Scrape cell-block technique for fine needle aspiration cytology smears

Utility of guided FNAC and cell block preparation from liver and gall bladder masses: Learning experience from a tertiary care center

INTRODUCTION

Ultrasound- and CT-guided fine needle aspiration cytology (FNAC) increases the accessibility of intra-abdominal masses to the liver and gall bladder with the advantages of low cost and high diagnostic yield. Cell block technique has been known for further increasing the diagnostic accuracy.

AIMS AND OBJECTIVES

We aimed to study the effectiveness of FNAC and the cell block method in cytological diagnosis of liver and gall bladder masses. We also followed a step-wise approach to increase the success rate.

MATERIALS AND METHODS

A 2-year observational study was done from July 2020 to June 2022. Total 80 guided (CT and ultrasound) aspirations were done from space occupying/mass lesions in the liver [74 (92.5%)] and gall bladder [6 (7.5%)], out of which cell blocks by the plasma thrombin method were prepared in 12 cases (15%). The on-site radiological details were noted, and rapid on-site evaluation was done in 65 cases (81.25%). The prepared cytology slides were stained with Papanicolaou, H and E and May-Grunwald Giemsa (MGG) stain. The cytological diagnosis was noted, and the uses and limitations (if any) were observed in each case. A step-wise structured questionnaire format was developed to assist the reporting pathologist so as not to miss out on important diagnostic observations, if present.

RESULTS

FNAC in 71 cases (88.7%) gave a conclusive diagnosis. The maximum number of cases were of adenocarcinoma [38 (51.3%)] from the liver followed by hepatocellular carcinoma in 10 cases (13.5%). In gall bladder masses, all 6 cases (100%) were positive for malignancy, out of which 4 cases (66.7%) could be characterized as adenocarcinoma. The cell block preparation was helpful in reaching the diagnosis as well as typing the malignancy in 10 cases (83.3%). The chief limitation observed on conventional cytology smears was inadequate cellularity, which caused inconclusive diagnosis in 9 cases (11.25%). The reporting questionnaire was helpful chiefly in terms of time-efficient reporting in 34 cases (42.5%), increasing the ease and confidence in 69 cases (86.25%) and the advantage of reproducibility of data in all cases (100%) according to the case-by-case evaluation by the reporting pathologists.

CONCLUSION

Guided FNAC in conjunction with the cell block technique is extremely helpful in the evaluation of mass lesions of the liver and gall bladder for cytological diagnosis. A proper step-wise approach may be useful to reach a quick and effective diagnosis.

Cell blocks in cytology: review of preparation methods, advantages, and limitations

Cell blocks are cytologic preparations that are processed as paraffin embedded blocks in a manner comparable to formalin-fixed paraffin-embedded tissue in surgical pathology. In addition to serving as an adjunct to other cytologic preparations for morphologic diagnosis, cell blocks play an increasingly important role as they yield tissue sections that can be utilized for ancillary testing such as immunohistochemical stains and molecular studies. While essentially universally viewed as playing a pivotal role in cytopathology practice, there are various factors that limit their use in practice and contribute to dissatisfaction with cell block quality. Cell block preparation, as opposed to tissue processing in surgical pathology, is more variable with many different protocols in use today. This review explores the most commonly used cell block preparation techniques currently in use with review of the unique advantages and limitations each method presents. The goal of this work is to serve as a resource that can aid in making more informed decisions about which cell block protocol may work best for individual laboratories.

Collection and processing of effusion fluids for cytopathologic evaluation

Accumulation of fluid in serous cavities as effusions may have to be drained for therapeutic and diagnostic indications. As compared to many other procedures, the technicality of paracentesis procedures is relatively easy. As a result, effusion fluids comprise a significant proportion of specimens in most of the laboratories, including those in community settings.

Because of relative complexities in the cytopathologic evaluation of effusion fluids, application of appropriately standardized protocol is critical for achieving optimum results by applying standardized steps from handling of specimens during the initial stages of collection to the final interpretation phase. Understanding various limitations and challenges during collection and processing phases by all the personnel involved, including clinicians, pathologists, and technologists is critical for optimum diagnostic yield.

