A Basic Approach to Lymph Node and Flow Cytometry Fine-Needle Cytology

Morphology and multiparameter flow cytometry combined for integrated lymphoma diagnosis on small volume samples: possibilities and limitations

The diagnosis of lymphoma relies mainly on clinical examination and laboratory explorations. Among the latter, morphological and immunohistochemical analysis of a tissue biopsy are the cornerstones for proper identification and classification of the disease. In lymphoma with blood and/or bone marrow involvement, multiparameter flow cytometry is useful. This technique can also be applied to fresh cells released from a biopsy sample. For full comprehension of lymphomas, surgical biopsies are best and indeed recommended by the hematopathological community. Currently, however, there is a global trend towards less invasive procedures, resulting in smaller samples such as core needle biopsies or fine needle aspirations which can make the diagnosis quite challenging. In this review, the possibilities and limitations to make an accurate lymphoma diagnosis on such small volume material are presented. After recalling the major steps of lymphoma diagnosis, the respective value of histology, cytology, and flow cytometry is discussed, including handling of small specimens. The benefits of an integrated approach are then evoked, followed by discussion about which attitude to adopt in different contexts. Perhaps contrary to the prevailing view among many pathologists, a full diagnosis on small volume material, combined with relevant ancillary techniques, is often possible and indeed supported by recent literature. A glimpse at future evolutions, notably the merit of artificial intelligence tools, is finally provided. All in all, this document aims at providing pathologists with an overview of diagnostic possibilities in lymphoma patients when confronted with small volume material such as core needle biopsies or fine needle aspirations.

The Diagnostic Value of Fine-Needle Aspiration Cytology in Cervical Lymphadenopathy in Correlation to Postoperative Histopathological Results in a Tertiary Care Center in Saudi Arabia

Background Lymphadenopathy is a frequently encountered presentation in the clinical practice. Cervical lymphadenopathy implies that the cervical nodal tissue measures more than 1 cm in diameter. It requires prompt and accurate diagnosis to begin an appropriate treatment plan. Fine-needle aspiration cytology (FNAC) is considered an initial diagnostic method due to its simplicity, minimal invasiveness, quick availability of results, and low risk of complications. This study aimed to evaluate the diagnostic value of FNAC by comparing the cytological and histological diagnoses of patients with cervical lymph node enlargement at Aseer Central Hospital, Southern Region, Saudi Arabia. Methodology This observational, retrospective, record review study was conducted at the Otorhinolaryngology Head and Neck Surgery Department in Aseer Central Hospital, Abha, Saudi Arabia. Using a data collection sheet, the data of 102 patients were collected from electronic records and reviewed retrospectively. The study included patients who underwent cervical lymph node excision biopsy between 2020 and 2023 due to enlargement of the cervical lymph node. The cytological diagnoses were compared with the histopathological diagnoses of the same enlarged cervical lymph nodes. Results The most common FNAC findings were lymphomas and reactive lymph nodes (26.2% and 19.7%, respectively). The positive predictive value of FNAC was 100% and the negative predictive value was 86.7%. Overall, the diagnostic accuracy was 95.3%. Conclusions FNAC is a safe diagnostic method with minimal invasiveness and complications. This study showed that FNAC and tru-cut biopsy have good diagnostic value in examining patients with cervical lymphadenopathy regardless of their limitations and drawbacks. They have good sensitivity, specificity, positive and negative predictive values, and accuracy.

Comparison of Fine-Needle Biopsy (FNB) versus Fine-Needle Aspiration (FNA) Combined with Flow Cytometry in the Diagnosis of Deep-Seated Lymphoma

