Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is a standard procedure for obtaining tissue from lesions near the gastrointestinal lumen. However, there is a scarcity of information on the diagnostic performance of EUS-FNA for abdominal lymphadenopathy of unknown causes. To assess the accuracy of EUS-FNA in diagnosing abdominal lymphadenopathy of unknown etiology.
The EUS records of patients with undiagnosed abdominal lymphadenopathy between 2010 and 2015 were reviewed.
A total of 42 patients were included in this study. Adequate specimens were obtained from 40 patients (95%). The final diagnoses were metastatic cancer (
EUS-FNA showed high diagnostic performance for abdominal lymphadenopathy of unknown causes, especially malignancy, lymphoma, and tuberculosis. Therefore, it is a crucial diagnostic tool for this patient population.
Abdominal lymphadenopathy of unknown etiology can be seen in asymptomatic individuals or patients with weight loss, low-grade fever, and abdominal pain [
Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) offers a means to obtain tissue for the diagnosis of lesions adjacent to the gastrointestinal tract, providing adequate specimen for diagnosis in >90% of cases [
The Siriraj Institutional Review Board approved the research protocol, which conformed to the ethical guidelines of the 1975 Helsinki Declaration (Si 465/2011). The EUS database at a tertiary care center from 2010 to 2015 was retrospectively reviewed. Patients with abdominal lymphadenopathy of unknown etiology who underwent EUS-FNA were identified. The inclusion criteria were as follows: (1) enlarged abdominal lymph nodes detected with MRI or abdominal CT in the absence of an identifiable primary lesion and (2) lymph nodes that can be accessed for EUS-FNA based on abdominal imaging. The exclusion criteria were as follows: (1) superficial lymphadenopathy, (2) known history of malignancy, (3) known history of tuberculosis, (4) definite diagnosis determined using modalities other than EUS-FNA, (5) coagulopathy (international normalized ratio >1.5), and (6) thrombocytopenia (platelet count <50,000 µL).
All EUS procedures were performed with a linear echoendoscope (GF-UC140P-AL5; Olympus Optical Co. Ltd., Tokyo, Japan), with the patient under sedation with propofol, by an experienced endosonographer who had performed >2,000 EUS procedures. Aspiration was performed using a 22-gauge FNA needle (EZ shot; Olympus Medical, Tokyo, Japan and EchoTip; Cook Medical, IN, USA). The enlarged lymph nodes were assessed under three scanning scope positions, as follows: (1) gastric station, to assess the celiac, peripancreatic (body and tail), and periportal nodes; (2) duodenal bulb station, to evaluate the peripancreatic (head) and periportal nodes; and (3) second part of the duodenum, to examine lymph nodes near the uncinate process, mesenteric vessels, and inferior vena cava. Needle puncture was performed through the stomach for position (1) and through the duodenum for positions (2) and (3). The technique involved localizing the target lymph node, Doppler assessment of intervening vessels, needle puncture, tissue aspiration, and specimen collection and processing. Under ultrasound guidance, the lymph node was punctured after the Doppler evaluation confirmed the lack of intervening vessels. The stylet was removed, and negative pressure was applied with 5 mL of suction, followed by moving the needle to and fro within the lymph node using the fanning technique. The aspirated material was expelled onto glass slides for visual inspection, and the specimen from each pass was prepared for cytology and cell block assessment. If inadequate macroscopic material was observed, repeated passes were performed (up to four passes). Rapid on-site evaluation was not performed.
The specimens from each pass were divided for cytology and cell block preparation. The aspirated specimens were expelled on a glass slide, smeared for cytologic assessment, and immediately fixed with 95% ethyl alcohol solution. The alcohol-fixed slides were stained with Papanicolaou stain for cytologic examination. The remaining material was placed in a bottle containing formalin solution and embedded in paraffin for cell block assessment. The slides were stained with hematoxylin and eosin and reviewed for histologic features. Additional staining, tissue cultures, and immunohistochemical (IHC) studies were performed when necessary.
The demographics, clinical presentations, laboratory results, radiologic findings, EUS findings, cytopathologic results, and clinical course of the study participants were collected. Information on lymph node characteristics on EUS examination, such as size, shape, echogenicity, border, and location, was obtained. The number of needle passes was recorded. The definite diagnosis was determined on the basis of the cytologic or histologic results of EUS-FNA specimens, clinical course, laboratory findings, and results of radiologic follow-up for at least 12 months.