This review highlights various cytopreparatory techniques applicable to effusion cytology in one place. It is organized by projecting the details predominantly in the form of different tables and figures including summary of the recommended protocols with reagents and stains used. Also included is a sample of cytopathology report based on the approach discussed in this series.

Culture Cell Block Controls as a Tool to the Biomolecular Diagnosis of Infectious Diseases

The cell block (CB) technique has allowed easy obtainment of samples such as cellular and culture suspensions, to perform specific molecular tests such as immunohistochemistry and in situ hybridization. It has been improved along time, accuracy, and quality of the diagnoses, however, the cost of a commercial gel matrix for the preparation of CB is high and not suitable depending on the situation. The objective of this study is to test agarose as an alternative to the commercial gel matrix in the preparation of Aspergillus fumigatus' CB.

The Value of Cellblock in Diagnosing Pancreatic Lymphomas

BACKGROUND

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is the diagnostic tool of choice for pancreatic solid mass lesions. Pancreatic lymphomas represent an infrequent and challenging cytologic diagnosis. Our aim was to determine the diagnostic value of cellblock (CB) in the diagnosis of pancreatic lymphomas.

METHODS

We retrieved pancreatic EUS-FNAs performed over 10-years from our institution's database. We correlated the cytologic and CB diagnosis with the histologic diagnosis as a gold standard.

RESULTS

We found 5 cases (2 women and 3 men; age range, 37-66 years [average age, 52 years]) of pancreatic lymphomas with histologic follow-up biopsies. They included 1 case of T-cell lymphoma (TCL), 1 case of plasma cell neoplasm (multiple myeloma [MM]), 1 case of diffuse large B-cell lymphoma (DLBCL), 1 case of classic Hodgkin lymphoma (HL), and 1 case of high-grade B-cell lymphoma (HGBCL). Cytologically, the cases of HL and DLBCL were suspected, the cases of TCL and MM were confused with undifferentiated carcinoma and neuroendocrine carcinoma, and the case of HGBCL was inconclusive. CB samples were of value in highlighting the morphologic details of lymphomas and allowed confirmation, proper classification, and grading of the lymphomas using immunohistochemistry that matched tissue biopsies.

CONCLUSIONS

EUS-FNA smears with CBs are helpful diagnostic tools, differentiating lymphomas from other malignancies and from nonneoplastic lymphocyte-rich lesions. CBs allow proper classification and grading of cases of pancreatic lymphomas.

Immunocytochemistry on scrape cellblock: An aid in the diagnosis of metastatic neoplasm with unknown primary: A series of four cases

Scrape cellblock (SCB) is a novel technique to suggest possible primary site in fine-needle aspiration cytology (FNAC) smears from the liver, lung, and lymph nodes which are the common sites of metastasis of many primary tumors. Immunocytochemistry (ICC) on SCB averts the need of more invasive diagnostic procedures and gives a conclusive diagnosis. We present a series of four cases with unknown primary site, in which ICC was done on SCB to suggest possible primary site. Three of them were liver space-occupying lesions (SOL) and one from the periportal lymph node. In all four cases, wet-fixed smear for hematoxylin and eosin stain was prepared as routine procedure. FNAC was reported as metastatic adenocarcinoma in two and metastatic spindle cell neoplasm in one liver SOL. Periportal node was reported metastatic adenocarcinoma. Two hematoxylin and eosin-stained slides from each case with higher cellularity were used to scrape off the material to prepare SCB. ICC was put which gave conclusive diagnosis in all the cases. On ICC, two cases of metastatic carcinoma in the liver were diagnosed as metastatic neuroendocrine neoplasm from Gastrointestinal Tract and metastatic adenocarcinoma from the stomach. Spindle cell neoplasm of the liver was diagnosed as gastrointestinal stromal tumor from the stomach. Pancreatic head mass in metastatic periportal node was confirmed later by radiologic examination. SCB is a useful technique to make the best use of available material where reaspiration is difficult. ICC on SCB is of maximum utility to suggest possible primary sites in metastatic cases with unknown primary or where biopsy of the lesion is not possible.