Evidence comparing ultrasound endoscopy-guided fine-needle biopsy (EUS-FNB) with EUS-guided fine-needle aspiration (EUS-FNA) in deep-seated lymphoma tissue sampling is insufficient. This study aims to evaluate the diagnostic efficacy of immunohistochemistry (IHC) or flow cytometry (FCM) on specimens obtained from EUS-FNB and EUS-FNA in the diagnosis and staging of deep-seated lymphomas. This real-world, dual-center study prospectively evaluated all eligible specimens from patients who underwent EUS-FNB/FNA over an 8-year period. 53 patients were enrolled, with 23 patients in the EUS-FNB group and 30 patients in the EUS-FNA group. FNB yielded specimens with longer core tissues (0.80 mm [0.55, 1.00] vs. 0.45 mm [0.30, 0.50], p = 0.009) and higher scores of specimen adequacy [4 (3.75, 4.00) vs. 3 (1.00, 4.00), p = 0.025]. Overall analysis revealed that the diagnostic accuracy of IHC based on specimens acquired from EUS-FNB was significantly higher than that of EUS-FNA (91.30% vs. 60.00%, p = 0.013). After controlling confounding factors including lesion size and endoscopists, EUS-FNB with IHC maintained a higher-level diagnostic accuracy compared to EUS-FNA (OR = 1.292 [1.037-1.609], p = 0.023). When FCM was additionally used to analyze the specimen acquired from EUS-FNA, the diagnostic yield was significantly improved (ROC AUC: 0.733 vs. 0.550, p = 0.015), and the AUC of FNB alone or combined with FCM was 0.739 and 0.761. Conclusions: FNB needles generate higher histopathological diagnostic accuracy and specimen quality than FNA for the deep-seated lymphoma. Though the application of FCM significantly improves the diagnostic efficacy of EUS-FNA, FNB was still the preferred diagnostic modality with a shorter procedure time, comparable diagnostic accuracy, and better cost-effectiveness.

Incorporation of ultrasound-guided core biopsy with flow cytometry to assist the diagnosis of cervical lymphoma

PURPOSE

The main purpose of surgery for cervical lymphoma is only for tissue sampling. To establish a patient-friendly diagnostic approach, we investigated the feasibility of ultrasound-guided core biopsy with flow cytometry in the patients with suspected cervical lymphoma.

METHODS

We prospectively recruited patients with suspected cervical lymphoma from Nov 2017 till Jan 2021 in a referral medical center and performed retrospective interpretation of the prospectively acquired data. Ultrasound-guided core biopsy as the tissue sampling approach for the targeted lesions was performed in all patients. The ultrasound-guided core biopsy samples were analyzed by immunohistochemical stains and flow cytometry. The sample quality and the rate of definite and decisive diagnosis obtained by ultrasound-guided core biopsy alone and ultrasound-guided core biopsy with flow cytometry were evaluated.

RESULTS

Total 81 consecutive patients were recruited for analysis. All ultrasound-guided core biopsy samples were qualified for analysis of pathology and flow cytometry. Pathologically, the diagnoses were definite and compatible with their flow cytometry results in 70 patients (86.42%). Either newly-diagnosed or recurrent cervical lymphoma/lymphoproliferative disorders with histologic transformation could be diagnosed by ultrasound-guided core biopsy with flow cytometry. Nine of the 11 patients with pathologically indefinite diagnosis became clinically decisive when flow cytometry was incorporated into the process, which improved the rate of decisive diagnosis to 98.77% (Odds ratio [95% CI]: 6.21 [1.28, 58.96]).

CONCLUSION

Ultrasound-guided core biopsy combined with flow cytometry is suggested to serve as the first-line and patient-friendly diagnostic approach for the patients with suspected cervical lymphoma.

The use of diagnostic patterns for interventional cytopathology during rapid on-site evaluation and final classification

Pathologist-performed fine-needle aspiration, or interventional cytopathology, is a minimally invasive, highly accurate technique for sampling and diagnosing palpable lesions. Utilizing cytomorphologic patterns during rapid onsite evaluation (ROSE) and final classification is one of many strategies that an interventional cytopathologist can employ to simplify the diagnostic approach. Herein, we provide an overview of the salient cytomorphologic patterns encountered in common specimens obtained by the interventional cytopathologist, including major salivary glands, the thyroid gland, and superficial lymph nodes. The topics covered should provide a primer for those interested in utilizing a site-specific, pattern-based approach to cytopathologic evaluation. In summary, cytomorphologic patterns can be used during ROSE to establish adequacy, build a differential diagnosis, and to appropriately triage the specimen for additional investigation, such as microbiology cultures, a liquid-based preparation, a cell block preparation, flow cytometry, chemical analysis, or molecular diagnostic tests. Finally, this approach can be applied at the time of diagnosis to suggest additional ancillary studies, such as immunohistochemistry, and to inform accurate and definitive classification.

