Grading follicular lymphoma on fine-needle aspiration specimens-A practical approach

Commentary on small-volume biopsy of follicular lymphoma: Practical issues in the molecular era

Follicular lymphoma (FL) is a common subtype of non-Hodgkin lymphoma derived from germinal center B-cells. Small-volume biopsies (SVBs), including fine-needle aspiration, needle core biopsy, and cell blocks, are often used for the assessment of patients with FL. Recently, Fitzpatrick et al. found that additional biopsies were frequently needed to supplement SVB for the initial diagnosis of FL. However, regardless of the type of SVB used, additional biopsies were usually not necessary for assessments for transformed or recurrent FL. Their multi-institutional study reflects the fact that SVB may be sufficient for clinical decision-making in these medical settings, although surgical excision is the gold standard for a definitive diagnosis of FL. With ancillary tests and advances in molecular testing, SVB has become increasingly popular and helpful, although there are practical limitations.

Small volume biopsy diagnostic yield at initial diagnosis versus recurrence/transformation of follicular lymphoma: A retrospective Cyto-Heme Interinstitutional Collaborative study

BACKGROUND

Few studies have evaluated diagnostic yield of small volume biopsies (SVB) for the diagnosis and management of follicular lymphoma (FL).

METHODS

The authors performed a multi-institutional retrospective analysis of SVBs including fine-needle aspiration (FNA) and needle core biopsy (NCB) for initial FL diagnosis and suspected recurrence or transformation of FL. A total of 676 workups beginning with SVB were assessed for the mean number of biopsies per workup, the proportion of workups requiring multiple biopsies, and the proportion with a complete diagnosis including grade, on initial biopsy.

RESULTS

Compared to workups performed for question transformation/recurrence, those done for initial FL diagnosis were significantly more likely to require multiple biopsies (p < .01), had a higher mean number of biopsies per workup (1.7 vs. 1.1, absolute standardized difference = 1.1), and a lower complete diagnosis rate at initial biopsy (39% vs. 56%). At initial FL diagnosis, NCB +/- FNA was associated with fewer biopsies per workup compared to FNA +/- CB (1.2 vs. 1.9), fewer workups requiring multiple biopsies (23% vs. 83%), and a higher complete diagnosis rate (71% vs. 18%). In contrast, during assessment for transformation/recurrence, NCB and FNA showed a similar mean number of biopsies per workup (1.2 vs. 1.2) and few workups required multiple biopsies (6% vs. 19%).

CONCLUSIONS

SVB at initial FL diagnosis often required additional biopsies to establish a complete diagnosis. In contrast, when assessing for transformed/recurrent FL, additional biopsies were generally not obtained regardless of SVB type, suggesting that in these clinical settings SVB may be sufficient for clinical decision-making.

Diagnostic Discrepancies in Small-volume Biopsy for the Initial Diagnosis, Recurrence, and Transformation of Follicular Lymphoma: A Multi-Institutional Collaborative Study

Small-volume biopsies (SVBs) including fine-needle aspiration (FNA), cell block, and needle core biopsies (NCB) are increasingly utilized to diagnose and guide the clinical management of lymphoma. We established a multi-institutional interdisciplinary collaboration of cytopathologists, hematopathologists, and oncologists focused on the role of SVB in the management of patients with follicular lymphoma (FL). To assess the performance characteristics of SVB in this setting, we evaluated all consecutive SVBs performed for clinical indications of initial diagnosis, recurrence, or transformation of FL over a 5-year period and focused on the 182 that had at least one subsequent biopsy within 3 months as part of the same clinical work-up. The most common outcome of a subsequent biopsy as part of the same clinical work-up was a more specific diagnosis usually assigning the pathologic grade (111/182, 61%), followed by a complete agreement with the SVB (24/182, 13%), and change from nondiagnostic on initial biopsy to diagnostic on subsequent biopsy (21/182, 12%). A minority resulted in a diagnostic change from benign to lymphoma (17/182, 9%), a change in FL grade (5/182, 3%), or change in the lymphoma diagnostic category (4/182, 2%). There were no cases where an initial diagnosis of lymphoma was overturned. The distribution of discrepancies was similar across initial SVB types (FNA, FNA + cell block, NCB with or without FNA). Tissue limitations were noted in a minority of cases (53/182, 29%) and were enriched among initially nondiagnostic biopsies (16/21, 76%). Flow cytometry immunophenotyping was performed in the majority of cases both at the first and last biopsy (147/182, 81%). SVB can be a powerful method to detect FL in various clinical indications, with discrepant cases mostly resulting from a refinement in the initial diagnosis.