Indian Academy of Cytologists Guidelines for Collection, Preparation, Interpretation, and Reporting of Serous Effusion Fluid Samples

Cytological examination plays an important role in the initial work-up of the serous cavity effusion fluids to find out the possible etiology as benign or malignant. Among malignant effusions, cytology is helpful in determining the exact type, site, and stage of the tumor. However, for reporting effusion cytology specimens, there is no consistent and reproducible reporting system.

CellBlockistry: Chemistry and art of cell-block making - A detailed review of various historical options with recent advances

Cell-blocks are paraffin-embedded versions of cytology specimens comparable to the formalin-fixed paraffin-embedded (FFPE) tissue from surgical pathology specimens. They allow various elective ancillary studies on a variety of specimens with enhanced cytopathologic interpretation, including opportunity to perform molecular tests. However, different dictionaries and internet search engines primarily project "cellblock" and "cell block" definition in relation to prisons. Most of the top searches lead to information related to "prison cells" followed by a few cytopathology-related searches. Due to this in the current review, it is recommended that the word for cytopathology purposes should be hyphenated and spelled as "cell-block." Cell-blocks have been increasingly indicated on most cytology specimens. Its role is growing further with the ongoing addition of new immunohistochemistry (IHC) markers with technical advances including multicolor IHC and the SCIP (subtractive coordinate immunoreactivity pattern) approach. In addition, it is an important source of tissue for many ancillary studies even as archived material retrospectively at later stage of management if the cell-blocks are improved qualitatively and quantitatively. Because of this, the significance of cell-block is critical with the increasing number of molecular markers standardized predominantly on FFPE tissue. As compared to core biopsies, high-quality cell-blocks prepared with enhanced methodologies predominantly contain concentrated diagnostic tumor cells required for the molecular tests without significant stromal contamination. This review introduces the terminology of CellBlockistry as the science of studying chemistry and the art of achieving quantitatively and qualitatively improved cell-blocks from different types of specimens. The review addresses the cell-block making process as "cell-blocking" and discusses different historical limitations with emphasis on recent advances.

Manufactured Cell Blocks: Turning Smears into Sections

Whilst cytological smears are still the basis of cytodiagnosis, there is an increasing role for ancillary testing. Specimens obtained are not always optimal, often with limited material for ancillary studies. Several reports have described the utility of scraping material from cytological smears to manufacture cell blocks to provide material for ancillary studies. Our objective was a retrospective review of the PathWest (QE2) experience with manufactured cell blocks (mCB) over the last 10 years. A total of 178 fine-needle aspiration cases with mCB were extracted from the PathWest database. Data were subdivided into: lymph node (89), breast (31), thyroid (23), soft tissue (13), liver (11), and other sites (11) and were analysed. All available material was reviewed. Diagnostic material was identified in 163 mCB (91.6%). Immunohistochemistry (IHC) was performed on 149 cases. Positive IHC staining was seen in 139 cases (93.3%) and advanced the diagnosis in 119 cases (79.9%). Molecular studies were performed on 38 mCB with adequate DNA obtained in 37 cases (97.3%). Our review has demonstrated that cellular material scraped from air-dried or prefixed smears can be made into cell blocks. Antigen preservation is adequate to provide diagnostically useful results with IHC whilst DNA integrity is preserved to allow molecular analysis.

The usefulness of various cytologic specimen preparations for PD-L1 immunostaining in non-small cell lung carcinoma

INTRODUCTION

Evaluation of programmed cell death ligand-1 (PD-L1) on formalin-fixed paraffin-embedded (FFPE) histologic specimens is required for immunotherapy with pembrolizumab in non-small cell lung carcinoma (NSCLC). A significant percent of patients may be diagnosed on cytology samples alone; however, FFPE tissue may not always be available. Here, we evaluated the feasibility of PD-L1 staining on a variety of cytologic preparations including conventional cell blocks (CB), cell-transfer cell blocks (CTCB), and direct smears.

MATERIALS AND METHODS

We identified 30 NSCLC cytology cases that had PD-L1 status evaluated on a concurrent core needle biopsy. Papanicolaou-stained smears (PS) were reviewed and a moderately cellular smear was selected per case to prepare a CTCB. CTCB, CB, and PS (when available) were stained with PD-L1 22C3 and tumor proportion scores (TPS) were compared across all preparations with the concurrent core biopsies.

