250) | 4,000 (2,375–6,250) | 1,845 (1,207.5–3,775) | 0.031 | 2,705 (1,072.5–3,335) | 0.081 |
Values are presented as mean±standard deviation or median (interquartile range).
EUS-TA, Endoscopic ultrasound-guided tissue acquisition; HEP, heparinized wet suction; 1p1a, single-pass single-needle actuation; SEL, subepithelial lesion.
Final pathologies included GIST in 21 patients (58.3%), adenocarcinoma or squamous cell carcinoma in 5 (13.9%), malignant lymphoma in 1 (2.8%), leiomyoma in 3 (8.3%), ectopic pancreas in 2 (5.6%), lipoma in 1 (2.8%), neurofibroma in 1 (2.8%), schwannoma in 1 (2.8%), and benign tumor without a definitive pathological diagnosis in 1 (2.8%) in all patients (Table 3). The final pathologies of patients with SELs >20 mm are presented in Table 4.
Table 4.
Final diagnosis of the patients
| Final diagnosis | EUS-TA with HEP 1p1a | EUS-TA with HEP non-1p1a (n=18) | ||
|---|---|---|---|---|
| All patients (n=36) | Patients with SELs ≥20 mm (n=24) | Patients with SELs <20 mm (n=12) | ||
| GIST | 21 (58.3) | 16 (66.7) | 5 (41.7) | 6 (33.3) |
| Adenocarcinoma | 3 (8.3) | 3 (12.5) | 0 (0) | 2 (11.1) |
| Squamous cell carcinoma | 2 (5.6) | 1 (4.2) | 1 (8.3) | 0 (0) |
| Malignant lymphoma | 1 (2.8) | 1 (4.2) | 0 (0) | 1 (5.6) |
| Benign subepithelial lesion | 9 (25.0) | 2 (8.3) | 7 (58.3) | 9 (50.0) |
| Leiomyoma | 3 (8.3) | 1 (4.2) | 2 (16.7) | 3 (16.7) |
| Ectopic pancreas | 2 (5.6) | 1 (4.2) | 1 (8.3) | 1 (5.6) |
| Lipoma | 1 (2.8) | 0 (0) | 1 (8.3) | 1 (5.6) |
| Neurofibroma | 1 (2.8) | 0 (0) | 1 (8.3) | 0 (0) |
| Schwannoma | 1 (2.8) | 0 (0) | 1 (8.3) | 0 (0) |
| Brunner’s gland hyperplasia | 0 (0) | 0 (0) | 0 (0) | 2 (11.1) |
| Gastric ulcer | 0 (0) | 0 (0) | 0 (0) | 1 (5.6) |
| Benign tumor without a definitive pathological diagnosis | 1 (2.8) | 0 (0) | 1 (8.3) | 1 (5.6) |
Values are presented as number (%).
EUS-TA, Endoscopic ultrasound-guided tissue acquisition; HEP, heparinized wet suction; 1p1a, single-pass single-needle actuation; SEL, subepithelial lesion; GIST, gastrointestinal stromal tumor.
Details of the five cases in which a definitive histologic diagnosis could not be obtained using EUS-TA are summarized in Table 5. In case 1, the SEL was 15 mm in diameter. As EUS-TA did not yield sufficient specimens, additional MIAB was performed, resulting in a definitive histological diagnosis of lipoma. In case 2, the SEL was 15 mm in diameter. EUS-TA failed to obtain sufficient specimens, and no additional examinations were performed because the patient declined to participate. The patient was observed for over 2 years without progression. The lesion was considered a benign SEL, and the patient is still under follow-up. In cases 3 and 4, GIST was suspected based on standard hematoxylin and eosin staining. Due to insufficient specimen volume for immunohistochemistry, surgical resection was performed without additional tissue acquisition, and GIST was pathologically diagnosed based on the postoperative tissue. In case 5, leiomyoma was strongly suspected based on standard hematoxylin and eosin staining; however, the pathologist deemed the specimen insufficient for immunohistochemistry. The lesion was observed for 5 years without progression. The lesion was considered a leiomyoma, and the patient is still under follow-up.
Table 5.
