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

Diagnostic and Predictive Immunocytochemistry in Lung Cancer

BACKGROUND

Immunocytochemistry (ICC) is suitable for use on a range of cytology preparations, such as cell blocks, air-dried slides, ethanol-fixed slides, direct smears, cytospins, and liquid-based cytology (LBC) samples. However, it must be standardized against the gold standard of formalin-fixed paraffin-embedded tissues with adequate number of positive and negative controls. The role of ICC in lung cancer is crucial, as most lung cancer specimens are cytology samples. Accurate diagnosis and testing of certain biomarkers rely heavily on both diagnostic and predictive ICC.

SUMMARY

Key ICC markers important in lung cancer include, but are not limited to, diagnostic ICCs such as TTF-1, p40, Napsin A, and p63, as well as predictive ICCs like ALK, ROS-1, PD-L1, and NTRK.

KEY MESSAGES

With proper validation, immunocytochemistry for lung cancer can be effectively performed on direct smears, cytospins, and other specimens, even when resources for preparing cell blocks are unavailable. This is particularly true for diagnostic antibodies, but it is important to exercise caution with predictive ICC. Nonetheless, a low threshold for molecular testing should be maintained. PD-L1 ICC can be challenging and should ideally be performed on formalin-fixed cell blocks or biopsies when available.

A Comparative Study of Sodium Alginate and Plasma Thrombin Cell Block in Diagnostic Cytopathology

Background: Cell block is an indispensable supplement in the practice of cytopathology. The diagnostic utility of cytology specimens is significantly impacted by the capacity to generate sufficient cell blocks obtained from concentrated fluid samples or fine-needle aspiration specimens after routine processing. This routine processing involves getting directed passes to produce a cell block, especially if the cytopathologist believes additional immunocytochemical stains and/or molecular studies would be required. Objective: This study compared two methods of cell block preparation: the sodium alginate (SA) method and the plasma thrombin (PT) method. A comparison was made regarding overall cellularity, morphological preservation, and concealed artifacts. Methodology: This cross-sectional study evaluated 104 serous fluid samples and fine-needle aspirates. Cell blocks were prepared for each sample using the plasma thrombin and sodium alginate technique. The formalin-fixed, paraffin-embedded cell blocks were subjected to histochemical staining with hematoxylin and eosin, and slides were assessed for cellularity, artifacts, and morphological preservation. Results: The study utilized chi-square tests to analyze cellularity, morphology, and artifact presence, demonstrating significant differences in cellularity and artifacts between the two methods, with the sodium alginate method showing more cellularity and more artifacts, while morphologically, there was no significant difference between the two methods. Conclusion: Our study's findings have practical implications for cytopathologists. We conclude that, compared to plasma thrombin methodology, the sodium alginate cell block technique yields higher cellularity, while there was no difference in morphology. Even though artifacts were more prevalent in sodium alginate cell blocks than in plasma thrombin cell blocks, our study suggests that the former can be a better alternative for cell block examination.

The advent of the first electric driven EUS-guided 17 gauge core needle biopsy - A pilot study on subepithelial lesions

BACKGROUND AND AIMS

This pilot study aimed to evaluate safety and tissue sampling from subepithelial lesions (SEL) in the upper gastrointestinal tract with a novel electric motor driven endoscopic ultrasonography (EUS)-guided 17-gauge (G) size core needle biopsy (CNB) instrument.

METHODS

An investigator-led prospective open label, performance and safety control study, including seven patients (female n = 4, median 71 y, range 28-75) with a determined SEL (median size 30 mm, range 17-150 mm) in the upper digestive tract (stomach n = 6, duodenum n = 1) were eligible and later followed up 14 days after index procedure. All investigations were completed according to protocol with three FNB 22-G passes with four fanning strokes and two EndoDrill® 17-G passes with three fanning strokes.