The final diagnosis was determined on the basis of the (1) histologic findings of either the surgical specimen or cell blocks, (2) cytologic findings, (3) IHC staining of cell blocks, and (4) clinical course and imaging findings during a minimum follow-up of 12 months. A diagnosis of malignancy was made using the following criteria: (1) surgical histology results suggesting malignancy, (2) cytologic or histologic evidence of malignancy based on EUS-FNA specimens, or (3) cytopathologic results suspicious for malignancy combined with the clinical course and follow-up imaging indicating malignancy. Lymphoma was diagnosed on the basis of histologic findings and IHC staining. The diagnosis of tuberculosis was made on the basis of histologic findings of caseating granuloma or positive acid-fast bacilli (AFB) staining of the cell blocks. The diagnosis of other benign conditions required negative cytopathologic assessment and at least 12 months of clinical and imaging follow-up demonstrating no progression or resolution of the enlarged lymph nodes.
The data were analyzed using the Statistical Product and Service Solution (SPSS) statistics software (version 16; SPSS Inc., Chicago, IL, USA). Descriptive statistics were used for demographic, clinical, and laboratory data. Continuous variables were summarized as mean±standard deviation, and categorical variables were summarized as percentages. Qualitative variables were summarized as counts and percentages. Comparisons between groups were performed using the
A total of 803 patients were identified from the EUS database, with 370 patients undergoing EUS-FNA for intra-abdominal solid mass lesions, during the study period. Of them, 328 patients were excluded because of having solid pancreatic masses, pancreatic cystic lesions, subepithelial lesions, periampullary masses, liver masses, and mediastinal masses. Forty-two patients underwent EUS-FNA for isolated abdominal lymphadenopathy of unknown etiology and fulfilled the eligibility criteria. The baseline characteristics of the patients are shown in
Adequate tissue specimens were obtained from 40 patients (95%), all of whom received a definite diagnosis. The final diagnoses included metastatic cancer (
The number, location, size, shape, border, and echogenicity of lymph nodes were evaluated. Three patients (7%) had six nodes. Thirty-five patients (83%) had to two to five nodes, and four patients (9.5%) had a single node. The most common locations of the targeted lymph nodes included the peripancreatic (57%), celiac (38%), and aortocaval regions. (24%). The mean size of the lymph nodes was 24.6±13.2 mm (range 5-70 mm) in the long axis. Of the visualized lymph nodes, 31 were >20 mm, 15 were 16-20 mm, 14 were 11-15 mm, and 7 were <10 mm in size.
The lymph node shape was described as round, oval, or irregular. With respect to the distribution of the lymph node shape, 24 (42%) were round, 14 (25%) were oval, and 18 (32%) were irregular. The lymph node border was reported as regular or irregular. Twenty-three nodes (53.5%) had regular borders, whereas 20 (46.5%) had irregular borders. The echogenic pattern was described as hypoechoic, hyperechoic, or isoechoic Thirty-six lymph nodes (83.7%) were hypoechogenic, six (13.9%) were hyperechoic, and one (2.3%) was isoechoic.
Logistic regression analysis was performed to assess the association between endosonographic features and diagnoses. Univariate analysis indicated that an oval or irregular shape was strongly associated with tuberculosis or inflammatory changes rather than malignancy (OR, 6.0; 95% CI, 1.08 to 33.3;
Furthermore, we evaluated the correlation between EUS and CT in evaluating the shape of the lymph nodes. We found a 48% correlation between the two modalities, with irregular shape being the most concordant interpretation.
EUS-FNA showed a respectable overall diagnostic performance for undiagnosed abdominal lymphadenopathy, with an AUROC, sensitivity, specificity, PPV, and NPV of 0.85, 86.7%, 83.3%, 96.3%, and 55.6%, respectively, as shown in
EUS-FNA is a widely accepted method for tissue acquisition in patients with unexplained abdominal lymphadenopathy. This method provides a high diagnostic accuracy of >90%, without significant complications [
The differences in the distribution of the etiologies of abdominal lymphadenopathy of unknown causes are attributed to the dissimilarity in patient characteristics and geographical variations in disease prevalence. Dhir et al. [
In the past, endosonographic features were proposed to help differentiate benign from malignant lymph nodes. However, later studies demonstrated the limitations of endosonographic features, and the addition of FNA offered higher diagnostic yield [
The success rate of EUS-FNA for adequate sampling was 95% in our study, consistent with previous studies [
The sensitivity slightly decreased for tuberculosis but the specificity and PPV remained excellent. Nonetheless, AFB staining and tissue culture of the aspirates were positive for tuberculosis in patients with a negative cytology, and proper treatment was provided. Furthermore, visualization of pus in the aspirates was indicative of tuberculosis in our cohort. Therefore, purulent specimens should be promptly prepared for AFB staining in this clinical context. The consistency of high diagnostic accuracy and specificity of EUS-FNA (AUROC 0.98, specificity 98%) for intra-abdominal lymphadenopathy has been highlighted in a recent meta-analysis including 10 studies with variations in patient demographics and disease prevalence [
The main strengths of this study are that our study population was highly homogeneous and long-term follow-up data were available in all cases. However, some limitations of our study need to be addressed. First, the clinical and EUS features associated with the final diagnoses were derived from only univariate analysis because of sample size limitations in multivariate analysis. Second, surgical pathology was not available in all cases. Lastly, populations with differing prevalence of diseases may limit the generalizability of our results with respect to post-test probabilities; however, the sensitivity and specificity of the tests do not vary across populations.