Flowcytometry in Reactive Lymph Node Aspirates: Evaluation of Distribution of Populations with Immunophenotypic Outliers

BACKGROUND

Diagnostic accuracy of FNAC for lymphomas has markedly improved when used in conjunction with flowcytometry, especially to differentiate reactive lymph node aspirates from low-grade lymphomas, which is a challenge for cytopathologists. Lymphoma diagnosis by FCM depends on detection of immunophenotypic B and T cell outliers, which are also present in benign lymph nodes, albeit on a subset of cells. These can mimic heterogenous population obtained from lymphomas partially involving a lymph node.

METHODS

In the present study, flowcytometry of FNA/ scrape material from 30 cases of benign lymph nodes was evaluated to study the distribution of lymphoid populations and assess presence and percentages of immunophenotypic outliers.

RESULTS

Majority of lymph nodes sampled were cervical nodes with all cases showing a T cell predominance. CD5/CD19 coexpression was seen in 23.94 ± 9.51% of B cell events in 20 cases and CD10/CD19 coexpression was seen in 3.2% - 20.2% B cell events in 8 cases. None of the above cases showed a light chain restriction. Loss of CD7 (2-28.4% T cell events) and CD5 (12.7% of T cell events) expression was seen in 17 cases and one case respectively.

CONCLUSION

We concluded that immunophenotypic outliers suggestive of lymphomas could be seen in non-lymphomatous lymph node aspirates in a subset of population. However, they could be defined as benign due to absence of light chain restriction and normal CD4: CD8 ratio in all but one case in the present study. This case was confirmed to be benign after clinical correlation and excisional biopsy. Thus, multiparameter FCM along with clinicoradiological correlation can prevent overdiagnosis of lymphomas.

Yield of flow cytometry in addition to cytology for lymph node sampling in patients with incidental axillary adenopathy without a concurrent diagnosis of primary breast malignancy

PURPOSE

Non-specific lymphadenopathy is increasingly being reported especially given the COVID-19 vaccination campaign and is a diagnostic dilemma especially in oncology patients. The purpose of this study was to evaluate the diagnostic accuracy and discordance rate between fine-needle aspiration (FNA) cytology and flow cytometry (FC) immunophenotyping in axillary FNA in patients with morphologically abnormal axillary lymph nodes on imaging and no concurrent diagnosis of primary breast malignancy.

METHODS

This retrospective study included 222 patients who underwent screening or diagnostic axillary ultrasound that yielded suspicious lymphadenopathy without concurrent or recent prior diagnosis of breast cancer and who had subsequent image-guided axillary FNA and FC. Diagnostic accuracy, sensitivity, specificity, and positive and negative predictive value (PPV and NPV) were reported for FNA with cytology alone, and FC alone, and in combination. Discordance rate between FNA cytology and FC was assessed. Discordant cases were evaluated with histology or clinical and imaging follow-up.

RESULTS

Diagnostic sensitivity, specificity, PPV, NPV, and diagnostic accuracy were 88%, 92%, 77%, 96%, and 91%, for FNA alone, 98%, 98%, 92%, 99%, and 98% for FC alone, and 100%, 92%, 79%, 100%, and 94% when combined. The overall discordance rate between FNA and FC was 7% (16/222). 7/16 (44%) patients with discordant results were diagnosed with lymphoma, while 9/16 (56%) patients with discordant results had benign findings.

CONCLUSION

With a diagnostic accuracy of 91%, FNA with cytology is sufficient to screen patients with indeterminate and incidental lymphadenopathy. Flow cytometry could be initially deferred in patients with low pretest probability of lymphoma.

Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration (EBUS-TBNA): Technical Updates and Pathological Yield

Since the endobronchial ultrasound bronchoscope was introduced to clinical practice, endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has become the procedure of choice to sample hilar and mediastinal adenopathy. Multiple studies have been conducted in the last two decades to look at the different technical aspects of the procedure and their effects on the final cytopathological yield. In addition, newer modes of ultrasound scanning and newer tools with the potential to optimize the selection and sampling of the target lymph node have been introduced. These have the potential to reduce the number of passes, reduce the procedure time, and increase the diagnostic yield, especially in rare tumors and benign diseases. Herein, we review the latest updates related to the technical aspects of EBUS-TBNA and their effects on the final cytopathological yield in malignant and benign diseases.

