A retrospective study on the comparative use of fine-needle biopsy and aspiration for the diagnosis and classification of malignant lymphoma in Japan

Article information

Clin Endosc. 2025;.ce.2024.320

Publication date (electronic) : 2025 May 27

doi : https://doi.org/10.5946/ce.2024.320

Fumitaka Niiya^,1, Akihiro Nakamura², Yasuo Ueda², Takafumi Ogawa², Naoki Tamai¹, Masataka Yamawaki¹, Jun Noda¹, Tetsushi Azami¹, Yuichi Takano¹, Masatsugu Nagahama¹

¹Division of Gastroenterology, Department of Internal Medicine, Showa University Fujigaoka Hospital, Yokohama, Japan

²Division of Pathology, Showa University Fujigaoka Hospital, Yokohama, Japan

Correspondence: Fumitaka Niiya Division of Gastroenterology, Department of Internal Medicine, Showa University Fujigaoka Hospital, 1-30 Fujigaoka, Aoba-ku, Yokohama, Kanagawa 227-8501, Japan E-mail: f.niiya@med.showa-u.ac.jp

Received 2024 November 28; Revised 2025 February 2; Accepted 2025 February 9.

Abstract

Graphical abstract

INTRODUCTION

Malignant lymphoma (ML) originates from the lymphoid cells and can be fatal. Recently, treatment for ML has witnessed significant progress, with several potent chemotherapeutic agents being developed.1 Therefore, when ML is suspected, early pathological diagnosis is essential, and treatment should be promptly initiated.

Pathological diagnosis is crucial. In addition, obtaining large tissue samples for pathological evaluation, including immunohistochemistry, is necessary to diagnose lymphadenopathies. Endoscopic ultrasound-guided tissue acquisition (EUS-TA) has been widely used to diagnose gastrointestinal lesions and those in surrounding areas.2 Despite EUS-TA being the preferred sampling method, fine-needle aspiration (FNA) needles, which are effective for obtaining cytological specimens, are less efficient at acquiring core tissues necessary for histological evaluation.

Many studies, including randomized controlled trials and meta-analyses, have compared the diagnostic efficacy of fine-needle biopsy (FNB) and FNA needles, yielding conflicting results.3-10 The debate over whether FNB provides better diagnostic performance than FNA remains unresolved. Therefore, the diagnostic capabilities must be examined separately for each tumor type because of the differences in pathological conditions. Recent studies comparing FNB and FNA needles in cases of neuroendocrine tumors or autoimmune pancreatitis have highlighted the benefits of FNB, particularly in core tissue acquisition and diagnostic yield.11-14 However, comparative studies between FNB and FNA focusing on ML are scarce, primarily because of the rarity of the condition. Therefore, this study aimed to compare the diagnostic accuracy of FNB and FNA in ML.

METHODS

Pathological assessment

Pathological and tissue scoring assessments were performed retrospectively by two experienced pathologists (Y.U. and T.O.). The obtained specimens were extruded onto a plate using a stylet or Hank’s solution. Histological and cytological analyses were conducted on the solid components after formalin fixation and solution components after dissolution in Hank’s solution, respectively. Immunohistochemistry was attempted on all specimens; however, it was not performed on samples with insufficient material. For immunohistochemical staining, L26 (CD20) and CD79a were used as markers of the B-cell lineage, whereas CD3 and CD5 were used as T-cell lineage markers. Additionally, CD4, CD8, CD10, CD30, CD56, B-cell lymphoma-2, B-cell lymphoma-6, multiple myeloma oncogene-1, cyclin D1, and Ki-67 were included as appropriate. The final diagnosis of ML was established based on pathological findings and the clinical course in accordance with the World Health Organization (WHO)16 criteria. For cases that could not be subclassified using EUS-TA, we performed additional procedures such as repeat EUS-TA, percutaneous lymph node biopsy, or bone marrow biopsy whenever feasible. A benign diagnosis was confirmed if no lymphadenopathy progression was observed on follow-up imaging for more than 6 months.

