Morphologic and immunocytochemical performances of effusion cell blocks prepared using 3 different methods

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.

Comparison of effusion cell block and biopsy immunohistochemistry in mesothelial hyperplasia, mesothelioma, and carcinoma in dogs

BACKGROUND

Determining the cause of effusions is challenging and might require a biopsy. Whether cell blocks from effusions are representative of biopsies requires investigation. A previously developed immunohistochemical panel aids in the differentiation of hyperplastic and neoplastic mesothelium in canine biopsies but has not been investigated in effusions.

OBJECTIVES

The study aimed to assess cell blocks as an alternative to biopsies and determine whether immunohistochemistry helps distinguish hyperplastic mesothelium, mesothelioma, and carcinoma.

METHODS

Effusions and biopsies were collected from five dogs with mesothelial hyperplasia (group MH), six with mesothelioma (group M), and five with carcinoma (group C). Immunohistochemistry (IHC) for cytokeratin, vimentin, Wilm's tumor protein 1 (WT1), desmin, glucose transporter 1 (GLUT1), and insulin-like growth factor II mRNA-binding protein 3 (IMP3) was performed. Sections were scored for staining intensity and the percentage of positively stained cells.

RESULTS

In paired cell blocks and biopsies, vimentin and WT1 staining were positively correlated for intensity and the percentage of positive cells, although not all paired results were identical. The intensity of IMP3 staining in cell blocks was higher in group M than in group C (P = 0.012), and WT1 staining was higher in group MH than in group C (P = 0.020). For biopsies, the intensity of WT1 staining was higher in group MH than in group C (P = 0.031). In group C, WT1 was negative in all cell blocks and biopsies, and desmin was negative in four of five cases.

CONCLUSIONS

IHC results for the cell blocks and biopsies were comparable for potentially useful markers, such as WT1, which helped discriminate between groups. IHC provided additional information, although results were not always definitive. Further studies on a larger population are required.

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.

Immunochemistry in the work-up of mesothelioma and its differential diagnosis and mimickers

The differential diagnosis in cellular effusions with cytological atypia often includes malignant mesothelioma (MM), reactive mesothelial proliferation, and malignancies of metastatic origin, particularly carcinomas. The International Reporting System for Serous Fluid recently established guidelines for reporting MM. In conjunction with the cytomorphologic evaluation, the role of immunochemistry (IC) was emphasized as a very useful tool in the workup of serous fluids, especially with the availability of novel markers. Utilizing a panel of markers, IC allows the characterization of the cells, whether mesothelial or not, and when mesothelial origin is established, IC can frequently assist in delineating its benign or malignant nature. IC can also confirm metastatic disease, allowing the identification of the primary origin in most cases. This review summarizes the current status of IC and its role in the diagnosis of MM and its differential diagnosis in serous fluids.

Cell blocks in veterinary medicine: A comparison of two methods (cell tube and agar) in 52 effusions from dogs and cats

BACKGROUND

Cell blocks are alternative preparations of fluid cytological specimens. They can be used for immunochemical studies as complementary tools or when other techniques (eg, immunocytochemistry, flow cytometry) are not available.

OBJECTIVES

We aimed to provide comparative morphologic, immunohistochemical, and technical features of agar-based cell blocks (ACBs) and cell tube blocks (CTBs) from cavitary effusions.

METHODS

Agar-based cell blocks and CTBs were obtained from canine and feline effusions with neoplastic/atypical cells or with packed cell volumes ≥3%. Cellularity, RBC separation, and cellular features were evaluated on digitalized H&E slides with evaluators blinded to the method. The immunohistochemical intensity and nonspecific background were assessed on pan-cytokeratin and vimentin-stained slides. Overall yield was calculated, and morphologic and immunohistochemical features were compared among paired samples. Technical and cellular features were also described.

RESULTS

Agar-based cell blocks and CTBs yielded evaluable sections in 100% (52/52) and 98% (51/52) of the cases, respectively. Cellularity and RBC separation scores were significantly higher in CTBs. Similar staining intensities were observed, and background staining was more frequently seen in pan-cytokeratin-stained ACBs. Only basic materials and equipment were required for both methods. Agar-based cell block preparations were more operator dependent and difficult to standardize, whereas CTBs were easier to prepare, but laboratory processing was more demanding.