In summary, EUS-FNA showed high diagnostic performance for abdominal lymphadenopathy of unknown causes. It offered cytopathologic analysis and IHC evaluation for the diagnosis of metastatic cancer, lymphoma, and tuberculosis. Therefore, it is a crucial diagnostic tool for this challenging clinical dilemma.
None.
Conceptualization: Nonthalee Pausawasdi
Data curation: Tassanee Sriprayoon
Formal analysis: NP, TS, Phunchai Charatcharoenwitthaya
Investigation: NP
Methodology: NP
Project administration: NP
Supervision: NP
Validation: NP
Visualization: NP
Writing-original draft: NP, Kotchakon Maipang
Writing-review & editing: NP, KM, PC
We thank Professor Sanya Sukpanichnant, Department of Pathology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand, for reviewing the pathologic slides and providing insightful suggestions on cytologic and pathologic assessments for lymphoma diagnosis.
Final diagnoses of the study cohort.
The association between endosonographic features and the diagnosis. (A) The bar graph demonstrates the association between the oval or irregular shape of lymph nodes and the diagnosis of tuberculosis or reactive changes compared to malignancy. (B) An endoscopic ultrasound image shows an irregular lymph node. (C) The bar graph demonstrates the association between the peri-hepatic lymph nodes and the diagnosis of tuberculosis. (D) An endoscopic ultrasound image shows enlarged lymph nodes located in the hilar region. (E) The bar graph shows the association between lymph nodes with regular borders and the diagnosis of lymphoma. (F) Endoscopic ultrasound image of a lymph node with a well-defined border. LAD, lymphadenopathy; LN, lymph node.
Characteristic of specimens obtained from a patient with tuberculosis. (A) An endoscopic ultrasound image of a group of peri-hilar lymph nodes in a patient with tuberculosis. (B) Pus in the specimen obtained from fine needle aspiration of a lymph node.
Baseline Characteristics of the Study Cohort
Parameters | Value |
---|---|
Age (years) | 52.7±15.8 |
Sex | |
Male | 25 (60) |
Female | 17 (40) |
Clinical presentation | |
Abdominal pain | 24 (57) |
Weight loss | 11 (26) |
Fever | 7 (17) |
Asymptomatic | 5 (12) |
Anemia | 4 (10) |
Jaundice | 3 (7) |
Abdominal mass | 2 (5) |
Data are presented as mean±standard deviation or number (%).
Diagnostic Performance of Endoscopic Ultrasound-Guided Fine-Needle Aspiration in the Evaluation of Abdominal Lymphadenopathy
Definite diagnosis of intra-abdominal LAD | AUROC | Sensitivity (95% CI) | Specificity (95% CI) | PPV (95% CI) | NPV (95% CI) |
---|---|---|---|---|---|
Overall | 0.850 | 86.7 (70.3-94.7) | 83.3 (43.6-97.0) | 96.3 (81.7-99.3) | 55.6 (26.7-81.1) |
Lymphoma | 1.000 | 100 (67.6-100) | 100 (87.9-100) | 100 (67.6-100) | 100 (87.9-100) |
Non-hematologic malignancy | 0.901 | 84.6 (57.8-95.7) | 95.7 (79.0-99.2) | 91.7 (64.6-98.5) | 91.7 (74.2-97.7) |
Tuberculosis | 0.875 | 75.0 (40.9-92.9) | 100 (87.9-100) | 100 (61.0-100) | 93.3 (78.7-98.2) |
AUROC, area under the receiver operating characteristics; CI, confidence interval; LAD, lymphadenopathy; NPV, negative predictive value; PPV, positive predictive value.