RESULTS

Concordance of PD-L1 positivity in CB and PS versus core biopsy was high, 80% (12 of 15) and 94.4% (17 of 18), respectively. CTCB versus core biopsy concordance was lower in comparison, 62% (13 of 21) for PD-L1 positivity. Overall, TPS was lower in CTCB compared with CB and PS. Among the 3 preparations, CTCB and CB sections were easier to interpret as PS displayed various artifactual staining patterns.

CONCLUSIONS

In summary, our study demonstrates that CB and PS preparations are suitable surrogates for histologic FFPE tissue for determining PD-L1 status in NSCLC patients. CTCBs, on the other hand, show high discordance and are not optimal specimens. Pre-analytic factors in unconventional cytology preparations may need optimization and negative results should be interpreted with caution.

Cell Block in Cytological Diagnostics: Review of Preparatory Techniques

OBJECTIVE

The cell block (CB) technique refers to the processing of sediments, blood clots, or grossly visible tissue fragments from cytological specimens into paraffin blocks that can be cut and stained by the same methods used for histopathology. The technique brings additional tissue architectural information. CB can be used for ancillary techniques such as immunocytochemistry and molecular techniques.

STUDY DESIGN

We reviewed the literature on the various preparatory techniques of CBs.

RESULTS

There is a wide range of preparatory techniques for CBs and no golden standard for CBs exists: tens of methods are used in various institutions. The majority of the methods are modified in house techniques with a few commercially available kits. The techniques most commonly used are the plasma/thrombin method, the agar method, and commercially available Histogel- and Cellient CB-methods. Dissatisfaction with the cellular yield of the CBs is common.

CONCLUSIONS

In the CBs, the cytological material is preserved for future use, which is a tremendous advantage in the era of targeted therapy and biobanking. The CB is thus central to the future of cytology: more can be done with less material and with less invasiveness to the patient.

Role of cell block in cytopathologic evaluation of image-guided fine needle aspiration cytology

Context:

Fine needle aspiration cytology (FNAC) of superficial or deep-seated lesion is an increasingly common practice, eliminating time consuming and costly diagnostic procedures and providing rapid and safe diagnosis.

Aims:

To assess utility of cell block preparation method in increasing sensitivity of cytodiagnosis in deep-seated image-guided FNACs.

Settings and Design:

This was a hospital-based observational study conducted in the Department of Pathology, over a period of one and a half years.

Materials and Methods:

A total of 46 cases of abdomino-pelvic and intrathoracic masses subjected to guided FNACs were included. Along with conventional smears, cell blocks were prepared by using AAF (95% Ethanol 34 ml + formalin 4 ml + Glacial acetic acid 2 ml) as fixative agent.

Statistical Analysis Used:

Done using MedCalc Version 12.7.5.0 to find out the sensitivity, specificity, and diagnostic accuracy of conventional smears and cell blocks.

Results:

The sensitivity, specificity, and diagnostic accuracy of cell blocks in our study was 71.11%, 100%, and 71.73%, respectively. The figures for FNA smears were 62.22%, 100%, and 63.04%, respectively.

Conclusions:

Cell block technique by AAF fixative is a simple, inexpensive procedure. Cell block method allows the recovery and processing of minute amounts of cellular material, facilitating better classification of tumor when reviewed along with cytological smears, the ability to obtain many sections for immunostains and other studies to be performed akin to paraffin sections produced in histopathology.

The State of Cell Blocks and Ancillary Testing: Past, Present, and Future

Cell blocks are an integral part of cytology, but their utility is recognized probably more now than ever before, largely owing to the significant role they play in ancillary testing, particularly molecular diagnostics. Modifications to improve the cell block method initially introduced more than a century ago have been made over the years. Though their value is acknowledged and they are widely used across laboratories, cell block preparations are not standardized and results of ancillary testing performed on them are inconsistent. This article reviews the state of cell blocks-summarizes the more common, currently available and used methods and their corresponding advantages and shortcomings, outlines the role of alternative techniques (eg, smears), and proposes methods to optimize results.