RESULTS

Quality of samples as 'visible pieces' (>5 mm): FNB (n = 5/7) (fragmented/blood imbibed n = 1, poor tissue quantity n = 1) compared with 17-G CNB (n = 7/7). Histological result which led to final diagnosis (leiomyoma n = 2, adenocarcinoma n = 1, schwannoma n = 1, neuroendocrine tumour n = 1, desmoid tumour n = 1 and gastrointestinal stromal tumour (GIST) n = 1) could be obtained with the 17-G CNB instrument in all seven patients. FNB technique reached correct diagnosis in six patients. No serious adverse event were recorded.

CONCLUSIONS

By using an electric driven 17-G biopsy device, a true cylinder of core tissue can be obtained in one single puncture from the area of interest reducing the need for a second sampling. The absolute benefit of EUS-guided CNB is that the sample can be handled and histologically prepared in the same manner as standard percutaneous core needle sample, e.g., breast and prostate cancer.

Immunocytochemistry on frozen-embedded cell block for the diagnosis of hematolymphoid cytology specimen: a straightforward alternative to the conventional cell block

Agarose-based cell block (CB) technique can be modified to be combined with the frozen section technique for the preparation of a high-quality frozen-embedded CB (F-CB) from an effusion or fine-needle aspiration (FNA) cytology sample. This combined technique can be effectively used for the immunocharacterization of the hematolymphoid cells on F-CB. To demonstrate the applicability of performing diagnostic ICC on F-CB, we have analyzed the immunophenotype of the hematolymphoid cells in a series of eight cases of effusions and eight cases of FNA cytology specimens by using CB-ICC on sections cut from frozen-embedded CBs. The SurePathTM residue or cytologic material scraped off from the FNA cytology smear that was diagnostic for or suspicious of hematolymphoid malignancy was pelleted and pre-embedded in agarose. Half of the agarose-embedded pellet was frozen-embedded in OCT compound for the preparation of F-CB, while the other half was processed for the preparation of paraffin-embedded CB. Sections cut from the F-CB and P-CB were used for CB-ICC. Panels of ICC on the F-CBs could enable the immunocytochemical differential diagnosis of large cell hematologic malignancies that encompass anaplastic large cell lymphoma and other forms of large-cell hematolymphoid malignancies such as large B-cell lymphomas, anaplastic plasma cell myeloma, myeloid sarcoma, and T-lymphoblastic lymphoma. It also appeared that the small B-cell lymphomas in the effusions or FNAs could be differentially diagnosed with the aid of CB-ICC on the F-CB. A modified agarose-based CB technique can be combined with the frozen-embedded CB method for the preparation of F-CB that can be directly used for the immunocytochemical differential diagnosis of hematolymphoid cytology samples.

Contemporary art of cell-block preparation: Overview

Cell blocks (CBs) are paraffin-embedded versions of cytology specimens. These versions are contrasted with tissues made from surgical pathology specimens of formalin-fixed paraffin-embedded (FFPE) tissue. CBs enable various elective ancillary studies of a range of specimens. These studies include the potential to perform molecular tests with the enhanced cytopathological interpretation. CBs are increasingly reported in cytology specimens. The enhanced role of CBs incorporates additives with new markers for immunohistochemistry (IHC), including the multicolored approach to IHC, and the subtractive coordinate immunoreactivity pattern. Even when archived material is retrospectively retrieved, CBs are a major tissue source for many supplementary studies. The CBs have been qualitatively and quantitatively improved. CBs are significant since they have increased molecular markers standardized on FFPE tissue. High-quality CBs can serve as useful additions to cytological smear preparations and touch imprint cytology. Most cytological specimens, such as fine-needle aspirations, cavitary effusion, washings, brushings, and gynecological and non-gynecological liquid specimens, may be used to produce CBs. This review deals with the CB-making process and discusses various historical limitations with an emphasis on recent advances.

