Cellient™ automated cell block versus traditional cell block preparation: a comparison of morphologic features and immunohistochemical staining

Quality Assurance in Immunocytochemistry: A Review and Practical Considerations

BACKGROUND

Cytological samples play a critical role in diagnosing advanced-stage tumors and those arising in difficult-to-reach anatomical sites such as the pancreatobiliary tract, lung, thyroid, suprarenal, pelvis, and others such as salivary glands. These samples are often the only available material for accurate diagnosis and for performing ancillary studies, such as immunocytochemistry (ICC) or the detection of molecular biomarkers.

SUMMARY

While the use of immunohistochemistry is well established and standardized on formalin-fixed-paraffin-embedded histological tissue, in cytological samples, it presents unique challenges. Methods used for obtaining and processing these specimens are complex and are not standardized among laboratories. Moreover, there is also diversity in the types of cytological samples potentially suitable for ICC.

KEY MESSAGES

This review explores the current landscape of ICC practices in European and North American laboratories, highlighting variability in methods and the need for standardization to ensure reliable results and reproducibility of ICC on cytological specimens.

Reevaluation of ovarian cyst fine-needle aspiration cytology: A 10-year institutional experience

OBJECTIVES

Fine-needle aspiration (FNA) of ovarian cyst fluid remains useful for certain clinical circumstances despite low sensitivity and potential safety concerns. The current study aimed to reevaluate the performance of ovarian cystic fluid cytology following American College of Obstetricians and Gynecologists guidelines using a single-institution cohort.

METHODS

A total of 507 ovarian cyst FNA cases from 2013 to 2023 were reviewed. Patients' demographics and clinical and radiologic information were collected through the electronic database. The performance was calculated using corresponding surgical pathology diagnosis as the gold standard.

RESULTS

Overall, cytologic diagnoses were nondiagnostic (ND), negative for malignancy (NFM), atypical (ATY), suspicious for malignancy (SFM), and malignant (M) in 5 (1.0%), 478 (94.3%), 14 (2.7%), 2 (0.4%), and 8 (1.6%) cases, respectively. Among 349 specimens (68.8%) that had a corresponding surgical pathology, the rate of malignancy (including borderline tumors) was 1.2% (4 of 325) in NFM, 72.7% in ATY (8 of 11), and 100% in both SFM (2 of 2) and M (8 of 8) specimens. Considering NFM and ATY as negative results and SFM and M as positive results, overall, the sensitivity of ovarian cystic fluid cytology was 45.4% and the specificity was 100%.

CONCLUSIONS

As an uncommon test, ovarian cystic fluid cytology has moderate sensitivity and high specificity. Despite limitations, ovarian cystic FNA cytology remains a valuable diagnostic tool in certain aspects.

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.

The Value and Limitations of Cell Blocks in Endobronchial Ultrasound-Guided Fine-Needle Aspiration Cytology: Experience of a Tertiary Care Center in North India

Background:

Endobronchial ultrasound (EBUS)-guided fine-needle aspiration cytology (FNAC) is recommended for diagnosing bronchial neoplasms and evaluating mediastinal lymph nodes. However, it may not be possible to subtype or definitely categorize many bronchial neoplasms on FNAC smears alone. Obtaining adequate diagnostic material is often a problem. In such cases, cell blocks made from FNAC material may serve as a useful adjunct. Aim: To study the value and limitations of cell blocks in adding diagnostic information to EBUS guided FNAC smears.

Material and Methods:

One hundred and eighty-five cases of EBUS guided FNAC having concomitant cell blocks were reviewed. The cases were evaluated for the extent of adequacy, of definite benign/malignant categorization and of definite subtyping in malignant tumors in these cases. The proportion of cases in which cell blocks added information to FNAC smears alone for the above parameters were calculated.

Results:

Cell blocks provided additional information in 31 out of 185 cases. Cell blocks were necessary for subtyping 24/59 malignant tumors, definite categorization into benign and malignant in 10/140 adequate samples, and increasing adequacy in 6/185 total samples. A total of 45 samples were inadequate in spite of adding information from cell blocks to smears.

Conclusion:

Cell blocks added clinically significant information to EBUS guided FNAC and should be used routinely. To make it more useful, alternative methods of cell block preparation (including proprietary methods) may be evaluated.

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.

Analysis of Vitreous Samples by the Cellient® Automated Cell Block System: A Six-year Review of Specimens in a Uveitis Population

Purpose: To further evaluate the value of a standardized method to analyze vitreous samples using the Cellient® automated cell block system in the diagnosis of unsolved uveitis.Methods: Six hundred sixty-four pure vitreous samples obtained from patients with unsolved uveitis between March 2012 and May 2018 at University Hospitals Leuven, fixed in PreservCyt® and processed by the Cellient tissue processor, were included in the study.Results: In 86.3% of the cases, sufficient material was found for diagnosis. A diagnosis of acute inflammation was made in 20.2% of the cases. In 34.0% of the cases, the diagnosis was chronic active inflammation; in 26.5%, low-grade inflammation; and in 5.6%, a malignant process.Conclusion: Our standardized protocol can be used to diagnose endophthalmitis, lymphoma, granulomatous disease, inactive and storage disease, and metastatic infiltration. Cellient analysis of vitreous specimens had a diagnostic yield of 86.3% in unsolved uveitis cases.