Diagnostic accuracy of Thinprep® in cervical lymph node aspiration: Assessment according to the Sydney system

BACKGROUND

Fine-needle aspiration cytology (FNAC) is a reliable technique that has been used for many years in lymphadenopathy diagnosis. Although conventional smear is the standard approach in FNAC, liquid-based cytology (LBC) is accepted as an alternative method. Reporting standardization is a significant gap in fine-needle aspiration cytology, leading to failure in pathologist-clinician dialog and interobserver variability. In 2020, an expert panel proposed the Sydney system for classifying and reporting lymph node aspiration cytology. This study aimed to evaluate the diagnostic accuracy of LBC in lymph node aspiration cytology under the guidance of the Sydney system.

METHODS

Five hundred-four LBC samples were reevaluated and classified according to the Sydney system. Of these, n = 24 were categorized as L1-inadequate/non-diagnostic, n = 283 as L2-benign, n = 36 as L3- atypical cells of undetermined significance/atypical lymphoid cells of uncertain significance (AUS/ALUS), n = 48 as L4-suspicious, and n = 113 as L5-malignant. Four hundred-one samples were histopathologically confirmed. The diagnostic accuracy of LBC and the risk of malignancy for each Sydney category were calculated.

RESULTS

The results were as follows: sensitivity 98.97%; specificity 98.60%; positive predictive value 94.80%; negative predictive value 99.29%; and overall diagnostic accuracy 98.75%. The ROM was 16.6% for L1, 0.7% for L2, 88.8% for L3, and 100% for L4 and L5.

CONCLUSION

LBC is suitable for use in lymph node aspiration under the guidance of the Sydney system and has high diagnostic accuracy. Future comprehensive studies will increase the applicability of the Sydney system and minimize interobserver variability.

Lymph node FNA cytology: Diagnostic performance and clinical implications of proposed diagnostic categories

BACKGROUND

Despite widespread clinical use, lymph node fine-needle aspiration cytology (LN-FNAC) lacks universal acceptance for definitively diagnosing lymphomas. This is likely due to reports of lower diagnostic performance, inconsistent terminology use in cytopathology diagnostic reports, and only limited data on the clinical implications of LN-FNAC diagnoses. Recently, a uniform LN-FNAC cytopathological diagnostic reporting system was proposed (the Sydney System). This study evaluated LN-FNAC diagnostic performance and risks of malignancy associated with the proposed diagnostic categories.

METHODS

LN-FNAC specimens obtained in 2018-2019, with and without concurrent core biopsy, to evaluate for suspected lymphoma were analyzed (n = 349). LN-FNAC diagnoses were compared with final diagnoses obtained via subsequent tissue biopsy and/or clinical assessment.

RESULTS

The mean patient age was 57.6 years, and 41% were female. LN-FNAC was the initial diagnostic test in 223 (63.9%), and it was used to evaluate for recurrence in 126 (36.1%). LN-FNAC diagnosed 202 hematological malignancies (57.9%), 23 nonhematological malignancies (6.6%), and 124 reactive processes (35.5%). Subsequent tissue biopsy was performed in 42 (12%). The risks of malignancy per diagnostic category were as follows: inadequate, 58.3%; benign, 6.4%; atypical, 69.2%; suspicious, 96.7%; and malignant, 99.3%. LN-FNAC demonstrated up to 96.3% sensitivity, 91.91% specificity, and 87.35% accuracy. Optimal specimen quality and the use of intradepartmental consultation reduced diagnostic error rates in FNA cases without concurrent core biopsy (P = .029 and P = .0002 respectively).

CONCLUSIONS

LN-FNAC is accurate and reliable for the diagnosis of lymphoma. Inadequate LN-FNAC samples should be resampled due to a significant associated risk of lymphoma. The diagnostic performance of LN-FNAC may be improved with good specimen quality and reviews by multiple pathologists. Understanding the risks of malignancy associated with LN-FNAC diagnostic categories will help to guide optimal patient management.