Details of cases of failure for definitive pathological diagnosis or immunohistochemistry
| Case | Failure of | Age (yr) | Sex | Target organ | Diameter of SELs | Type of needle | Diameter of needle | Session | Additional examination | Final diagnosis |
|---|---|---|---|---|---|---|---|---|---|---|
| 1a) | Differentiation | 48 | Male | Duodenum | 15 | Acquire | 22 | 6 | MIAB | Lipoma |
| 2b) | Differentiation | 83 | Female | Stomach | 15 | TopGain | 19 | 4 | None | Indefinite diagnosis |
| 3c) | Immunohistochemistry | 78 | Female | Stomach | 8 | Acquire | 25 | 3 | None | GIST |
| 4c) | Immunohistochemistry | 74 | Female | Stomach | 25 | TopGain | 22 | 2 | None | GIST |
| 5d) | Immunohistochemistry | 37 | Female | Esophagus | 13 | Acquire | 19 | 6 | None | Leiomyoma |
SEL, subepithelial lesion; MIAB, mucosal incision-assisted biopsy; GIST, gastrointestinal stromal tumor.
In case 1, sufficient specimens were not acquired by endoscopic ultrasound-guided tissue acquisition (EUS-TA); MIAB was alternatively performed.
In case 2, sufficient specimens were not acquired using EUS-TA. Observations were performed for >2 years without progression.
In cases 3 and 4, surgical resection was performed without additional tissue acquisition because GISTs were highly suspected based on standard hematoxylin and eosin staining.
In case 5, leiomyoma was strongly suspected without immunohistochemistry, and observation was performed for 5 years without progression.
DISCUSSION
This study analyzed the efficacy of HEP1p1a in the treatment of upper gastrointestinal SELs using clinical outcomes from our institution. The findings demonstrated a pathological differentiation rate of 94.4% without adverse events among the 36 patients included. However, in five patients, a definitive histological diagnosis using EUS-TA could not be reached.
A detailed review of cases in which a definitive diagnosis was not made revealed that adequate specimens may be difficult to obtain when the lesions are small (<20 mm in diameter) or benign, or when EUS-TA is technically difficult to perform (Table 5). Particularly, in the subgroup analysis limited to SELs >20 mm, the success rate of definitive histologic diagnosis was significantly higher than that of smaller SELs. Furthermore, the quality of the specimens was better for those >20 mm (Table 3). The two guidelines did not recommend EUS-TA for small SELs (<20 mm in diameter).5,7 However, GISTs were diagnosed in five patients with SELs <20 mm in the present study. These findings do not support the approach of managing all SELs <20 mm with observation alone without performing EUS-TA.
In case 1 in the present study, EUS-TA failed to obtain adequate specimens because of the small size of the lesions. However, the addition of MIAB during the procedure enabled the collection of specimens suitable for immunohistochemistry (Fig. 2). MIAB is a useful alternative for tissue acquisition when a sufficient number of specimens cannot be obtained by EUS-TA. In the present study, the transition to MIAB was not mandated when adequate specimens could not be obtained with EUS-TA. Therefore, MIAB was not performed in cases 2–5 in which a definitive histological diagnosis was not achieved. However, a definitive histological diagnosis could have been made if the MIAB had been performed. In the future, clarification of the differences in specimen quality between EUS-TA using HEP1p1a and MIAB, including the appropriate selection criteria for each technique, is required.
Furthermore, not only tumor size but also the organ of the lesion, needle type, and needle diameter might also contribute to the success of obtaining a definitive histological diagnosis; however, these factors could not be discussed in the present study because of the small number of failure cases.
A distinctive feature of this study is the use of a single-pass single-needle actuation method. The utility of EUS-TA with single-pass single-needle actuation was first reported by Nieto et al.,23 who documented the effectiveness of the single-pass single-needle actuation technique in liver biopsies. Following this report, our institution adopted the single-pass single-needle actuation method for EUS-LB; this method was found to be satisfactory for obtaining adequate specimens; therefore, it has also been implemented for SELs. Although Ching-Companioni et al. reported in 2021 that the single-pass three-needle actuation method could yield a more adequate specimen volume using EUS-LB than the single-pass single-needle actuation method, we continued to perform EUS-TA using the single-pass single-needle actuation method due to satisfactory specimen collection with this method.24 Nevertheless, this study’s examination of the single-pass single-needle actuation method for EUS-TA of SELs identified several cases in which the specimen was inadequate, or immunohistochemistry could not be performed. These findings suggest that it is necessary to determine appropriate criteria for determining the number of actuations in a single pass. In this study, the clinical outcomes and specimen quality were compared between EUS-TA performed using HEP 1p1a and HEP non-1p1a techniques as an exploratory analysis. No significant differences were observed in the diagnostic performance or specimen quality. However, because the choice of 1p1a versus non-1p1a was not randomized and was made at the physician’s discretion, a direct comparison is challenging; these findings suggest that the non-inferiority of the 1p1a technique can be reasonably expected.