The Milan system for reporting salivary gland cytopathology: Single center experience with cell blocks

BACKGROUND

Salivary gland fine needle aspiration (FNA) has a well-established role in the evaluation of salivary gland lesions. The Milan system for reporting salivary gland cytopathology (MSRSGC) was developed in 2018 to accomplish a standardized reporting across institutions. This classification is predominantly based on the use of direct smears. This single center study aims to evaluate and further validate the MSRSGC based on the sole use of cell blocks and carry out a risk assessment based on follow up histopathology.

METHODS

A total of 359 FNA specimens from 343 patients processed as cell blocks between 2012 and 2018 were retrieved, with histologic follow-up available in 235 cases. The cytological diagnosis were reclassified according to the MSRSGC categories: non-diagnostic, non-neoplastic, atypia of undetermined significance (AUS), benign neoplasm, salivary gland neoplasm of uncertain malignant potential (SUMP), suspicious for malignancy (SFM), and malignant. The use of ancillary immunohistochemistry or molecular testing was recorded. The risk of malignancy (ROM) was calculated for each diagnostic category.

RESULTS

Overall accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were 92.9%, 75.9%, 97.9%, 91.7%, and 95%, respectively. The ROM for the non-diagnostic, non-neoplastic, AUS benign neoplasms, SUMP, SFM and malignant categories were 13.8%, 14.2%, 30%, 6.3%, 20.8%, 60%, and 100%, respectively.

CONCLUSION

This large single center retrospective series further validates the MSRSGC. The proposed diagnostic classification is reproducible with use of cell blocks. Discrepancies in number of cases per category and ROM are based on cross-institution variabilities, pre-FNA diagnostics (imaging) and ancillary tests.

Immunocytochemistry of cytology specimens for predictive biomarkers in lung cancer

With a growing number of predictive biomarkers that have emerged in non-small cell lung carcinoma (NSCLC), there has been a paradigm shift in the management of these patients. Of the various predictive biomarker testing methods, immunohistochemistry (IHC) is the most widely available, cost-effective, and commonly used methods. However, most predictive IHC assays are validated primarily on formalin-fixed paraffin-embedded (FFPE) histologic tissue samples and translating these assays to cytologic specimens requires additional and rigorous validation. This is part due to the lack of standardized processing protocols in cytology resulting in a variety of preanalytic variables that can impact the antigenicity of antibodies used for predictive biomarker testing. The review article discusses the various preanalytical and analytical factors that impact immunocytochemistry (ICC) in cytologic specimens and summarizes the current published literature on ALK, ROS1, PD-L1, and other predictive biomarker ICC in cytology.

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.

CytoLyt fixation significantly inhibits MIB1 immunoreactivity whereas alternative Ki-67 clone 30-9 is not susceptible to the inhibition: Critical diagnostic implications

BACKGROUND

The Ki-67 proliferation marker has multiple diagnostic and prognostic applications. Although several clones to the Ki-67 antigen are commercially available, the MIB1 clone is widely recommended in the surgical pathology literature for neuroendocrine tumors. In our cytopathology practice, we have encountered unexpectedly low MIB1 immunoreactivity in CytoLyt-fixed cell blocks (CBs). The current study evaluated the impact of fixatives, CB processing, and immunocytochemical (ICC) procedures on Ki-67 immunoreactivity.

METHODS

Test CBs were prepared from freshly resected tumors, and multiple variables in the MIB1 ICC procedure were tested, including CytoLyt versus formalin collection media, MIB1 versus other Ki-67 clones including 30-9, and other variables. MIB1 versus Ki-67 30-9 clones were tested in parallel on CytoLyt-fixed CBs from clinical samples of small cell lung carcinoma (SCLC).

RESULTS

In the test CBs (n = 10), the mean MIB1 labeling index was 10% in CytoLyt versus 47% in formalin (P = .0116), with a mean loss of reactivity in matched CBs of 37% (up to 70%). None of the procedure modifications tested in 223 individual ICC reactions recovered MIB1 reactivity in CytoLyt except for switching to the Ki-67 30-9 antibody. In CytoLyt-fixed SCLC samples (n = 14), the Ki-67 30-9 antibody demonstrated expected ranges of reactivity (mean, 83%; range, 60%-100%), whereas MIB1 demonstrated markedly inhibited labeling (mean, 60%; range, 10%-95%) (P = .0058).

CONCLUSIONS

CytoLyt fixation substantially inhibits MIB1 immunoreactivity, whereas the Ki-67 30-9 clone is not susceptible to inhibition. Markedly discrepant MIB1 reactivity may present a pitfall in the diagnosis of SCLC and may lead to the incorrect prognostic stratification of other tumor types. For laboratories using CytoLyt, we recommend using the Ki-67 30-9 antibody rather than the MIB1 antibody.