Assessment of risk of malignancy by application of the proposed Sydney system for classification and reporting lymph node cytopathology

BACKGROUND

Fine-needle aspiration cytology (FNAC) is one of the most commonly used techniques for evaluating lymphadenopathy. Recently, the Sydney system was proposed for assessing the performance, classification, and reporting of lymph node (LN) cytopathology. The present study was conducted to assess the risk of malignancy associated with each of the diagnostic categories of the proposed Sydney system.

METHODS

This was a 2-year retrospective study of LN-FNAs; cytologic diagnoses were categorized by the proposed Sydney system. Cytological diagnoses were correlated with the corresponding histopathological diagnoses to assess diagnostic accuracy and risk of malignancy for each diagnostic category.

RESULTS

Of 23,335 FNAs during the study period, 6983 (30%) were performed on LNs. Of these, 289 (4.1%) cases were reported as nondiagnostic/inadequate (L1); 3397 (48.6%) were reported as benign (L2); 33(0.5%) as atypical cells of undetermined significance (L3), 96 (1.4%) as suspicious for malignancy (L4) and 3168 (45.4%) as malignant (L5). Subsequent histopathology was available for 618 (8.8%) cases. On cytohistopathologic correlation, 552 (89.3%) were concordant and 66 (10.7%) discordant. The overall sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy of LN-FNA were 79.9%, 98.7%, 98.4%, 83.1%, and 89.3%, respectively. The risk of malignancy was 27.5% for the nondiagnostic category, 11.5% for the benign, 66.7% for the atypical, 88% for the suspicious, and 99.6% for the malignant categories.

CONCLUSIONS

FNAC has high diagnostic accuracy for the diagnosis of various LN pathologies. Application of the proposed Sydney system can help in achieving uniformity and reproducibility in cytologic diagnoses and also help in risk-stratification on cytology.

Flow cytometric analysis of fine needle aspirates is affected by tumor subtype, but not by anatomic location nor technique

BACKGROUND

Current clinical practices are shifting towards utilizing less invasive biopsy techniques, including fine needle aspiration (FNA) and needle core biopsies. If a patient has a suspected hematologic malignancy, a portion of the FNA sample is typically submitted for flow cytometry (FC) analysis, providing valuable immunophenotypic data.

METHODS

FNA specimens were identified via a pathology database search. All cases were morphologic evaluated and a subset of cases were analyzed by FC.

RESULTS

245 hematologic FNA specimens were identified; 84% of these cases had an adequate number of cells for FC analysis, and an unequivocal morphologic diagnosis (benign or malignant) was rendered in 85%. The percentage of cases with an unequivocal diagnosis was statistically significantly higher in those with associated FC than with those without FC (90% vs 58%). Neither FNA technique nor anatomic site affected the likelihood of obtaining an adequate sample for FC analysis and/or rendering a definitive morphologic or unequivocal FC diagnosis. Likewise, tumor subtype did not affect the likelihood of acquiring enough cells for FC analysis, but occasionally resulted in equivocal FC diagnoses or discordant FNA and FC diagnoses. Aggressive B-cell lymphomas and Hodgkin lymphomas were significantly less likely to be detected by FC as compared to low-grade B-cell lymphomas. Discrepancies between FNA and FC diagnoses occurred in 13% of cases. The majority of discrepancies (78%) included FC false negatives, while only 22% of cases had atypical or positive FC with negative FNA.

CONCLUSIONS

FNA with associated FC is a powerful diagnostic technique; however, lymphoma subtype may affect diagnostic sensitivity by FC, and therefore, discordant FNA and FC results should be interpreted with caution.

Diagnosis of Lymphoma Using Fine-Needle Aspiration Biopsy and Core-Needle Biopsy: A Single-Institution Experience

OBJECTIVE

The objective is to study the efficacy of fine-needle aspiration biopsy (FNAB) and core-needle biopsy (CNB) in the diagnosis of lymphoma in a single institution.

STUDY DESIGN

We retrospectively reviewed 635 FNAB/CNB cases performed in our institution to rule out lymphoma during a 4-year period and collected the relevant clinical and pathological information for statistical analysis.