Fine-Needle Aspiration with Immunohistochemistry Using a Modified Scrape Cell Block Technique for the Diagnosis of Thyroid and Parathyroid Nodules

OBJECTIVE

To evaluate the diagnostic accuracy of a modified scrape cell block (SCB) technique in a large series of patients. The technique was especially developed and tested for fine-needle aspiration of thyroid and parathyroid nodules.

STUDY DESIGN

Eighty-two ultrasound-guided fine-needle aspiration specimens with the sonographic aspect of a thyroid (n = 33) or a possible parathyroid nodule (n = 49) were studied. Immunohistochemistry (IHC) was used on cell blocks containing plasma, thromboplastin, and selected 3-dimensional cell aggregates scraped off Papanicolaou-stained smears. Antibodies for chromogranin A, thyroglobulin, parathyroid hormone, calcitonin, and carcinoembryonic antibody (CEA) were used. In cases of reduced immunosensitivity or suspected metastases or rare primary tumors, additional IHC markers were employed.

RESULTS

Chromogranin A was expressed in all 28 parathyroid adenomas (PA), in 7 of 8 hyperplastic parathyroid glands, and in 13 of 14 medullary thyroid carcinomas (MTC). When combining positivity for chromogranin A and calcitonin/CEA, the specificity for the detection of MTC was 100%. Parathyroid hormone was expressed in 26 of 36 parathyroid nodules (72.2%). When combining follicular microarchitecture and expression of chromogranin A, the specificity for the detection of parathyroid tissue was 97%.

CONCLUSION

With the modified SCB technique, accurate cytological diagnoses were obtained in 97.6% of 82 patients.

Characterizing specimen quality of cell block samples in an era of personalized diagnostics: analysis of 221 lymph node fine-needle aspirations

INTRODUCTION

Cell block (CB) preparations of fine-needle aspirates (FNAs) are utilized for patient management, which requires retention of representative material on slides. Personalized medicine demands quality CB specimens. There is no standard protocol for CB preparation, often resulting in suboptimal slides. The utility of using two CB slides in lymph node (LN) FNA cases was investigated.

MATERIALS AND METHODS

We cut 10 serial sections from each CB, slides 1 and 5 are stained and considered the first and second cuts, respectively; the remaining slides are reserved for ancillary studies. Hematoxylin and eosin-stained CBs of 221 consecutive LN FNA cases were reviewed; qualitative and quantitative assessment of diagnostic value was made on sections 1 and 5.

RESULTS

Of the 221 cases, 46.1% (102) had comparable diagnostic cellularity (equally representative) on both slides, whereas 26.7% (59) and 27.1% (60) had more representative material on the first and second cuts, respectively (P = 0.52). Differences between the representativeness of first and second CB cuts of intrathoracic lymph nodes were minor (n = 192, P = 0.065). Differences between the first and the second slide representativeness of superficial (n = 22, P = 0.98) and intra-abdominal lymph nodes (n = 7, P = 0.38) are limited because of small sample sizes.

CONCLUSION

One CB cut can be suboptimal for diagnosis. In our study, inclusion of a second slide increases equal representativeness from 46.1% to 73.2%. These limited observations recognize the need for additional investigations regarding the collection and preparation of CBs.

Immunocytochemistry: It's role in diagnosis of undifferentiated neoplasms by fine needle aspiration cytology

Background:

Fine needle aspiration cytology (FNAC) is a rapid, cheap and reliable method for diagnosing any accessible lesion. However, there remains a group of malignant undifferentiated neoplasms, which can only be categorized with the help of immunocytochemistry (ICC). The categorization is important due to their vast difference in treatment and prognosis.

Aim:

To evaluate the effectiveness of ICC in categorizing the undifferentiated neoplasms diagnosed on routine FNAC smears.

Materials and Methods:

Thirty six cases of undifferentiated neoplasms were selected from a group of total 78 cytology cases of undifferentiated tumors from different sites like head and neck, lymph node, soft tissue etc. These were then subjected to a panel of ICC markers based on the clinical and cytomorphological features.