Immunocytochemistry for predictive biomarker testing in lung cancer cytology

With an escalating number of predictive biomarkers emerging in non-small cell lung carcinoma (NSCLC), immunohistochemistry (IHC) is being used as a rapid and cost-effective tool for the screening and detection of many of these markers. In particular, robust IHC assays performed on formalin-fixed, paraffin-embedded (FFPE) tumor tissue are widely used as surrogate markers for ALK and ROS1 rearrangements and for detecting programmed death ligand 1 (PD-L1) expression in patients with advanced NSCLC; in addition, they have become essential for treatment decisions. Cytology samples represent the only source of tumor in a significant proportion of patients with inoperable NSCLC, and there is increasing demand for predictive biomarker testing on them. However, the wide variation in the types of cytology samples and their preparatory methods, the use of alcohol-based fixatives that interfere with immunochemistry results, the difficulty in procurement of cytology-specific controls, and the uncertainty regarding test validity have resulted in underutilization of cytology material for predictive immunocytochemistry (ICC), and most cytopathologists limit such testing to FFPE cell blocks (CBs). The purpose of this review is to: 1) analyze various preanalytical, analytical, and postanalytical factors influencing ICC results; 2) discuss measures for validation of ICC protocols; and 3) summarize published data on predictive ICC for ALK, ROS1, EGFR gene alterations and PD-L1 expression on lung cancer cytology. Based on our experience and from a review of the literature, we conclude that cytology specimens are in principal suitable for predictive ICC, but proper optimization and rigorous quality control for high-quality staining are essential, particularly for non-CB preparations.

Suitability of the CellientTM cell block method for diagnosing soft tissue and bone tumors

BACKGROUND

The diagnosis of tumors of soft tissue and bone (STB) heavily relies on histological biopsies, whereas cytology is not widely used. Cellient^TM cell blocks often contain small tissue fragments. In addition to Hematoxylin and Eosin (H&E) interpretation of histological features, immunohistochemistry (IHC) can be applied after optimization of protocols. The objective of this retrospective study was to see whether this cytological technique allowed us to make a precise diagnosis of STB tumors.

METHODS

Our study cohort consisted of 20 consecutive STB tumors, 9 fine-needle aspiration (FNAC) samples, and 11 endoscopic ultrasonography (EUS) FNACs and included 8 primary tumors and 12 recurrences or metastases of known STB tumors.

RESULTS

In all 20 cases, H&E stained sections revealed that diagnostically relevant histological and cytological features could be examined properly. In the group of 8 primary tumors, IHC performed on Cellient^TM material provided clinically important information in all cases. For instance, gastrointestinal stromal tumor (GIST) was positive for CD117 and DOG-1 and a PEComa showed positive IHC for actin, desmin, and HMB-45. In the group of 12 secondary tumors, SATB2 was visualized in metastatic osteosarcoma, whereas expression of S-100 was present in 2 secondary chondrosarcomas. Metastatic chordoma could be confirmed by brachyury expression. Two metastatic alveolar rhabdomyosarcomas were myf4 positive, a metastasis of a gynecologic leiomyosarcoma was positive for actin and estrogen receptor (ER) and a recurrent dermatofibrosarcoma protuberans expressed CD34.

CONCLUSION

In the proper clinical context, including clinical presentation with imaging studies, the Cellient^TM cell block technique has great potential for the diagnosis of STB tumors.

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.

The utility of cellient cell blocks in low-cellularity thyroid fine needle aspiration biopsies

BACKGROUND

Low cellularity can be problematic in thyroid fine needle aspiration (FNA) biopsies. The Cellient cell block (CB) system has been reported to improve cell recovery compared to traditional methods. Therefore, we studied the utility of Cellient CBs in the evaluation of thyroid FNAs, with an emphasis on low-cellularity specimens.

METHODS

ThinPrep slides were prepared from thyroid FNAs submitted in Cytolyt. After assessment using TBSRTC criteria, Cellient CBs were requested on samples with residual FNA material and an initial cytologic impression of non-diagnostic, AUS/FLUS, and on apparently benign samples with marginally adequate cellularity. The contribution of the CB findings to the final diagnosis was assessed.

RESULTS

965 cases of paired ThinPrep and CB sections were examined. Overall, the cell block findings resulted in a change of the initial ThinPrep impression in 15% (n = 148) of cases. The vast majority of these changed cases were initially inadequate for interpretation, and specifically, 31% (n = 123) of the non-diagnostic ThinPrep samples became diagnostic with a CB. The cell block findings contributed to a change in diagnosis in 8% (n = 23) of AUS/FLUS cases, and in less than 1% of low-cellularity benign samples.

CONCLUSION

The use of CBs in low-cellularity thyroid FNAs has not been well described. In this study, we found that the contribution of CBs in this setting varied by TBSRTC category. Specifically, the samples that benefited most were initially non-diagnostic specimens and select cases of AUS/FLUS, while low-cellularity benign samples gained very little additional information. Diagn. Cytopathol. 2016;44:737-741. © 2016 Wiley Periodicals, Inc.

Cell and Tissue Display: An Alternative Multipurpose Tool for Microscopy

We developed a method, termed Cell and Tissue Display (CTD), for embedding 16 or more different tissue samples in multi-compartment agarose blocks. The CTD-generated blocks allow uniform multiplexing of cell lines and small tissue fragments within a single histologic block. The distribution of individual cells within the CTD blocks is improved, likely because the individual agarose compartments are small and uniform. The composition of each CTD block can be customized based on intended use. Some potential uses of CTD histologic blocks include improved sectioning of small tissue fragments, such as needle biopsy specimens or punch biopsies; multiplexing of tissue fragments within a single block; and the generation of control slides for laboratory proficiency testing. .