Optimal isolation of extracellular vesicles from pleural fluid and profiling of their microRNA cargo

Pleural effusion occurs in both benign and malignant pleural disease. In malignant pleural effusions, the diagnostic accuracy and sensitivity of pleural fluid cytology is less than perfect, particularly for the diagnosis of malignant pleural mesothelioma, but also in some cases for the diagnosis of metastatic pleural malignancy with primary cancer in the lung, breast or other sites. Extracellular vesicles (EVs) carry an enriched cargo of microRNAs (miRNAs) which are selectively packaged and differentially expressed in pleural disease states. To investigate the diagnostic potential of miRNA cargo in pleural fluid extracellular vesicles (PFEVs), we evaluated methods for isolating the extracellular vesicle (EV) fraction including combinations of ultracentrifugation, size-exclusion chromatography (SEC) and ultrafiltration (10 kDa filter unit). PFEVs were characterized by total and EV-associated protein, nanoparticle tracking analysis and visualisation by transmission electron microscopy. miRNA expression was analyzed by Nanostring nCounter® in separate EV fractions isolated from pleural fluid with or without additional RNA purification by ultrafiltration (3 kDa filter unit). Optimal PFEV yield, purity and miRNA expression were observed when PFEV were isolated from a larger volume of pleural fluid processed through combined ultracentrifugation and SEC techniques. Purification of total RNA by ultrafiltration further enhanced the detectability of PFEV miRNAs. This study demonstrates the feasibility of isolating PFEVs, and the potential to examine PFEV miRNA cargo using Nanostring technology to discover disease biomarkers.

Epigenomic analysis of formalin-fixed paraffin-embedded samples by CUT&Tag

For more than a century, formalin-fixed paraffin-embedded (FFPE) sample preparation has been the preferred method for long-term preservation of biological material. However, the use of FFPE samples for epigenomic studies has been difficult because of chromatin damage from long exposure to high concentrations of formaldehyde. Previously, we introduced Cleavage Under Targeted Accessible Chromatin (CUTAC), an antibody-targeted chromatin accessibility mapping protocol based on CUT&Tag. Here we show that simple modifications of our CUTAC protocol either in single tubes or directly on slides produce high-resolution maps of paused RNA Polymerase II at enhancers and promoters using FFPE samples. We find that transcriptional regulatory element differences produced by FFPE-CUTAC distinguish between mouse brain tumors and identify and map regulatory element markers with high confidence and precision, including microRNAs not detectable by RNA-seq. Our simple workflows make possible affordable epigenomic profiling of archived biological samples for biomarker identification, clinical applications and retrospective studies.

Application of international system for reporting serous fluid cytology (ISRSFC) in effusion samples-a prospective study in an oncology setting

INTRODUCTION

Serous fluid cytology is a cost-effective procedure that can help in the diagnosis, staging, and origin of the malignancy. Recently introduced International System for Reporting Serous Fluid Cytology (ISRSFC) standardizes the reporting of serous fluid cytology in the 5 categories: Category 1: Nondiagnostic (ND), Category 2: negative for malignancy (NFM), Category 3: atypia of undetermined significance (AUS), Category 4: suspicious for malignancy (SFM), and Category 5: malignant (MAL). Here, we present our experience adopting the ISRSFC.

MATERIALS AND METHODS

We implemented ISRSFC in December of 2019 at our institute and included a cohort of 555 prospective effusion samples. The pertinent surgical pathology, radiology, and clinical follow-up were also extracted to assess the risk of malignancy (ROM) and performance parameters.

RESULTS

The assessment of interobserver reliability indicated substantial concordance (κ = 0.717) between the 2 investigators for serous fluid categorization. A total of 555 effusion samples were classified as follows: ND, 14 (2.5%); NFM, 394 (71%); AUS, 12 (2.2%); SFM, 13 (2.3%); and MAL, 122 (22%). The ROM for the ND, NFM, AUS, SFM, and MAL categories was 57.1%, 9.9%, 66.7%, 66.7%, and 97.2%, respectively, in peritoneal effusions and 57.1%, 7.1%, 66.7%, 100%, 100%, respectively, in pleural effusions. The ROM for NFM and MAL was 0% and 100%, respectively, in pericardial effusion.