CONCLUSIONS

Both methods can be used to produce good sections for immunohistochemistry staining with no significant differences. Cell tube blocks are beneficial for RBC-rich samples, and little additional training is required to prepare the blocks. Both types of cell blocks are reliable, cost-effective methods that could be introduced in diagnostic laboratories to further characterize canine and feline effusions.

Diagnosis of Hodgkin Lymphoma from Cell Block: A Reliable and Helpful Tool in "Selected" Diagnostic Practice

Background: The diagnosis of lymphoma requires surgical specimens to perform morphological evaluation, immunohistochemical and molecular analyses. Ultrasound-guided fine needle aspiration may represent an appropriate first approach to obtain cytological samples in impalpable lesions and/or in patients unsuitable for surgical procedures. Although cytology has intrinsic limitations, the cell block method may increase the possibility of achieving an accurate diagnosis. Methods: We retrospectively selected a total of 47 ultrasound-guided fine needle aspiration and drainage samples taken from patients with effusion and deep-seated lesions which are clinically suspicious in terms of malignancy. Results: In 27 cases, both cell block and conventional cytology were performed: 21/27 cell blocks were adequate for the diagnosis of lymphoma and suitable for immunocytochemistry and molecular analyses vs. 12/20 samples to which only conventional cytology was applied. Moreover, in five patients we were able to make a diagnosis of Hodgkin lymphoma with the cell block (CB) technique. Conclusions: Contrary to conventional cytology, the cell block method may allow immunocytochemistry and molecular studies providing useful information for the diagnosis and subtypization of lymphoma in patients unsuitable for surgical procedure or with deep-seated lesions or extra-nodal diseases; additionally, it is a daily, simple and helpful approach. Moreover, we describe the usefulness of cell blocks in the diagnosis of Hodgkin lymphoma.

Clinical and laboratory characteristics of lymphoid neoplasms in serous effusions: a single centre experience in China

BACKGROUND

Lymphoid neoplasms in serous effusions are uncommon, and the details of lymphoid neoplasms in serous effusions from China are still unclear.

METHODS

Between January 2004 and December 2019, all patients with lymphoid neoplasms in pleural effusions, ascites, and pericardial effusions in our hospital, were reviewed.

RESULTS

A total of 65 patients with lymphoid neoplasms were collected during this period. The top three neoplasms were diffuse large B-cell lymphoma (DLBCL) (n = 20, 30.7%), myeloma (n = 13, 20.0%), and T-lymphoblastic lymphoma (n = 7, 10.8%). In pleural effusions involving DLBCL, the cytomorphology of DLBCL cells was diverse; most pleural effusions were present during the tumor course (92.9%); bilateral pleural effusions were predominant (57.2%); and the median survival time was only 1.23 months after the effusion. In pleural effusions involving myeloma, 90.9% of cases (10/11) had a high ratio (> 1.0) of immature to mature plasma cells; paraprotein types of IgA (36.4%) and light chain λ (36.4%) were the most frequently found; bilateral pleural effusions were easily found (n = 10, 90.9%); and the median survival time was only 1.4 months after the effusion.

CONCLUSION

In pleural effusions involving DLBCL, most of our patients with effusions are present during the tumor course, and bilateral pleural effusions are predominant. In pleural effusions involving myeloma, the paraprotein types of IgA and light chain λ are the most frequently found, and it has a high ratio of immature to mature plasma cells in pleural effusions.

A case of pulmonary tumor thrombotic microangiopathy associated with lung cancer diagnosed by cell-block immunohistochemistry of pulmonary microvascular cytology

Pulmonary tumor thrombotic microangiopathy (PTTM) is rare but should be considered as a possible diagnosis in patients with cancer. In this case, PTTM induced by lung cancer was more accurately diagnosed using cell block immunohistochemistry of pulmonary microvascular cytology (PMC) because we could confirm that lung adenocarcinoma was the origin of PTTM by the positive result of TTF-1 for atypical cells in PMC. The PMC procedure was minimally invasive and safer than lung biopsy. We believe that the cell block technique of PMC should be considered as one diagnostic option in PTTM.

Contribution of Cell Block Obtained by Thoracentesis in the Diagnosis of Malignant Pleural Effusion

Aim

The aim of this study wass to compare the cytological features of pleural exudative fluids by conventional smear (CS) method and cell block (CB) method and also to assess the utility of the combined approach for cytodiagnosis of these effusions.