Cell Block Preparation versus Liquid-Based Thin-Layer Cervical Cytology: A Comparative Study Evaluating Human Papillomavirus Testing by Hybrid Capture-2/Cervista, in situ Hybridization and p16 Immunohistochemistry

OBJECTIVE

Cell block (CB) preparations from residual liquid-based Pap samples have been shown to be of diagnostic value. In this study we evaluated human papillomavirus (HPV) in situ hybridization (ISH) and p16 immunohistochemistry (IHC) on CB preparations and compared the results with the primary diagnosis and standard HPV tests.

DESIGN

In total, 197 HE-stained CB slides prepared from CBs from residual Pap samples (152 ASCUS, 2 ASC-H, 32 LGSIL, 4 HGSIL, 1 AGUS and 6 normal) were analyzed. Hybrid Capture-2 (HC-2)/Cervista testing and HPV ISH and p16 IHC were performed on the CB samples. The test performance characteristics were compared with HPV and p16 assay performances.

RESULTS

The cellular architecture was well maintained in CBs with excellent consistency. HPV ISH testing had an excellent concordance with the HC-2/Cervista methods (85%) with high sensitivity (82.6%; 95% CI 75.9, 89.4) and specificity (89.3%). Of all the p16 tests, 38% were positive (60 out of 159 samples). The overall concordance between p16 and HC-2/Cervista (64%), or between p16 and ISH (68%), was lower than the concordance between ISH and HC-2/Cervista (85%).

CONCLUSIONS

HPV ISH and p16 IHC testing is feasible, cost effective and practical. A combination of the two tests would ultimately improve diagnostic accuracy, leading to better therapeutic decisions.

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.

Cell-block procedure in endoscopic ultrasound-guided-fine-needle-aspiration of gastrointestinal solid neoplastic lesions

In the present review we have analyzed the clinical applications of endoscopic ultrasound-guided-fine-needle-aspiration (EUS-FNA) and the methodological aspects obtained by cell-block procedure (CBP) in the diagnostic approach to the gastrointestinal neoplastic pathology. CBP showed numerous advantages in comparison to the cytologic routine smears; in particular, better preservation of cell architecture, achievement of routine haematoxylin-eosin staining equivalent to histological slides and possibility to perform immunohistochemistry or molecular analyses represented the most evident reasons to choose this method. Moreover, by this approach, the differential diagnosis of solid gastrointestinal neoplasias may be more easily achieved and the background of contaminant non-neoplastic gastrointestinal avoided. Finally, biological samples collected by EUS-FNA CBP-assisted should be investigated in order to identify and quantify further potential molecular markers.

Whole-Slide Imaging of Pap Cellblock Preparations Is a Potentially Valid Screening Method

OBJECTIVE

To date, the impact of digital imaging on routine cytology remains far from perfect. Cellblock (CB) preparations from Pap samples have been shown to be diagnostically valuable. We evaluated the validity of utilizing whole-slide imaging (WSI) prepared from Pap CBs as a screening tool.

STUDY DESIGN

A total of 1,110 CB slides prepared from residual Pap samples were analyzed - 563 normal, 282 atypical squamous cells of undetermined significance (ASCUS), 12 atypical squamous cells-cannot exclude high-grade squamous intraepithelial lesion, 188 low-grade squamous intraepithelial lesions (LSIL), 36 high-grade squamous intraepithelial lesions (HSIL), 25 atypical glandular cells of undetermined significance, 1 adenocarcinoma in situ, 2 invasive adenocarcinomas, and 1 squamous cell carcinoma. Virtual slides were obtained using the Aperio system. Test performance characteristics of liquid-based samples and WSI from CB samples were compared.

RESULTS

Average sensitivity and specificity of the five WSI reviewers was 58.3 and 85.1% for ASCUS, respectively, 54.1 and 93.9% for LSIL, and 51.8 and 98.8% for HSIL. Overall WSI sensitivity and specificity for detecting lesions was 82.1 and 86.2%, respectively. Agreement (kappa values) between WSI reviewers was 0.56 for ASCUS, 0.69 for LSIL, 0.67 for HSIL, and 0.74 for negative samples.

CONCLUSIONS

WSI of CB preparations is a feasible method to achieve high-quality specimen preparations. It is as sensitive as liquid-based methods and appears to be highly specific for the detection of LSIL and HSIL.

Comparison of the Cellient(™) automated cell block system and agar cell block method

OBJECTIVE

To compare the Cellient(TM) automated cell block system with the agar cell block method in terms of quantity and quality of diagnostic material and morphological, histochemical and immunocytochemical features.

MATERIALS AND METHODS

Cell blocks were prepared from 100 effusion samples using the agar method and Cellient system, and routinely sectioned and stained for haematoxylin and eosin and periodic acid-Schiff with diastase (PASD). A preliminary immunocytochemical study was performed on selected cases (27/100 cases). Sections were evaluated using a three-point grading system to compare a set of morphological parameters. Statistical analysis was performed using Fisher's exact test.