RESULTS AND CONCLUSIONS

This cohort comprised 275 males and 360 females, with a median age of 57 years. Among the 593 cases with adequate diagnostic materials for lymphoma work-up, 226 were positive for lymphoma, 286 were negative for lymphoma, and 81 were nondiagnostic. Each case had an FNAB, and 191 cases also underwent a CNB. The subclassification rate according to the WHO (2008) was 67% overall, 81% for the FNAB with CNB group, and 40% for the FNAB group. In the FNAB with CNB group, the subclassification rates for cases with and without a history of lymphoma were not significantly different. A definitive diagnosis of lymphoma relied on ancillary studies, but was not affected by location, or the needle gauge of CNB. Follow-up data revealed a high diagnostic accuracy of FNAB with CNB. In conclusion, the use of FNAB and CNB with ancillary studies is effective in providing a definitive diagnosis of lymphoma in our experience at the Northwell Health System.

Sensitivity of fine-needle aspiration biopsy for diagnosing and grading follicular lymphomas using a multiparameter approach in a cancer center

OBJECTIVES

The diagnosis and grading of follicular lymphomas (FLs) by fine-needle aspiration biopsy (FNAB) has not been systematically compared with core needle biopsy (CNB). We evaluated the sensitivity of FNAB in diagnosing and grading FLs using a multiparameter approach in a large cancer center.

METHODS

We retrospectively identified CNBs of lymph nodes diagnosed as FL that also had a concurrently acquired FNAB on the same site. The majority of cases had flow cytometric analysis and these results were available for interpretation of both the FNAB and CNB.

RESULTS

Out of 342 patients, CNB diagnoses included 291 (85%) low-grade (LG) FLs, 30 (9%) high-grade (HG) FLs, and 21 (6%) non-graded FLs/other. FNAB diagnoses included 194 (57%) LG FLs, 19 (6%) HG FLs, 93 (27%) non-graded FLs, 9 (3%) large B-cell lymphomas (LBCL) of follicle center origin, and 27 (7%) insufficient for diagnosis/other. Review of non-graded FLs showed 45% LG, 35% indeterminate due to polymorphous lymphoid cells with increased numbers of large cells, and 20% scant cellularity. Sensitivity of FNAB for diagnosing FL was 89%, and 66% for LG FL. The latter increased (94%), however, when grading was performed.

CONCLUSION

FNAB is highly sensitive for diagnosing FLs when cellular material for cytomorphology and flow cytometric analysis is obtained, and grading is feasible for most LG FLs. A subset of FLs composed of a polymorphous lymphoid population with increased numbers of large cells may be more difficult to grade, and HG FLs can be difficult to distinguish from CD10-positive diffuse LBCLs.

Endoscopic/Endobronchial Ultrasound-Guided Fine Needle Aspiration and Ancillary Techniques, Particularly Flow Cytometry, in Diagnosing Deep-Seated Lymphomas

Evaluation of deep-seated lymphomas by fine-needle aspiration (FNA) can be challenging due to their reduced accessibility. Controversy remains as to whether FNA and ancillary techniques can be used to diagnose deep-seated lymphomas reliably and sufficiently for clinical management. Most published studies are favorable that endobronchial ultrasound (EBUS)/endoscopic ultrasound (EUS)-FNA plays an important role in the diagnosis of deep-seated lymphomas. The addition of ancillary techniques, particularly flow cytometry, increases diagnostic yield. While subclassification is possible in a reasonable proportion of cases, the reported rates of successful subclassification are lower than those for lymphoma detection/diagnosis. The diagnostic limitation exists for Hodgkin's lymphoma, grading of follicular lymphoma, and some T-cell lymphomas. The role of FNA in deep-seated lymphomas is much better established for recurrent than primary disease. It remains unclear whether the use of large-sized-needle FNA or a combination of core needle biopsy and FNA improves subclassification. It is important for cytopathologists to have considerable understanding of the WHO lymphoma classification and develop a collaborative working relationship with hematopathologists and oncologists. As EUS/EBUS-FNA techniques advance and sophisticated molecular techniques such as next- generation sequencing become possible, the role of FNA in the diagnosis of deep-seated lymphomas will possibly increase.