Materials and Methods

In all, 113 pleural exudative fluid samples were subjected to evaluation by both CS and CB methods over a period of 2 years. Cellularity, architecture patterns, morphological features, and yield for malignancy were compared, using the two methods. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for diagnosis of malignancy were calculated for both the methods, using histology as a gold standard.

Results

CB method provided higher cellularity, better architectural patterns, and additional yield for malignancy when compared with CS method. For 22 (40%) patients, histologic subtype was determined with CB especially for adenocarcinoma. The sensitivity, specificity, positive, and negative predictive values of cytology and CB were 48%, 100%, 100%, 67.8% and 59.2%, 100%, 100%, 72.8%, respectively.

Conclusion

CB technique definitively increased detection of malignancy in pleural fluid effusion when used as an adjunct to CSs. Also, CB provides material suitable for molecular genetic analysis for targeted therapies especially in the treatment of adenocarcinoma.

Conventional transbronchial needle aspiration is promising for identifying EGFR mutations in lung adenocarcinoma

Background

Conventional transbronchial needle aspiration (TBNA) is advantageous for the one‐step diagnosis and staging of lung adenocarcinoma under topical anesthesia and conscious sedation. We examined its efficacy for identifying EGFR mutations.

Methods

Forty‐seven patients with proven or suspected lung adenocarcinoma indicated for hilar‐mediastinal lymph node (LN) staging between June 2011 and December 2017 were enrolled. The cellblock was prepared using the plasma‐thrombin method. TaqMan PCR was used to detect mutations. Considering cost effectiveness, only the sample with the highest tumor cell fraction in the same patient was chosen for analysis.

Results

TBNA provided positive results of malignancy in 27 patients. Seventeen patients (63.0%) had cellblocks eligible for mutation testing. Bronchial biopsy (n = 6), neck LN fine needle aspiration (n = 1), and brushing (n = 1), provided higher tumor cell fractions for analysis in eight patients. TBNA was the exclusive method used in nine patients (19.1%). For patients with an inadequate TBNA cellblock, bronchial biopsy (n = 5), neck LN fine needle aspiration (n = 3), computed tomography‐guided transthoracic needle biopsy (n = 1), and brushing (n = 1) were used for analysis. Modification to specimen processing to prevent exhaustion by cytology after June 2016 improved the adequacy of cellblock samples (9/10, 90% vs. 8/17, 47.1%; P = 0.042).

Conclusions

These findings suggest the promising role of conventional TBNA and highlight the challenges of doing more with less in an era of precision medicine.

Management of cytological material, pre-analytical procedures and bio-banking in effusion cytopathology

Serous effusion fluid is one of the most commonly encountered specimens in routine cytopathology practice. It provides invaluable information about the patient and the clinical status; but to get the most of it, specimen handling and processing must be carried out properly. Cytomorphology is the basis of a successful analysis which should complemented by ancillary tests when needed. A wide spectrum of ancillary techniques - ranging from immunocytochemistry and flow cytometry to different assays of molecular pathology - can be applied to serous effusions. This article describes the acquisition and management of serous effusion fluids, methods for preservation and transportation, different techniques of cytopreparation, application of immunocytochemistry, flow cytometry, and fluorescence in-situ hybridization (FISH), as well as DNA extraction for polymerase chain reaction (PCR) and next generation sequencing (NGS). Principles of bio-banking of effusion samples are also discussed which is getting more important in correlation with the developments in personalized medicine.

A comparative study of conventional cytology and cell block method in the diagnosis of pleural effusion

Background

In a patient with pleural effusion, cytological study (CS) is one of the most useful investigations, especially when malignancy is suspected. Instead of applying only CS, the pleural fluid can be further processed using the cell block (CB) technique, which may augment the diagnostic utility. The aim of this study was to compare the diagnostic yields of CS, CB, and the combination of both, regardless of the etiology of pleural effusion.

Methods

A cross-sectional study was conducted on patients with pleural effusions who underwent thoracentesis from June 2015 to May 2016. All samples were submitted for routine biochemical analysis, CS, and CB histology. The results of cytopathological studies were compared to the final diagnoses.

Results

Out of a total of 353 samples, the final diagnoses included 278 (78.8%) malignancies, 41 (11.6%) infectious diseases, 16 (4.5%) other inflammatory diseases, and 18 (5.1%) transudative pleural effusions. CS and CB provided a similar diagnostic yield (48.7% vs. 49.9%, P=0.69), while the combination of both gave a higher yield (57.2%) (P<0.001, compared with CS). Among 278 malignant pleural effusions (MPE), the diagnostic yields of CS and CB were 61.2% and 61.9%, respectively. Combined CS and CB improved the diagnostic yield to 71.2% (P<0.001). However, both CS and CB had low diagnostic yields in infectious pleuritis, other inflammatory diseases, and transudative pleural effusions.