CONCLUSIONS

Application of the proposed ISRSFC can help in achieving uniformity and reproducibility in diagnoses and also help in risk stratification in cytology. ISRSFC was successfully adopted by our cytology laboratory and clinicians, with overall diagnostic performance similar to previous studies.

Cell block preparation as an adjunctive tool after fine-needle aspiration cytology for screening oral and maxillofacial diseases

OBJECTIVE

To describe the use of cell block (CB) preparation from fine-needle aspiration cytology for diagnosing oral and maxillofacial diseases.

STUDY DESIGN

We performed a retrospective analysis of 568 samples collected by our laboratory for CB preparation from fine-needle aspiration cytology of the oral and maxillofacial region between January 2001 and October 2021. We performed cytologic diagnoses and compared them with the available histopathologic diagnoses to calculate the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CB preparation for identifying malignant lesions.

RESULTS

The most frequent diagnosis was pleomorphic adenoma (n = 44, 7.7%), followed by metastatic squamous-cell carcinoma (n = 28, 4.9%) and odontogenic keratocyst (n = 26, 4.6%). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CB preparation, which revealed detailed morphologic and architectural patterns, were 70.0%, 100.0%, 100.0%, 62.5%, and 80.0%, respectively.

CONCLUSIONS

Cell block preparation from fine-needle aspiration cytology of the oral and maxillofacial region may be a useful adjunctive diagnostic tool for diagnosing oral and maxillofacial diseases because it reveals morphologic and architectural patterns similar to those shown on histopathologic slides, leading to the better categorization of diseases.

Application of Immunohistochemistry in Cytology

Immunohistochemistry (IHC), also referred to as immunocytochemistry in cytology literature, has revolutionized the practice of cytopathology. Because of the complexity of cytology preparation and limited diagnostic material, performing IHC remains a challenge. Formalin-fixed paraffin-embedded (FFPE) cell block (CB) is the optimal choice for IHC. In this review, the approaches for improving CB preparation will be discussed. When CB material is not available, various cytology specimens can also be used for IHC. With the utilization of Antigen Retrieval (AR) technique, these nonformalin-fixed cytology specimens can achieve successful IHC staining, comparable with the results from FFPE tissue sections. In the last part of this review, we will discuss the use of positive controls and the important role of AR in standardization of IHC in cytology.

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.

Characterization of an IDH1 R132H Rabbit Monoclonal Antibody, MRQ-67, and Its Applications in the Identification of Diffuse Gliomas

The current diagnosis of diffuse glioma involves isocitrate dehydrogenase (IDH) mutation testing. Most IDH mutant gliomas carry a G-to-A mutation at IDH1 position 395, resulting in the R132H mutant. R132H immunohistochemistry (IHC), therefore, is used to screen for the IDH1 mutation. In this study, the performance of MRQ-67, a recently generated IDH1 R132H antibody, was characterized in comparison with H09, a frequently used clone. Selective binding was demonstrated by an enzyme-linked immunosorbent assay for MRQ-67 to the R132H mutant, with an affinity higher than that for H09. By Western and dot immunoassays, MRQ-67 was found to bind specifically to the IDH1 R1322H, with a higher capacity than H09. IHC testing with MRQ-67 demonstrated a positive signal in most diffuse astrocytomas (16/22), oligodendrogliomas (9/15), and secondary glioblastomas tested (3/3), but not in primary glioblastomas (0/24). While both clones demonstrated a positive signal with similar patterns and equivalent intensities, H09 exhibited a background stain more frequently. DNA sequencing on 18 samples showed the R132H mutation in all IHC positive cases (5/5), but not in negative cases (0/13). These results demonstrate that MRQ-67 is a high-affinity antibody suitable for specific detection of the IDH1 R132H mutant by IHC and with less background as compared with H09.