In this study, EUS-TA was performed using a priming puncture needle with heparinized saline. Several studies have reported the wet heparin suction technique, which involves priming with heparinized saline. A 2014 study compared heparin-primed and non-primed needles using EUS-FNA for pancreatic diseases but found no improvement in specimen quality.25 This lack of benefit may be attributed to factors such as the absence of suction use, the small number of cases studied, the use of 25-gauge FNA needles, and reliance on cytological diagnosis. In 2018, Mok et al. reported that wet heparin resulted in more adequate specimens than dry heparin or dry controls during EUS-LB.26 Subsequently, the usefulness of wet heparin has been repeatedly demonstrated in randomized controlled trials by comparing it with slow-pull and dry suction techniques for various lesions.27-30 These findings suggest that wet heparin might be beneficial for tissue diagnosis using EUS-TA. Xu et al. stated that EUS-TA with heparinized saline priming yielded better specimens because it prevented blood coagulation within the needle from obstructing the entry of the tumor tissue, thereby allowing the acquisition of a greater quantity of higher-quality tumor specimens.30 Furthermore, this facilitated the assessment of whether the expelled specimen contained adequate whitish tissue (Supplementary Video 1, Fig. 1). Even in facilities where ROSE can be performed, the determination of whether adequate volumes of specimens have been collected often depends on MOSE.20 Determining whether sufficient whitish tissue has been collected from large clots or aggregated specimens is challenging. Additionally, the single-pass single-needle actuation method reduces tissue trauma and decreases blood contamination from multiple actuations, indicating its utility in achieving adequate specimen volumes without unnecessary repeated sessions. Notably, the tissue integrity scores in this study were high.
Although the sample size was limited, none of the 54 patients who underwent EUS-TA HEP1p1a or EUS-TA HEP non-1p1a in this study experienced adverse events. A recent meta-analysis reported an adverse event rate of 3.2% using EUS-TA for SELs.31 Although a direct comparison is not possible, these findings suggest that EUS-TA HEP might be safely performed.
This study had certain limitations. Not all the patients during the study period received HEP1p1a. Additionally, this was a single-center, retrospective study involving a relatively small number of patients with variability in needle gauges and types. Although the present study has limitations, EUS-TA with HEP1p1a was performed for SELs of various sizes at multiple sites in the upper gastrointestinal tract and demonstrated favorable diagnostic performance and safety. Therefore, to acquire high-quality specimens while minimizing blood contamination, EUS-TA for SELs using HEP1p1a may be an effective approach. Nevertheless, this is the first report of EUS-TA using HEP1p1a for SELs, which may constitute a valuable and novel contribution to the methodology of EUS-TA for SELs. Future prospective studies are warranted to clarify the optimal case selection for EUS-TA with HEP1p1a and to compare its specimen quality with that of MIAB.
Footnotes
Conflicts of Interest
The authors have no potential conflicts of interest.
Funding
None.
Acknowledgments
We would like to express our sincere gratitude to all the medical staff at Tane General Hospital who were involved in this study.
Author Contributions
Conceptualization: KoT; Data curation: KoT, KM; Formal analysis: TS, KK; Investigation: AK, SH; Methodology: KaT, YS; Project administration: YS, TH, KH; Resources: SO, YK; Supervision: SA, EN, EA, YHi; Validation: YHa, YHi; Visualization: KoT; Writing–original draft: KoT; Writing–review & editing: all authors.
Supplementary Material
Tissue acquisition using heparinized wet heparin and the single-pass single-needle actuation method. The needle stylet was removed, and the needle was primed with heparinized saline before puncture. A single-pass single-needle actuation method was employed. Following a single deep puncture of the subepithelial lesions, 10 mL of negative pressure was applied while withdrawing the needle from the surface. The needle was withdrawn without applying negative pressure. The success of the procedure was assessed by macroscopic on-site evaluation.
A video related to this article can be found online at https://doi.org/ce.2025.354.
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Associated Data
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Supplementary Materials
Tissue acquisition using heparinized wet heparin and the single-pass single-needle actuation method. The needle stylet was removed, and the needle was primed with heparinized saline before puncture. A single-pass single-needle actuation method was employed. Following a single deep puncture of the subepithelial lesions, 10 mL of negative pressure was applied while withdrawing the needle from the surface. The needle was withdrawn without applying negative pressure. The success of the procedure was assessed by macroscopic on-site evaluation.