RESULTS

Parameters assessing cellularity, presence of single cells and definition of nuclear membrane, nucleoli, chromatin and cytoplasm showed a statistically significant improvement on Cellient cell blocks compared with agar cell blocks (P < 0.05). No significant difference was seen for definition of cell groups, PASD staining or the intensity or clarity of immunocytochemical staining. A discrepant immunocytochemistry (ICC) result was seen in 21% (13/63) of immunostains.

CONCLUSION

The Cellient technique is comparable with the agar method, with statistically significant results achieved for important morphological features. It demonstrates potential as an alternative cell block preparation method which is relevant for the rapid processing of fine needle aspiration samples, malignant effusions and low-cellularity specimens, where optimal cell morphology and architecture are essential. Further investigation is required to optimize immunocytochemical staining using the Cellient method.

Preparation of compact agarose cell blocks from the residues of liquid-based cytology samples

Background

Inevitable loss of diagnostic material should be minimized during cell block preparation. We introduce a modified agarose cell block technique that enables the synthesis of compact cell blocks by using the entirety of a cell pellet without the loss of diagnostic material during cell block preparations. The feasibility of this technique is illustrated by high-throughput immunocytochemistry using high-density cell block microarray (CMA).

Methods

The cell pellets of Sure- Path residues were pre-embedded in ultra-low gelling temperature agarose gel and re-embedded in standard agarose gel. They were fixed, processed, and embedded in paraffin using the same method as tissue sample processing. The resulting agarose cell blocks were trimmed and represented on a CMA for high-throughput analysis using immunocytochemical staining.

Results

The SurePath residues were effectively and entirely incorporated into compact agarose cell buttons and embedded in paraffin. Sections of the agarose cell blocks revealed cellularities that correlated well with corresponding SurePath smears and had immunocytochemical features that were sufficient for diagnosis of difficult cases.

Conclusions

This agarose-based compact cell block technique enables preparation of high-quality cell blocks by using up the residual SurePath samples without loss of diagnostic material during cell block preparation.

Cell blocks in cytopathology: a review of preparative methods, utility in diagnosis and role in ancillary studies

The cell block (CB) is a routine procedure in cytopathology that has gained importance because of its pivotal role in diagnosis and ancillary studies. There is no precise review in the published literature that deals with the various methods of preparation of CB, its utility in diagnosis, immunocytochemistry (ICC) or molecular testing, and its drawbacks. An extensive literature search on CB in cytology using internet search engines was performed for this review employing the following keywords: cell block, cytoblock, cytology, cytopathology, methods, preparation, fixatives, diagnostic yield, ancillary and molecular studies. Ever since its introduction more than a century ago, the CB technique has undergone numerous modifications to improve the quality of the procedure; however, the overall principle remains the same in each method. CBs can be prepared from virtually all varieties of cytological samples. In today's era of personalized medicine, cytological specimens, including CBs, augment the utility of cytological samples in analysing the molecular alterations as effectively as surgical biopsies or resection specimens. With the availability of molecular targeted therapy for many cancers, a large number of recent studies have used cytological material or CBs for molecular characterization. The various techniques of CB preparation with different fixatives, their advantages and limitations, and issues of diagnostic yield are discussed in this review.

A new and standardized method to sample and analyse vitreous samples by the Cellient automated cell block system

PURPOSE

In this prospective study, a universal protocol for sampling and analysing vitreous material was investigated. Vitreous biopsies are difficult to handle because of the paucity of cells and the gelatinous structure of the vitreous. Histopathological analysis of the vitreous is useful in difficult uveitis cases to differentiate uveitis from lymphoma or infection and to define the type of cellular reaction.

METHODS

Hundred consecutive vitreous samples were analysed with the Cellient tissue processor (Hologic). This machine is a fully automated processor starting from a specified container with PreservCyt (fixative fluid) with cells to paraffin. Cytology was compared with fixatives Cytolyt (contains a mucolyticum) and PreservCyt. Routine histochemical and immunostainings were evaluated.

RESULTS

In 92% of the cases, sufficient material was found for diagnosis. In 14%, a Cytolyt wash was necessary to prevent clotting of the tubes in the Cellient due to the viscosity of the sample. In 23%, the diagnosis was an acute inflammation (presence of granulocytes); in 33%, chronic active inflammation (presence of T lymphocytes); in 33%, low-grade inflammation (presence of CD68 cells, without T lymphocytes); and in 3%, a malignant process.

CONCLUSION

A standardized protocol for sampling and handling vitreous biopsies, fixing in PreservCyt and processing by the Cellient gives a satisfactory result in morphology, number of cells and possibility of immuno-histochemical stainings. The diagnosis can be established or confirmed in more than 90% of cases.

Automated Cellient(™) cytoblocks: better, stronger, faster?

OBJECTIVE

Cytoblocks (CBs), or cell blocks, provide additional morphological detail and a platform for immunocytochemistry (ICC) in cytopathology. The Cellient(™) system produces CBs in 45 minutes using methanol fixation, compared with traditional CBs, which require overnight formalin fixation. This study compares Cellient and traditional CB methods in terms of cellularity, morphology and immunoreactivity, evaluates the potential to add formalin fixation to the Cellient method for ICC studies and determines the optimal sectioning depth for maximal cellularity in Cellient CBs.