Conclusions

In MPE, CB provides a similar diagnostic performance to CS, while application of both techniques can significantly increase the diagnostic yield. However, in other pleural diseases, CB and CS had limited values in diagnosis.

Diagnosis of anaplastic lymphoma kinase rearrangement in cytological samples through a fluorescence in situ hybridization-based assay: Cytological smears versus cell blocks

Anaplastic lymphoma kinase (ALK) status analysis of lung cytological specimens should be successfully encouraged in routine practice because biopsy specimens are not always available. To date, the US Food and Drug Administration has approved both fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) as diagnostic tests for identifying ALK-positive patients eligible for treatment with crizotinib. Although ALK IHC is an optimal diagnostic tool, FISH becomes mandatory in equivocal cases. ALK FISH of paraffin-embedded tissue material is still the gold standard, whereas the cytological specimen assay has not yet been completely standardized. Many controversial data have been reported on the adequacy of cytology cell blocks (CBs) versus conventional smears for FISH testing. This review discusses some critical issues related to ALK FISH of cytological samples, including the triaging of collected specimens to optimize the material, the use of CBs versus conventional smears, and alternative methods for an ALK rearrangement diagnosis. Conventional smears have the advantages of an immediate evaluation, no probe tissue-related artifactual loss, no fixation-related alterations, and usually sufficient material for an analytic preparation. On the other hand, CBs have several advantages, including the appropriate conservation of the tissue architecture, an absence of problems related to cell overlapping, and the ability to evaluate neoplastic cells in a dark field. Cancer Cytopathol 2017;125:303-312. © 2017 American Cancer Society.

The Role of Liquid Based Cytology and Ancillary Techniques in the Peritoneal Washing Analysis: Our Institutional Experience

Background

The cytological analysis of peritoneal effusions serves as a diagnostic and prognostic aid for either primary or metastatic diseases. Among the different cytological preparations, liquid based cytology (LBC) represents a feasible and reliable method ensuring also the application of ancillary techniques (i.e immunocytochemistry-ICC and molecular testing).

Methods

We recorded 10348 LBC peritoneal effusions between January 2000 and December 2014. They were classified as non-diagnostic (ND), negative for malignancy-NM, atypical-suspicious for malignancy-SM and positive for malignancy-PM.

Results

The cytological diagnosis included 218 ND, 9.035 NM, 213 SM and 882 PM. A total of 8048 (7228 NM, 115SM, 705 PM) cases with histological follow-up were included. Our NM included 21 malignant and 7207 benign histological diagnoses. Our 820 SMs+PMs were diagnosed as 107 unknown malignancies (30SM and 77PM), 691 metastatic lesions (81SM and 610PM), 9 lymphomas (2SM and 7PM), 9 mesotheliomas (1SM and 8SM), 4 sarcomas (1SM and 3PM). Primary gynecological cancers contributed with 64% of the cases. We documented 97.4% sensitivity, 99.9% specificity, 98% diagnostic accuracy, 99.7% negative predictive value (NPV) and 99.7% positive predictive value (PPV). Furthermore, the morphological diagnoses were supported by either 173 conclusive ICC results or 50 molecular analyses. Specifically the molecular testing was performed for the EGFR and KRAS mutational analysis based on the previous or contemporary diagnoses of Non Small Cell Lung Cancer (NSCLC) and colon carcinomas. We identified 10 EGFR in NSCCL and 7 KRAS mutations on LBC stored material.

Conclusions

Peritoneal cytology is an adjunctive tool in the surgical management of tumors mostly gynecological cancers. LBC maximizes the application of ancillary techniques such as ICC and molecular analysis with feasible diagnostic and predictive yields also in controversial cases.

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.