The quantity of tissue was evaluated using the scoring system outlined by Gerke et al.17 Cellularity was scored on a scale from 0 to 5, where 0 indicated samples with insufficient material for interpretation; 1 represented samples allowing limited cytological interpretation; 2 denoted sufficient material for adequate cytological interpretation; 3 indicated samples allowing limited histological assessment; 4 signified sufficient material for adequate histological interpretation (total material within a 10-power field in length) (Fig. 1A); and 5 indicated samples sufficient for adequate histological interpretation (total material exceeding a 10-power field in length) (Fig. 1B).

Fig. 1.

Histological evaluation of sampling tissue (hematoxylin and eosin stain, ×10). (A) A score of 4 indicates sufficient material for adequate histological interpretation (total material within a 10-power field in length). (B) A score of 5 indicates samples sufficient for adequate histological interpretation (total material exceeding a 10-power field in length).

RESULTS

Patients

We enrolled 56 patients with suspected ML, who underwent EUS-TA between July 2016 and April 2024. Of these, 23 were excluded because of other diseases: sarcoidosis (n=2), splenic hematoma (n=1), paraganglioma (n=1), sclerosing angiomatoid nodular transformation (n=1), nonspecificity (n=12), and metastasis (n=6). Following exclusion, 33 patients diagnosed with ML were included in the study: 14 patients in the FNB group and 19 patients in the FNA group (Fig. 2).

Fig. 2.

Flow chart of the study design. EUS-TA, endoscopic ultrasound-guided tissue acquisition; FNB, fine-needle biopsy; FNA, fine-needle aspiration.

Table 1 presents patient characteristics. No significant differences in age or sex ratio were observed between the two groups. The target lesions were predominantly in the abdominal lymph nodes (85.7% on FNB vs. 84.2% on FNA), without significant differences in the incidence of masses in the spleen and adrenal glands (p=0.1). The lesion size was significantly larger in the FNB group than in the FNA group (median, 45 mm vs. 20 mm; p<0.01). The puncture route also differed significantly between the groups (p=0.02), with a lower frequency of transgastric approaches (50% vs. 89.5%) in the FNB group than in the FNA group. Additionally, the number of passes was similar between the two groups (p=0.46). Needle size distribution also varied significantly (p=0.017), with the FNB group predominantly using 22-G needles and the FNA group using more 19-G and 25-G needles. Regarding the final diagnoses according to the WHO subclassification, in the FNB group, 7.1% of patients were diagnosed with mixed cellularity classical Hodgkin lymphoma, 28.6% with diffuse large B-cell lymphoma, 35.7% with follicular lymphoma, 7.1% with plasma cell myeloma, 7.1% with unclassified B-cell lymphoma, and 7.1% with high-grade B-cell lymphoma, with MYC, BCL2, and BCL6 rearrangements, and 7.1% with unclassified T-cell lymphomas. In the FNA group, 5.3% of patients were diagnosed with classical Hodgkin lymphoma, 5.3% with mixed cellularity classical Hodgkin lymphoma, 26.3% with diffuse large B-cell lymphoma, 42.1% with follicular lymphoma, 5.3% with nodal marginal zone lymphoma, and 15.8% with unclassified B-cell lymphoma. No significant difference in the distribution of the final diagnoses was found between the FNB and FNA groups (p=1).

Table 1.

Characteristics of patients with malignant lymphoma and final classification of malignant lymphoma (including cases confirmed by additional biopsy)

Outcomes of EUS-TA

Table 2 summarizes the EUS-TA outcomes in terms of diagnostic accuracy, WHO subclassification diagnostic rate, specimen quality, and AEs. The diagnostic accuracies of cytology were 78.6% and 63.2% in the FNB and FNA groups, respectively, with no significant differences between the groups (p=0.46). Regarding histology, the diagnostic accuracies were 100% and 78.9% in the FNB and FNA groups, respectively, with no significant intergroup differences (p=0.12). The diagnostic rate for WHO subclassification was significantly higher in the FNB group (71.4%) than in the FNA group (31.6%) (p=0.037). In the EUS-FNB group, the ML subclassification could not be determined in four cases. Of these, three patients underwent additional percutaneous lymph node biopsies, and one patient proceeded directly to chemotherapy without further biopsy. In the EUS-FNA group, ML subclassification was not achieved in 13 cases. Among these, eight patients underwent additional percutaneous lymph node biopsies, two underwent bone marrow biopsies (one case was unsuccessful in ML subclassification), one underwent EUS-TA, and two patients underwent chemotherapy without additional biopsy. Regarding specimen quality, in the FNB group, 7.1%, 21.4%, and 71.4% of the samples were scored as 3 (samples allowing limited histological assessment), 4 (sufficient material for adequate histological interpretation within a 10-power field), and 5 (sufficient material for adequate histological interpretation beyond a 10-power field), respectively. In the FNA group, 15.8%, 42.1%, and 42.1% of the samples scored 3, 4, and 5, respectively, with no significant difference in the overall scores between the two groups (p=0.32). No AEs, such as bleeding or perforation, were reported in either group.