METHODS

One hundred and sixty CBs were prepared from 40 cytology samples (32 malignant, eight benign) using four processing methods: (A) traditional; (B) Cellient (methanol fixation); (C) Cellient using additional formalin fixation for 30 minutes; (D) Cellient using additional formalin fixation for 60 minutes. Haematoxylin and eosin-stained sections were assessed for cellularity and morphology. ICC was assessed on 14 cases with a panel of antibodies. Three additional Cellient samples were serially sectioned to determine the optimal sectioning depth. Scoring was performed by two independent, blinded reviewers.

RESULTS

For malignant cases, morphology was superior with Cellient relative to traditional CBs (P < 0.001). Cellularity was comparable across all methods. ICC was excellent in all groups and the addition of formalin at any stage during the Cellient process did not influence the staining quality. Serial sectioning through Cellient CBs showed optimum cellularity at 30-40 μm with at least 27 sections obtainable.

CONCLUSIONS

Cellient CBs provide superior morphology to traditional CBs and, if required, formalin fixation may be added to the Cellient process for ICC. Optimal Cellient CB cellularity is achieved at 30-40 μm, which will impact on the handling of cases in daily practice.

Determination of HER2/neu status: a pilot study comparing HER2/neu dual in situ hybridization DNA probe cocktail assay performed on cell blocks to immunohistochemisty and fluorescence in situ hybridization performed on histologic specimens

CONTEXT

Validation of new methodologies for determining human epidermal growth factor receptor 2 gene (HER2/neu) amplification status is crucial for advancing the standard of care and determining treatment for patients with primary and/or metastatic breast carcinoma.

OBJECTIVE

To compare results of HER2/neu gene amplification status by 2-color chromogenic in situ hybridization (ISH) on cell block material to HER2/neu status by immunohistochemistry (IHC) and/or fluorescence in situ hybridization (FISH) in the corresponding resection specimen or previous biopsy specimen.

DESIGN

Formalin, thrombin, and Cellient cell blocks were prepared from cytologic samples obtained from resection specimens from 27 patients with invasive breast carcinoma. In situ hybridization was performed on cell block sections from 18 of the collected cases, on both the Ventana BenchMark ULTRA and the Ventana BenchMark XT, and the HER2/neu gene amplification status was determined. This was then compared to the HER2/neu status by IHC and/or FISH in the resection specimen or previous biopsy specimen.

RESULTS

Comparison of HER2/neu status by ISH on the quantifiable cell block sections showed 100% correlation with the HER2/neu status determined by IHC or FISH in the corresponding histologic specimens. The results from thrombin and formalin cell blocks were statistically superior to the results from Cellient cell blocks on both Ventana instruments.

CONCLUSIONS

While further validation and study are needed, preliminary results show that the HER2/neu gene amplification status of breast carcinomas can reliably be determined on thrombin and formalin cell block material by using ISH. More consistent staining and better signal integrity was obtained with the Ventana BenchMark ULTRA than the BenchMark XT.

Immunohistochemistry practices of cytopathology laboratories: a survey of participants in the College of American Pathologists Nongynecologic Cytopathology Education Program

CONTEXT

Immunohistochemistry (IHC) is important for cytology but poses special challenges because preanalytic conditions may differ from the conditions of IHC-positive controls.

OBJECTIVE

To broadly survey cytology laboratories to quantify preanalytic platforms for cytology IHC and identify problems with particular platforms or antigens. To discover how validation guidelines for HER2 testing have affected cytology.

DESIGN

A voluntary survey of cytology IHC practices was sent to 1899 cytology laboratories participating in the College of American Pathologists Nongynecologic Cytopathology Education Program in the fall of 2009.

RESULTS

A total of 818 laboratories (43%) responded to the survey by April 2010. Three hundred fourty-five of 791 respondents (44%) performed IHC on cytology specimens. Seventeen different fixation and processing platforms prior to antibody reaction were reported. A total of 59.2% of laboratories reported differences between the platforms for cytology specimens and positive controls, but most (155 of 184; 84%) did not alter antibody dilutions or antigen retrieval for cytology IHC. When asked to name 2 antibodies for which staining conditions differed between cytology and surgical samples, there were 18 responses listing 14 antibodies. A total of 30.6% of laboratories performing IHC offered HER2 testing before publication of the 2007 College of American Pathologists/American Society of Clinical Oncologists guidelines, compared with 33.6% afterward, with increased performance of testing by reference laboratories. Three laboratories validated a nonformalin HER2 platform.

CONCLUSIONS

The platforms for cytology IHC and positive controls differ for most laboratories, yet conditions are uncommonly adjusted for cytology specimens. Except for the unsuitability of air-dried smears for HER2 testing, the survey did not reveal evidence of systematic problems with any antibody or platform.

Authors attain comparable or slightly higher rates of citation publishing in an open access journal (CytoJournal) compared to traditional cytopathology journals - A five year (2007-2011) experience

BACKGROUND

The era of Open Access (OA) publication, a platform which serves to better disseminate scientific knowledge, is upon us, as more OA journals are in existence than ever before. The idea that peer-reviewed OA publication leads to higher rates of citation has been put forth and shown to be true in several publications. This is a significant benefit to authors and is in addition to another relatively less obvious but highly critical component of the OA charter, i.e. retention of the copyright by the authors in the public domain. In this study, we analyzed the citation rates of OA and traditional non-OA publications specifically for authors in the field of cytopathology.