A Pilot Study to Determine the Utility of Automated Tissue Dissociator for Flowcytometry Based Evaluation of Hematolymphoid Tumor Tissue Biopsies

Routine diagnostic biopsy tissue processing, conventional histology/immunohistochemistry (IHC) method is a multi-step and time consuming practice. With the advanced tissue dissociation protocols and panel designing, flow cytometric immunophenotyping (FCI) can be performed on diagnostic hematolymphoid tissue samples using single cell suspensions that economize steps and the time taken. Diagnostic tissue samples from lymph node, mediastinal mass, testicular biopsies and similar sites were dissociated using gentle MACS Octo-dissociator and FCI was performed thereafter. Oral tissue biopsy samples were also processed as a validation set for the protocol. 21 prospective tissue biopsy samples with suspected involvement by a known hematolymphoid neoplasm were processed and evaluated. These included B lymphoblastic lymphoma (n = 12), T lymphoblastic lymphomas (n = 3), Burkitts lymphoma (n = 3) and one case each of granulocytic sarcoma, Hodgkin lymphoma and granulomatous disease. Tissue FCI and IHC were found concordant with identified profile FCI obtained from blood/bone marrow analyses. FCI can produce a highly sensitive and reliable report, within hours, by processing fresh tumor tissue samples from suspected hematolymphoid malignancies. This method can be considered as an effective adjunct to IHC and can be applicable in routine clinical diagnostics, especially in cases that needs quick diagnosis and immediate clinical treatment.

Ultrasound-Guided Fine-Needle Aspiration of Superficial Lymphadenopathy Performed by Interventional Pathologists: The Applicability of the Sydney System from 2 Years of Experience and 363 Cases

INTRODUCTION

The Sydney system proposal for the study and reporting of lymphadenopathy by fine-needle aspiration (FNA) constitutes one of the first attempts to standardize this procedure. Here, we review its applicability.

MATERIALS AND METHODS

A retrospective study in which all ultrasound-guided FNAs (USFNAs) of superficial lymphadenopathy (palpable or not) performed by interventional pathologists in 2 specialized hospital centers were quantified over 2 years. The procedure was systematized, and the diagnoses were reclassified according to the Sydney system categories.

RESULTS

We analyzed 363 USFNAs of lymphadenopathies. The distribution of cases by categories was as follows: insufficient (n = 13; 3.58%), benign (n = 208; 57.30%), atypia of uncertain significance (n = 7; 1.93%), suspicious (n = 21; 5.79), and malignant (n = 114; 31.40%). The risks of malignancy calculated for categories I, II, III, IV, and V were 27%, 3%, 50%, 100%, and 100%, respectively.

CONCLUSION

The implementation of the Sydney system allows the systematization and standardization of the lymph node FNA methodology, with increased efficacy and efficiency. Assimilating the recommendations enables the qualification of the diagnostic procedure.

Diagnostic value of lymph node fine-needle aspiration cytology

Objectives:

This study aims to assess the diagnostic accuracy of cytology by comparing the results of fine-needle aspiration cytology (FNAC) and histopathologic examination.

Material and Methods:

A 4-year retrospective study design was conducted on FNAC samples from the lymph nodes of patients in our hospital between January 2015 and December 2018. The cytopathological diagnoses were compared with the histopathological results of the same excised lymph nodes. Diagnostic sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy rate were calculated.

Results:

A total of 392 lymph nodes were aspirated during the study period. Cytologic analysis of the lymph nodes revealed the following: Reactive lymphoid hyperplasia, 239 (61%); metastatic, 61 (15.6%); granulomatous lymphadenitis, 24 (6.1%); suspicious, 24 (6.1%); pyogenic abscess, 10 (2.6%); necrosis, 4 (1%); non-Hodgkin lymphoma, 2 (0.5%); and non-diagnostic, 28 (7.1%). Immunohistochemical analysis was performed on 26 (6.6%) cases to the cell block samples. Histopathological correlation was available in 73 (18.7%) cases. The overall diagnostic sensitivity, specificity, PPV, and NPV of FNAC of lymph nodes were 87.9%, 100%, 100%, and 89.7%, respectively. The overall diagnostic accuracy was 94.1%. In case of malignancies, the histopathological correlation was 100%. Of four cases with false negative, three were low-grade non-Hodgkin lymphoma and one was granulocytic sarcoma.

Conclusion:

FNAC of lymph nodes is a safe, easy, cheap, quick diagnostic tool and reduces the need for diagnostic excisional biopsy in many patients. Cytological diagnosis can be supported with immunohistochemical analysis of cell block samples. However, lymphomas, particularly low-grade non-Hodgkin lymphomas, are a diagnostic challenge and additional studies such as flow cytometry are required in cases with suspicious for lymphoma.