Table 2.

Comparison of diagnostic yield for malignant lymphoma in the FNB and FNA groups

Subgroup analysis of outcomes: 22-G FNB vs. FNA needles

Table 3 presents the results of the subgroup analysis limited to 22-G FNB and FNA needles. The diagnostic accuracies of cytology were 75% and 50% in the FNB (n=12) and FNA (n=8) groups, respectively, with no significant differences between the groups (p=0.36). For histology, the diagnostic accuracies were 100% and 87.5% in the FNB and FNA groups, respectively, with no significant differences between the two groups (p=0.4). The WHO subclassification diagnostic rate was significantly higher in the FNB group (83.3%) than in the FNA group (25%) (p=0.019). Regarding specimen quality, in the FNB group, 100% of samples were scored as ≥4 compared with 75% in the FNA group, with no significant difference between the groups (p=0.15).

Table 3.

Subgroup analysis of malignant lymphoma diagnostic yield in the FNB and FNA groups limited to 22-G

DISCUSSION

This retrospective study compared the diagnostic yields of FNB and FNA needles for ML using immunohistochemistry. Two important clinical observations were made. First, FNB achieved a higher diagnostic rate for ML than FNA, although the difference was not statistically significant. Second, regarding the diagnostic ability of ML classification, the use of FNB needles ensured that sufficient tissue samples were obtained for accurate ML classification. Therefore, FNB is considered a highly effective method for diagnosing ML.

EUS-guided sampling has become the preferred method for the pathological diagnosis of solid pancreatic masses because of its high accuracy (sensitivity and specificity of 85% to 89% and 96% to 99%, respectively).19–21 Recently, FNB needles have become more commonly used in EUS-TA. A meta-analysis comparing FNB and FNA needles demonstrated that FNB provides higher pooled diagnostic accuracy and better tissue core acquisition rate and requires fewer passes for diagnosis in pancreatic and non-pancreatic lesions than FNA.9 However, the effectiveness of FNB for tumors other than pancreatic cancer remains controversial, particularly in the context of ML, where no consensus exists on which needle is more appropriate.

EUS-FNB demonstrated borderline superiority over EUS-FNA in terms of sensitivity for the diagnosis of ML. To evaluate lymph nodes, FNA alone may suffice in many cases22,23; however, diagnosing ML remains challenging, regardless of the needle used. FNB needles are preferred when a histological core is required for specialized staining. Yasuda et al.24 reported a high sensitivity of 95% for diagnosing ML using a 19-G standard needle, attributed to the large sample volume obtained. However, the rigidity of the 19-G needle can make puncture difficult compared with the 22-G needle; in cases where the flexible 19-G needle fails, a 22-G FNA needle has been shown to successfully puncture pancreatic masses.25 Therefore, comparing FNB and FNA, regardless of needle size, is important for diagnosing ML. Previous studies have shown that the sensitivity of EUS-TA for ML was 80% and 60.5% with FNB and FNA, respectively, indicating a favorable trend for FNB.26 In our study, the sensitivity for cytology was 75% and 50% with FNB and FNA, respectively, while that for histological diagnosis was 100% and 78.9% with FNB and FNA, respectively. Although the differences were not statistically significant, FNB yielded better results than FNA, supporting its utility in diagnosing ML, which is consistent with previous findings.