Branched-chain in situ hybridization for κ and λ light chains: A powerful ancillary technique for determining B-cell clonality in cytology samples

BACKGROUND

Current immunohistochemical and in situ hybridization (ISH) assays are generally inconclusive for clonality unless plasmacytic differentiation is present. This study examined a series of cytology specimens and explored the ability of a branched-chain RNA (bRNA) ISH assay for immunoglobulin κ constant (IGKC) and immunoglobulin λ constant (IGLC) to detect a clonal population of B lymphocytes.

METHODS

Pathology databases were used to identify fine-needle aspiration biopsies (n = 28) and exfoliative cytology samples (n = 20). Demographic, flow cytometry, and excision biopsy results were recorded. bRNA ISH was performed on the Leica Bond platform with the following probes: IGKC, IGLC, immunoglobulin λ-like polypeptide 5 (IGLL5), and a housekeeping gene (HKG).

RESULTS

The bRNA ISH assay was validated with 30 surgical biopsies. On bRNA ISH, a clonal B-cell population (light-chain ratio > 10:1) was detected in 22 of 28 cases with a final diagnosis of lymphoma. In 2 cases, a κ predominance was present, although the ratio was <10:1. Eleven of the 17 κ-clonal lymphomas also expressed IGLL5, the latter recognized by the presence of an intranuclear signal. Two B-cell lymphomas lacked IGKC and IGLC, whereas 2 cases were negative for the HKG. In 12 of the 20 cases with reactive lymphoid tissue, bRNA ISH identified a polyclonal lymphoid population. No light-chain messenger RNA was detected in 6 cases (typically those associated with very few B cells).

CONCLUSIONS

The automated bRNA ISH platform is a robust technique for detecting a clonal B-cell population in cytology material.

Cytopathology in the diagnosis of lymphoma

FNA is a simple, safe, and an inexpensive sampling technique that plays an important role in the evaluation of lymphadenopathy. The key to enhancing the accuracy of FNA diagnosis of lymphoma is the multi parameter approach in which the cytomorphologic features are evaluated in correlation with the results of ancillary studies and clinical context. A full understanding of the current lymphoma classification, clinical features associated with each lymphoma subtype and the impact of the diagnosis on patient management is essential in FNA diagnosis of lymphoma. It is also important to recognize the limitations of FNA in the primary diagnosis of some subtypes of lymphoma, and tissue biopsy should be recommended for a definitive diagnosis and subclassification in such cases.

Tissue flow cytometry immunophenotyping in the diagnosis and classification of non-Hodgkin's lymphomas: a retrospective evaluation of 1,792 cases

A retrospective analysis of 1,792 solid tissues suggestive of lymphoma, submitted over a 12-year period, was carried out and flow cytometry (FC) results were compared with histologic findings. The final histologic diagnosis of cases documented in this report is as follows: 1,270 non-Hodgkin's lymphomas (NHL); 17 composite lymphomas; four NHL plus carcinomas; five post-transplant lymphoproliferative disorders; 105 Hodgkin's lymphomas (HL); eight acute leukemias; 42 tissue cancers; and 341 non-neoplastic diseases. A strong correlation between morphology and FC data was observed among hematological malignancies (1,268/1,304, 97.2%) with the exception of HL. Among B-NHL, FC detection of clonally restricted B-cell allowed the identification of lymphomas that were not histologically clear and the differential diagnosis between follicular lymphoma and reactive hyperplasia. A high correlation level (r = 0.83; P < 0.0001) was obtained in comparing proliferation results obtained by FC and immunohistochemistry. Among T-NHL, FC detection of an aberrant phenotype direct histologic diagnosis in cases having less than 20% of neoplastic cells. In nine cases, FC suggested the need to evaluate a neoplastic population, not morphologically evident. Results show that FC routinely performed on tissue samples suspected of lymphomas is a fundamental adjunct to morphology in the diagnosis of NHL and may enhance the performance of the histologic evaluation so as to achieve the final diagnosis. To the best of our knowledge, this is the first report in the literature of a wide series of tissues also studied by FC.