[Value of Cell Block in the Diagnosis of Malignant Pleural Effusion]

背景与目的  恶性胸腔积液(malignant pleural effusion, MPE)是由原发于胸膜的恶性肿瘤或者是转移至胸膜的恶性肿瘤造成的胸腔积液。对于不明原因的单侧胸腔积液, 首要任务是排除或者是确诊恶性胸腔积液。胸腔积液沉淀物是将送检胸腔积液细胞学剩余的胸腔积液进行离心或者是自然静置所获得的细胞块。此技术具有操作简单、有创性小、重复性高、对恶性胸腔积液的诊断率相对较高等特点, 在恶性胸腔积液的诊断、治疗等方面起着重要的作用。本文主要从沉淀物的制作方法、免疫组织化学染色检查的鉴别诊断价值、沉淀物的诊断优势及沉淀物行基因检测的临床应用价值等方面来论述胸腔积液沉淀物对恶性胸腔积液的诊断价值。

The role of liquid-based cytology and ancillary techniques in pleural and pericardic effusions: an institutional experience

BACKGROUND

Fine-needle aspiration cytology (FNAC) of serous membrane effusions may fulfil a challenging role in the diagnostic analysis of both primary and metastatic disease. From this perspective, liquid-based cytology (LBC) represents a feasible and reliable method for empowering the performance of ancillary techniques (ie, immunocytochemistry and molecular testing) with high diagnostic accuracy.

METHODS

In total, 3171 LBC pleural and pericardic effusions were appraised between January 2000 and December 2013. They were classified as negative for malignancy (NM), suspicious for malignancy (SM), or positive for malignancy (PM).

RESULTS

The cytologic diagnoses included 2721 NM effusions (2505 pleural and 216 pericardic), 104 SM effusions (93 pleural and 11 pericardic), and 346 PM effusions (321 pleural and 25 pericardic). The malignant pleural series included 76 unknown malignancies (36 SM and 40 PM effusions), 174 metastatic lesions (85 SM and 89 PM effusions), 14 lymphomas (3 SM and 11 PM effusions), 16 mesotheliomas (5 SM and 11 SM effusions), and 3 myelomas (all SM effusions). The malignant pericardic category included 20 unknown malignancies (5 SM and 15 PM effusions), 15 metastatic lesions (1 SM and 14 PM effusions), and 1 lymphoma (1 PM effusion). There were 411 conclusive immunocytochemical analyses and 47 molecular analyses, and the authors documented 88% sensitivity, 100% specificity, 98% diagnostic accuracy, 98% negative predictive value, and 100% positive predictive value for FNAC.

CONCLUSIONS

FNAC represents a primary diagnostic tool for effusions and a reliable approach with which to determine the correct follow-up. Furthermore, LBC is useful for ancillary techniques, such as immunocytochemistry and molecular analysis, with feasible diagnostic and predictive utility.

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.

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.

The implementation of liquid-based cytology for lung and pleural-based diseases

OBJECTIVE

First introduced for the processing of cervico-vaginal samples, liquid-based cytology (LBC) soon found application in nongynecological specimens, including bronchoscopic brushings, washings and transcutaneous and transbronchial aspiration biopsy of the lung as well as pleural effusions. This article reviews the existing literature related to these specimens along with the authors' own experience.

STUDY DESIGN

A literature review was conducted through Ovid MEDLINE and PubMed search engines using several key words.

RESULTS

Most of the literature is based on data collected through the use of split samples. The data confirms that the use of LBC is an acceptable, and sometimes superior, alternative to the conventional preparations (CP). LBC offers several advantages, including the ability to transport in a stable collecting media, elimination of obscuring elements, ease of screening, excellent preservation, random representative sample, and application of ancillary techniques on additional preparations. Some diagnostic pitfalls related to the introduced artifacts were reported.

CONCLUSION

The utilization of LBC offers many advantages over CP and has a diagnostic accuracy that is equal to or surpasses that of CP. LBC affords a bridge to the future application of molecular and other ancillary techniques to cytology. Knowledge of the morphological artifacts is useful at the early stages of implementation.

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.

The cell block technique revisited for cells cultured in adherence and as "spheres"

A simple modification of the cell block technique for cultured cells grown in different conditions and suitable for the construction of tissue micro arrays (TMA) is described. The application of mechanical stirring during clot formation allows the uniform dispersion of cells in the fibrin mesh, thus increasing the final volume of the embedded material of evenly distributed cells. This technique is easily applied to spheres-obtained from cell lines cultured under appropriate conditions-that are enriched in stem cells. The possibility of constructing TMA using cell lines (grown in adherence and as spheres) and samples of the corresponding tumors or normal tissues may allow the direct comparison of original tumors with in vitro-expanded cell lines.