DESIGN

We compared the citation patterns for authors who had published in both OA and traditional non-OA peer-reviewed, scientific, cytopathology journals. Citations in an OA publication (CytoJournal) were analyzed comparatively with traditional non-OA cytopathology journals (Acta Cytologica, Cancer Cytopathology, Cytopathology, and Diagnostic Cytopathology) using the data from web of science citation analysis site (based on which the impact factors (IF) are calculated). After comparing citations per publication, as well as a time adjusted citation quotient (which takes into account the time since publication), we also analyzed the statistics after excluding the data for meeting abstracts.

RESULTS

Total 28 authors published 314 publications as articles and meeting abstracts (25 authors after excluding the abstracts). The rate of citation and time adjusted citation quotient were higher for OA in the group where abstracts were included (P < 0.05 for both). The rates were also slightly higher for OA than non-OA when the meeting abstracts were excluded, but the difference was statistically insignificant (P = 0.57 and P = 0.45).

CONCLUSION

We observed that for the same author, the publications in the OA journal attained a higher rate of citation than the publications in the traditional non-OA journals in the field of cytopathology over a 5 year period (2007-2011). However, this increase was statistically insignificant if the meeting abstracts were excluded from the analysis. Overall, the rates of citation for OA and non-OA were slightly higher to comparable.

The state of cell block variation and satisfaction in the era of molecular diagnostics and personalized medicine

BACKGROUND

In the recent past, algorithms and recommendations to standardize the morphological, immunohistochemical and molecular classification of lung cancers on cytology specimens have been proposed, and several organizations have recommended cell blocks (CBs) as the preferred modality for molecular testing. Based on the literature, there are several different techniques available for CB preparation-suggesting that there is no standard. The aim of this study was to conduct a survey of CB preparation techniques utilized in various practice settings and analyze current issues, if any.

MATERIALS AND METHODS

A single E-mail with a link to an electronic survey was distributed to members of the American Society of Cytopathology and other pathologists. Questions pertaining to the participants' practice setting and CBs-volume, method, quality and satisfaction-were included.

RESULTS

Of 95 respondents, 90/95 (94%) completed the survey and comprise the study group. Most participants practice in a community hospital/private practice (44%) or academic center (41%). On average, 14 CBs (range 0-50; median 10) are prepared by a laboratory daily. Over 10 methods are utilized: Plasma thrombin (33%), HistoGel (27%), Cellient automated cell block system (8%) and others (31%) respectively. Forty of 90 (44%) respondents are either unsatisfied or sometimes satisfied with their CB quality, with low-cellular yield being the leading cause of dissatisfaction. There was no statistical significance between the three most common CB preparation methods and satisfaction with quality.

DISCUSSION

Many are dissatisfied with their current method of CB preparation, and there is no consistent method to prepare CBs. In today's era of personalized medicine with an increasing array of molecular tests being applied to cytological specimens, there is a need for a standardized protocol for CB optimization to enhance cellularity.

Evaluation of ultrasound-processed rapid cell blocks in the cytopathologic diagnosis of cavity fluids

OBJECTIVE

The technique of conventional cell blocks is rather labor- and time-consuming. The purpose of this study was to generate a convenient and quick manual procedure using ultrasound processing which could be applied in most developing countries and to evaluate its efficacy in the cytopathologic diagnosis of cavity fluids.

STUDY DESIGN

We carried out a rapid cell block procedure using egg albumen as the pre-embedded adjuvant and using ultrasound to accelerate fixation, dehydration, clearing and waxing. The diagnostic efficacy was evaluated as compared with tissue blocks and liquid-based cytology tests (LCTs).

RESULTS

A total of 155 samples underwent rapid cell block detection, and 61 were diagnosed as malignancies. The method was able to produce high-quality formalin-fixed paraffin-embedded cell block sections and has similar diagnostic validity to the LCT. The immunohistochemistry and in situ hybridization staining patterns in rapid cell block sections were similar to those in their tissue block counterparts.

CONCLUSIONS

The ultrasound-processed rapid cell block is a convenient and quick method for cytopathologic diagnosis. We consider it may serve as an effective adjuvant technique for most primary medical institutions.

Overview of nongynecological samples prepared with liquid-based cytology medium

OBJECTIVE

Liquid-based cytology of nongynecological specimens is commonly used in cytology laboratories throughout the world and various processing methods, such as ThinPrep and SurePath, have been reported. The cytological features and performance of liquid-based cytology for various cytology specimens, including body cavity fluids, urine, brushing specimens and fine-needle aspiration of various lesions, were reviewed and compared with the experience of our laboratory and the literature published in PubMed.

STUDY DESIGN

The parameters for the evaluation of liquid-based cytology and conventional smears were described in the various types of specimens. Criteria for the interpretation of nongynecological liquid-based cytology were highlighted to show differences in cell morphology, background and artifacts.

RESULTS

The interpretation requires familiarity with the appearance of liquid-based cytology in the various types of preparations to avoid misdiagnosis.

CONCLUSIONS

Cell blocks can be prepared with specimens preserved in a liquid-based cytology medium and immunocytochemical stains and molecular testing can be successfully performed. These are important adjuncts in order to reach a definitive diagnosis.