Results:

Of these, 21 were simple, ten were computerized tomography guided and five were ultrasound guided FNACs respectively. All the 78 cases were confirmed by histopathological examination and immunohistochemistry. Of the 36 cytological cases, final diagnosis correlated in 30 cases histologically. The six cases were incorrect either due to inadequate material on the smears (three cases) or false positive staining (three cases).

Conclusions:

Our study found that ICC is a sensitive and specific method for early and definitive diagnosis of undifferentiated neoplasms. However, selection of antibodies must be judicious to make it cost effective.

Antigen retrieval immunohistochemistry: review and future prospects in research and diagnosis over two decades

As a review for the 20th anniversary of publishing the antigen retrieval (AR) technique in this journal, the authors intend briefly to summarize developments in AR-immunohistochemistry (IHC)-based research and diagnostics, with particular emphasis on current challenges and future research directions. Over the past 20 years, the efforts of many different investigators have coalesced in extending the AR approach to all areas of anatomic pathology diagnosis and research and further have led to AR-based protein extraction techniques and tissue-based proteomics. As a result, formalin-fixed paraffin-embedded (FFPE) archival tissue collections are now seen as a literal treasure of materials for clinical and translational research to an extent unimaginable just two decades ago. Further research in AR-IHC is likely to focus on tissue proteomics, developing a more efficient protocol for protein extraction from FFPE tissue based on the AR principle, and combining the proteomics approach with AR-IHC to establish a practical, sophisticated platform for identifying and using biomarkers in personalized medicine.

Diagnosis of hepatocellular carcinoma: fine needle aspiration cytology or needle core biopsy

Needle core biopsy (NCB) has been the standard procedure for histopathologic diagnosis of hepatic lesions for more than 50 years. In recent years fine needle aspiration cytology (FNAC) has emerged as a minimally invasive, relatively inexpensive and a rapid method of pathologic evaluation of primary or metastatic hepatic masses. The specificity and the positive predictive value of FNAC is very high however, the sensitivity of the procedure widely ranges between 67% to 93%. The two major areas of diagnostic difficulties are differentiation of benign and non-neoplastic hepatic nodules from well differentiated HCC and identification of obviously malignant cells as HCC, cholangiocarcinoma, or metastasis. Preparation of cell blocks, immunohistochemical stains and application of other ancillary techniques are often helpful in difficult cases. In presence of characteristic features a diagnosis of HCC can be established on FNAC however, a negative result does not exclude malignancy. The role of pathologic diagnosis in the assessment of large hepatic masses is well established however, its role in the evaluation of small hepatic nodules (<3 cm) detected during surveillance of high risk patients is still evolving. Considering the overall advantages and cost-analysis, FNAC can be suggested as the initial method of choice for evaluation of hepatic masses in most clinical settings. However, the final choice of the diagnostic procedure should be decided on the basis of working clinical diagnosis and the institutional experience.

Routine use of ThinPrep method in fine-needle aspiration material as an adjunct to standard smears

The purpose of this study was to evaluate the efficacy of routine use of ThinPrep in fine-needle aspiration (FNA) material as an adjunct to standard smears. We reviewed 50 consecutive, satisfactory-for-evaluation FNA materials in which ThinPrep slides were obtained. In each case, Diff-Quik-stained and Papanicolaou-stained smears were initially prepared, and the ThinPrep slide was made from the needle/syringe rinse. Smears and ThinPrep slides were evaluated for the presence of diagnostic material. In addition, the following questions were addressed: could the final diagnosis be made based on smears only, and did the ThinPrep method add any additional information to the diagnosis? Smears were satisfactory for evaluation in 49/50 cases, and in one case diagnostic material was present on the ThinPrep slide only. Thirty-two out of 50 ThinPrep slides contained material sufficient for evaluation. In 46/50 (92%) cases, final diagnoses could be made based on smears only. In 2 cases, ThinPrep slides showed additional diagnostic material, and in another 2 cases were critical for the diagnosis. The routine use of ThinPrep as an adjunct preparatory method to FNA material is not justified, and is associated with an additional, potentially nonreimbursable cost.