ML classification is crucial for determining appropriate treatment plans. Therefore, combined histomorphological assessment and immunohistological staining are typically employed to accurately subclassify lymphomas. Although only a few reports have assessed the ML classification, Okuno et al.27 reported a diagnostic success rate of ML classification of >90% using 19-G needles. In our study, the diagnostic rate of ML classification was significantly higher in the FNB group (71.4%) than in the FNA group (31.6%). To the best of our knowledge, few previous reports have directly compared FNB and FNA needles for lymphoma subclassification. Yang et al.28 reported that FNB resulted in a more definitive diagnosis of ML than FNA. Our findings confirm that FNB needles are more effective than FNA needles for this purpose. Moreover, we conducted a detailed analysis to compare the number of pathological specimens using a scoring system. The quantity of tissue obtained varies depending on the degree of fibrosis and necrosis, suggesting that different tumor types should be evaluated separately. However, no study has specifically compared the quantity of tissues obtained from patients with ML using a scoring system. Therefore, our study indicates that the FNB needle can retrieve more adequate samples for histological interpretation than the FNA needle, suggesting that it leads to a higher success rate in ML classification.

In this study, we observed that 19-G needles were not used in the FNB group but were used in 31% of cases in the FNA group, leading to a difference in the gauge of the puncture needles employed. FNA needles with a gauge of 19-G reportedly can obtain a sufficient sample volume, with a performance comparable to that of 19-G FNB needles.27 Consequently, we conducted a sub-analysis limited to 22-G needles to compare the performance of FNB and FNA. The results demonstrated that the FNB group had a significantly higher success rate in diagnosing the ML subclassification than the FNA group. Additionally, all samples with a score of ≥4 in the FNB group were 100%, indicating that FNB needles are likely more suitable for obtaining diagnostic samples than FNA needles. However, even with 22-G FNA needles, 75% of samples scored ≥4, indicating a discrepancy with the success rate of ML subclassification diagnosis. One reason for this discrepancy could be that, even within samples with a score of 5, a mix of sample quantities that are more and less suitable for ML subclassification may exist. Kaneko et al.29 proposed a refinement of the traditional score of 5–6 to define samples suitable for next-generation sequencing. This concept may similarly apply to the appropriate sample quantity for ML subclassification in our study. Another reason may be that the critical regions for immunohistochemical staining were sparse, necrotic, or fragmented. The scoring system we used primarily assessed cellular quantity rather than the preservation of tissue architecture. Consequently, despite showing adequate cellularity, EUS-FNA samples often lack the intact structure required for detailed immunohistochemical evaluation. In contrast, EUS-FNB yields core tissue with better architectural preservation, enabling a more accurate ML subclassification. Additionally, certain subtypes may require more extensive immunophenotyping or molecular analyses, which were not feasible with the obtained tissue. The retrospective nature of this study may have introduced variability in the processing or staining.

No AEs were observed in either group, and no cases of bleeding or perforation were noted. EUS-FNB can be regarded as safe as EUS-FNA in the sampling of lymphadenopathy.30 Furthermore, EUS-TA is considered a safe procedure for diagnosing ML; this also holds when using FNB needles.

This study has some limitations. First, some bias was inevitable owing to the retrospective nature and small sample size of the study. Second, the types and gauges of needles used in this study were not standardized. The frequent use of 19-G needles may have influenced these results, particularly in the FNA group. However, 19-G needles are considered to have diagnostic capabilities comparable to those of FNB needles, and if 19-G were not used in the FNA group, the results for the FNA group may have been worse. Indeed, in the subgroup analysis that standardized the needles to 22-G, the FNA group showed lower diagnostic performance than the FNB group. Third, in this study, the FNB group showed significantly larger tumor sizes than the FNA group, which may have influenced the outcomes, despite conducting a secondary analysis focusing on using 22-G needles. Therefore, future studies should increase their sample size and conduct multivariate analyses. Fourth, the scoring of histological specimens was performed without blinding, and flow cytometry and cytogenetic assessments were not conducted in this study because of the limited number of cases. These assessments are crucial for the diagnosis and treatment of ML, and further investigations with a larger number of cases are needed. Nonetheless, to the best of our knowledge, only a few studies have compared the diagnostic accuracy of FNB and FNA for ML, including its subtypes, making the results of this study clinically significant.

In conclusion, FNB demonstrated high diagnostic accuracy and superior ML classification capabilities compared with FNA in evaluating ML. Both needles were safely used in this study. Additionally, the diagnosis of lymphoma may be enhanced by using EUS-FNB instead of EUS-FNA. However, we recognize the necessity for further studies with larger sample sizes, including genetic testing, to validate these findings.

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