Five Top Stories in Cytopathology

Context.—Cytology relies heavily on morphology to make diagnoses, and morphologic criteria have not changed much in recent years. The field is being shaped predominantly by new techniques for imaging and for acquiring and processing samples, advances in molecular diagnosis and therapeutics, and regulatory issues.

Objective.—To review the importance of classical morphology in the future of cytopathology, to identify areas in which cytology is expanding or contracting in its scope, and to identify factors that are shaping the field.

Data Sources.—Literature review.

Conclusions.—Five stories paint a picture in which classical cytomorphology will continue to have essential importance, both for diagnosis and for improving our understanding of cancer biology. New endoscopy and imaging techniques are replacing surgical biopsies with cytology samples. New molecularly targeted therapies offer a chance for cytology to play a major role, but they pose new challenges. New molecular tests have the potential to synergize with, but not replace, morphologic interpretation of thyroid fine-needle aspirations. Ultrasound-guided fine-needle aspiration performed by cytopathologists is opening a new field of “interventional cytopathology” with unique value. For the productive evolution of the field, it will be important for cytopathologists to play an active role in clinical trials that document the ability of cytology to achieve cost-effective health care outcomes.

Effective application of the methanol-based PreservCyt(™) fixative and the Cellient(™) automated cell block processor to diagnostic cytopathology, immunocytochemistry, and molecular biology

We studied the feasibility of immunocytochemistry (ICC), in situ hybridization (ISH), and polymerase chain reaction (PCR) after Cellient(™) automated cell block processing, and tested whether methanol-based PreservCyt(™) fixation could replace formalin fixation, in an attempt to eliminate toxic formaldehyde vapors. Immunostaining with 30 different antibodies was performed on cell blocks from 73 FNA specimens and 42 body cavity fluid specimens prepared by Cellient(™) automated processing that uses the methanol-based fixative (PreservCyt(™) ). For each antibody we evaluated ICC in at least three different cell block specimens and compared it with immunohistochemistry (IHC) in formalin-fixed, paraffin-embedded (FFPE) histological sections from the corresponding tumors. The quality of DNA and RNA in Cellient(™) blocks was analyzed by ISH, applying a SYT gene break-apart assay and EBER probes, respectively. Moreover, DNA quality was analyzed by PCR by using primer sets for DNA products of 100, 200, 300, 400, 500, and 600 base pairs, and evaluated by gel electrophoresis. When compared with IHC results in corresponding FFPE tumor tissue from the same patient, 24 out of 30 antibodies showed concordant ICC results. With FISH, distinctive hybridization signals were observed for SYT DNA sequences and EB virus RNA sequences. With PCR, DNA products, up to 600 base pairs in size, were readily observed after gel electrophoresis. The antibodies that showed concordant immunostaining in Cellient(™) blocks could be applied to diagnostic algorithms that proved to be helpful in the discrimination of major tumor types (carcinoma, lymphoma, melanoma, and germ cell tumors), discrimination of carcinoma subtypes, and determination of primary tumor site in cases of metastatic carcinoma. In a separate study, we found that the application of ICC to this cell block technique provided additional diagnostic and clinically important information in 24% of 100 consecutive cases. The high quality of DNA and RNA in Cellient(™) cell blocks allowed sensitive and specific molecular biologic analysis, in particular FISH and PCR.

The Cellient System for Paraffin Histology Can Be Combined with HPV Testing and Morphotyping the Vaginal Microbiome Thanks to BoonFixing

The Cellient Automated Cell Block System (Hologic) can be used to process cervical scrapes to paraffin sections. For the first study on this subject, cervical scrapes were fixed in the formalin-free fixative BoonFix. This pilot study was limited to cases classified as atypical squamous lesion of unknown significance (ASCUS) and high-grade squamous lesion (HSIL) as diagnosed in the ThinPrep slide. The Cellient paraffin sections were classified into negative, atypical, CIN 1, CIN 2, and CIN 3. Multiple HPV genotypes were encountered in 79% of the scrapes. This study showed that the Cellient system for paraffin sections can be combined with HPV testing thanks to the formalin-free BoonFix. In two additional studies it was shown that such samples can also be used for morphotyping the vaginal microbiome and preparing cytologic ThinPrep slides.

Personalized medicine for non-small-cell lung cancer: implications of recent advances in tissue acquisition for molecular and histologic testing

In light of recent advances in individualized therapy for non-small-cell lung cancer (NSCLC), molecular and histologic profiling is essential for guiding therapeutic decisions. Results of these analyses may have implications for both response (eg, molecular testing for EGFR [epidermal growth factor receptor] mutations) and safety (eg, contraindications for squamous histology) in NSCLC. Most patients with NSCLC present with unresectable advanced disease; therefore, greater emphasis is being placed on minimally invasive tissue acquisition techniques, such as small biopsy and cytology specimens. Due to the need for increasing histologic and molecular information and increasingly smaller tissue sample sizes, efforts must be focused on optimizing tissue acquisition and the development of more sensitive molecular assays. Recent advances in tissue acquisition techniques and specimen preservation may help to address this challenge and lead to enhanced personalized treatment in NSCLC.