[Role of cytology in hematopathological diagnostics]

The role of cytology has so far been underrecognized in the diagnostic process of hematopathological questions. This article presents an algorithm which allows a stepwise work-up of cytology specimens obtained by minimally invasive ultrasound-guided fine needle aspiration in patients with unexplained lymph node swelling. Moreover, it is shown how the selective separation of cytology specimens allows the application of immunophenotypic analysis including flow cytometry and immunohistochemistry as well as molecular analyses, such as fluorescence in situ hybridization (FISH) and polymerase chain reaction (PCR) strategies. With the integrative procedure presented, cytology offers an excellent cost-effective tool for the diagnostic approach of patients with suspected hematopathological malignancies allowing a high diagnostic accuracy, ideal for initial diagnosis or follow-up.

The utilization of fine needle aspiration biopsy (FNAB) and flow cytometry (FC) in the diagnosis and classification of non-Hodgkin B-cell and T-cell lymphomas

The subtypes of non-Hodgkin lymphomas may have similar morphology, but have a wide variation in origin, immunophenotype and biological features. Many ancillary investigations are available to help overcome these problems, including fine needle aspiration biopsy (FNAB) and flow cytometry (FC). FNAB coupled with FC can reliably distinguish between reactive and neoplastic lymphoid populations. It can be used in the diagnosis and classification of many lymphomas, obviating the need for surgical biopsy in a significant number of patients.

The utility of endobronchial ultrasound-guided transbronchial needle aspiration biopsy in the diagnosis of mediastinal lymphoproliferative disorders

BACKGROUND

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) biopsy is routinely used to stage lung cancer; however, its usefulness in diagnosing lymphoproliferative disorders has not been well established. In this retrospective study, we determined the utility of EBUS-TBNA in evaluating mediastinal lymphadenopathy in patients with suspected lymphoproliferative disorders.

METHODS

The authors searched the pathology database at their institution to identify all patients who had undergone EBUS-TBNA biopsy for possible lymphoproliferative disorders. The cytologic diagnoses were correlated with concurrent and subsequent biopsy findings and clinical follow-up data.

RESULTS

Of 886 lymph nodes evaluated by EBUS-TBNA biopsy, 91 nodes from 33 patients (23 men and 10 women) were eligible. Fourteen patients had a history of lymphoma. Adequate material for diagnosis was obtained in 31 of 34 procedures (1 patient had 2 procedures). The cytologic diagnoses of the 31 adequate procedures included 19 with benign disease (8 reactive lymph nodes and 11 granulomatous inflammation), 8 with lymphoma (2 large B-cell, 2 small lymphocytic, 2 Hodgkin, 1 mantle cell, and 1 T-cell lymphoblastic), 2 with cells suspicious for Hodgkin lymphoma, and 2 cases with atypical cells.

CONCLUSIONS

EBUS-TBNA proved to be useful for evaluating mediastinal lymphadenopathy in patients with suspected lymphoproliferative disorders. Its use may decrease the need for invasive diagnostic procedures. Immediate assessment is valuable in these cases because of the need to triage material for immunophenotyping or other studies to determine optimal and clinically meaningful diagnoses.

Diagnosis of deep-seated lymphomas by endoscopic ultrasound-guided fine needle aspiration combined with flow cytometry

OBJECTIVE

Although endoscopic ultrasound combined with fine needle aspiration (EUS-FNA) is rapidly becoming the preferred diagnostic approach for the sampling and diagnosis of gastrointestinal and mediastinal malignancies, there are limited data as to its use in the diagnosis of lymphoproliferative disorders. Therefore, we carried out a retrospective evaluation of the performance of EUS-guided FNA combined with flow cytometry (FC) as a tool to improve overall sensitivity and specificity in the diagnosis of lymphoma.

METHODS

Of 1560 patients having EUS-guided FNA during the period of the study, a total of 56 patients were evaluated by cytology with FC after EUS-FNA. There was adequate material to perform FC analysis for all but one case.

RESULTS

EUS-FNA-FC gave a diagnosis of lymphoma in 11 cases and of reactive lymphadenopathy in 20. A specific histological type was defined by FC alone in eight cases. The remaining cases were diagnosed later by cytology and cell block sections: 13 carcinomas, nine granulomatous lymphadenopathies and one mediastinal extramedullary haematopoiesis. One case was considered only suspicious for lymphoma on cytology and FC but was not confirmed on molecular analysis and one had insufficient material for FC.