A Simple and Practical Guide for Triaging Lymphocyte-rich Effusions for Ancillary Studies

Lymphocyte-rich effusions of the body cavities may represent a reactive/benign condition, primary effusion lymphoma, or systemic lymphoma with secondary malignant effusion, either as initial presentation or as a late complication. Cytomorphologic examination is essential and fundamental for diagnosis and may provide important clues to the nature of diseases. However, based on morphology alone, cytologic diagnosis of lymphocyte-rich effusions could be very challenging, particularly when the lymphocytes are small. Cytologists/cytopathologists might be uncertain when a lymphocyte-rich effusion specimen warrants a comprehensive hematopathologic workup. Herein we present a simple and practical algorithmic approach. On the basis of the cytomorphology of lymphocytes (small vs. large cells), presence or absence of cellular atypia, and clinical information (an earlier history or current lymphoma), the lymphocyte-rich effusion samples could be triaged for ancillary studies including immunophenotyping and molecular assays if indicated. Incorporation of cytomorphology, correlation with clinical information, and appropriate application of various ancillary techniques is mandatory for a correct diagnosis of lymphocyte-rich effusion specimens.

Combined EBUS-IFB and EBUS-TBNA vs EBUS-TBNA alone for intrathoracic adenopathy: A Meta-analysis

BACKGROUND

Endobronchial ultrasound (EBUS) guided intranodal forceps biopsy (IFB) is considered complimentary to EBUS-TBNA for patients with intrathoracic lymphadenopathy when either additional tissue is requested for comprehensive molecular testing, or for suspected lymphoma and sarcoidosis. This is a systematic review and meta-analysis to investigate the diagnostic yield and complications of combined EBUS-IFB and EBUS-TBNA compared to EBUS-TBNA alone.

METHODS

We performed a systematic search of MEDLINE, Embase, and Google Scholar for studies evaluating the use of EBUS-IFB for diagnosis of intrathoracic adenopathy, assessing the quality of each study using the QUADAS-2 tool. Using inverse-variance weighting, we performed a meta-analysis of diagnostic yield estimations. We also reviewed the complications related to the procedure.

RESULTS

Six observational studies with 443 patients undergoing 467 biopsies were included in the final analysis. Meta-analysis yielded a pooled overall diagnostic yield of 67% (312/467) for EBUS-TBNA and 92% (428/467) for EBUS-TBNA + EBUS-IFB, with an inverse variance - weighted OR of 5.87 (95% CI, 3081 to 9.04, p<0.00001) and an I ²of 15%. The overall complications included pnuemomediastinum (1%), bleeding (0.8%) and respiratory failure (0.6%). The funnel plot analysis illustrated no major publication bias. Subgroup analysis showed increased diagnostic yield for lymphoma (86% vs 30%, p=0.03) and sarcoidosis (93% vs 58%, p<0.00001).

CONCLUSIONS

The addition of EBUS-IFB to EBUS-TBNA improves the overall diagnostic yield of sampling intrathoracic adenopathy when compared to EBUS-TBNA alone. The complication rates of the combined approach are higher than with EBUS-TBNA, but are reportedly lower than with transbronchial or surgical biopsies.

Processing and Reporting of Cytology Specimens from Mediastinal Lymph Nodes Collected using Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration: A State-of-the-Art Review

Endobronchial ultrasound (EBUS)-guided transbronchial needle aspiration (TBNA) is presently the preferred modality for sampling mediastinal lymph nodes. There is an unmet need for standardization of processing and reporting of cytology specimens obtained by EBUS-TBNA. The manuscript is a state-of-the-art review on the technical aspects of processing and reporting of EBUS-TBNA specimens. A literature search was conducted using the PubMed database, and the available evidence was discussed among the authors. The evidence suggests that at least one air-dried and one alcohol-fixed slide should be prepared from each lymph node pass. The remaining material should be utilized for microbiological analysis (in saline) and cell block preparation (10% formalin or other solutions). Wherever available, rapid-onsite evaluation should be performed to assess the adequacy of the sample and guide the need for additional material. The lymph node aspirate should also be collected in Roswell Park Memorial Institute solution in cases where lymphoma is under consideration. The use of liquid-based cytology provides good quality specimens that are free from blood and air-drying artifacts and can be used wherever available. Sample adequacy and the diagnostic category should be furnished separately in the cytology report.