CONCLUSIONS

Our results show that a combination of EUS-FNA-FC is a feasible and highly accurate method, which may be used for the diagnosis and subtyping of deep-seated lymphoma, providing a significant improvement to cytomorphology alone both for diagnosis and treatment planning, as long as immunocytochemistry is available for non-lymphoma cases.

Classifying B-cell non-Hodgkin lymphoma by using MIB-1 proliferative index in fine-needle aspirates

BACKGROUND

MIB-1 proliferation index (PI) has proven helpful for diagnosis and prognosis in non-Hodgkin lymphomas (NHLs). However, validated cutoff values for use in fine-needle aspiration (FNA) samples are not available. We investigated MIB-1 immunocytochemistry as an ancillary technique for stratifying NHL and attempted to establish PI cutpoints in cytologic samples.

METHODS

B-cell NHL FNA cases with available cytospins (CS) MIB-1 immunocytochemistry results were included. Demographic, molecular, immunophenotyping and MIB-1 PI data were collected from cytologic reports. Cases were subtyped according to the current World Health Organization classification and separated into indolent, aggressive, and highly aggressive groups. Statistical analysis was performed with pairwise Wilcoxon rank sum test and linear discriminant analysis to suggest appropriate PI cutpoints.

RESULTS

Ninety-one NHL cases were subdivided in 56 (61.5%) indolent, 30 (33%) aggressive, and 5 (5.5%) highly aggressive lymphomas. The 3 groups had significantly different MIB-1 PIs from each other. Cutpoints were established for separating indolent (<38%), aggressive (> or =38% to < or =80.1%) and highly aggressive (>80.1%). The groups were adequately predicted in 76 cases (83.5%) using the cutpoints and 15 cases showed discrepant PIs.

CONCLUSIONS

MIB-1 immunohistochemistry on CS can help to stratify B-cell NHL and showed a significant increase in PI with tumor aggressiveness. Six misclassified cases had PIs close to the cutpoints. Discrepant MIB-1 PIs were related to dilution of positive cells by non-neoplastic lymphocytes and to the overlapping continuum of features between diffuse large B-cell lymphoma and Burkitt lymphoma. Validation of our approach in an unrelated, prospective dataset is required.

Immunocytochemical typing of primary tumors on fine-needle aspiration cytologies of lymph nodes

The aim of this study was to analyze the role of immunocytochemistry as an ancillary method on routine FNACs of enlarged lymph nodes, using different markers. In a validating cohort study all patients had confirmatory histological and/or clinical follow-up. 10 FNACs were analyzed for the differentiation of Non-Hodgkin Lymphoma (NHL) from metastatic carcinoma (MC), 30 cases to identify the sites of metastatic unknown primary tumors and 16 cases were checked to confirm clinical suspicion of a specific MC. Accuracy to differentiate NHL from MC was 100%, 92.3% to identify a primary tumor site of MC, and 100% to confirm a clinical suspicion of a specific MC. In 7 cases, the site of the primary tumor remained clinically unknown. Application of immunocytochemical markers on the same slide used for microscopic diagnosis is a useful tool in the routine assessment of FNACs of lymph nodes.

Recent advances in protein profiling of tissues and tissue fluids

Creating protein profiles of tissues and tissue fluids, which contain secreted proteins and peptides released from various cells, is critical for biomarker discovery as well as drug and vaccine target selection. It is extremely difficult to obtain pure samples from tissues or tissue fluids, however, and identification of complex protein mixtures is still a challenge for mass spectrometry analysis. Here, we summarize recent advances in techniques for extracting proteins from tissues for mass spectrometry profiling and imaging. We also introduce a novel technique using a capillary ultrafiltration (CUF) probe to enable in vivo collection of proteins from the tissue microenvironment. The CUF probe technique is compared with existing sampling techniques, including perfusion, saline wash, fine-needle aspiration and microdialysis. In this review, we also highlight quantitative mass spectrometric proteomic approaches with, and without, stable-isotope labels. Advances in quantitative proteomics will significantly improve protein profiling of tissue and tissue fluid samples collected by CUF probes.