The diagnostic value of add-on thyroid cell block in the evaluation of thyroid lesions

Objectives

Fine-needle aspiration (FNA) cytology plays a pivotal role in diagnosing thyroid nodules. Imaging assessment, followed by thyroid lesion sampling, is a widely applied clinical practice. Tissue fragments remnants are retrieved in cell-block providing an adjunct diagnostic tool for histopathology visualization and use of ancillary testing. This study aimed to evaluate whether the auxiliary application of cell-block adds to the diagnostic accuracy of the thyroid FNA.

Material and Methods

A total of 252 thyroid FNA cases between (2020 and 2021) were reviewed from patients aged 18-76. Of those, 150 cell-blocks were recovered and examined to assess their utility. Following categories were plotted during cell-blocks revision: (A) Inadequate material retrieved; (B) cell-block shows similar features along with their accompanying smears; and (C) value added to cytology diagnosis when using cell-block.

Results

The distribution of cell-blocks according to the aforementioned classification are as follows: A - non-diagnostic 63%, B - similar observation seen in both preparations 35%, and C - value added to the rendered diagnosis 2%. Hence, the use of cell-block improved cytology diagnosis in only 2% of total cases. Mostly were of immunostains application for diagnosis confirmation.

Conclusion

The non-diagnostic and atypical cytology cases have not been upgraded to a more meaningful category by the incorporation of cell-block performed with the routine non-enhancement random method. On the other hand, cell-blocks contributed generously toward immunostaining application in malignant scenarios.

Using American Type Culture Collection Cell Lines to Evaluate Interlaboratory Variables for Estrogen Receptor and Human Epidermal Growth Factor Receptor 2 Immunostaining

CONTEXT.—

Most laboratories currently use patient tissues for validating immunohistochemical stains.

OBJECTIVE.—

To explore advantages of using cell lines with known antigenicity as a validation method.

DESIGN.—

Five American Type Culture Collection (ATCC) cell lines with known negative, low positive, and moderate to strong estrogen receptor (ER) expression as well as negative, equivocal, and positive human epidermal growth factor receptor 2 (HER2) expression were cultured and made into cell blocks. One block from each cell line was fixed in formalin and another in ethanol before cell block preparation. Two sets of paired unstained slides from each block were sent to 10 different laboratories for HER2 and ER staining to be stained on runs from different days according to each laboratory's defined protocol.

RESULTS.—

The 10 study participants evaluated 40 slides in a blinded fashion. For ER expression, all 80 interpretations for the ER strong and moderate positive cell lines had the target ER-positive result, and 74 of 80 ER-negative cell lines (92.5%) had agreement with the intended negative result. The ER low positive cell line showed varied but positive expression among all observers. The HER2 (3+)-positive cell lines yielded a target interpretation of 3+ in 65 of 80 interpretations (81.2%). For the HER2-negative cell line 69 of 78 interpretations (88.5%) were consistent with the target response (0 or 1+). No significant variation was observed between the ethanol- and non-ethanol-exposed cell lines, or between runs by the same laboratory. Variation from target results clustered within laboratories.

CONCLUSIONS.—

This study indicates that variability between laboratories can be identified by using cell lines for quantitative or semiquantitative immunohistochemistry when using cultured cell lines of known antigenicity. These cell lines could potentially play a role in aiding anatomic pathology laboratories in validating immunohistochemistry tests for formalin- and ethanol-fixed tissues.

The basics of commonly used molecular techniques for diagnosis, and application of molecular testing in cytology

Molecular diagnostics has expanded to become the standard of care for a variety of solid tumor types. With limited diagnostic material, it is often desirable to use cytological preparations to provide rapid and accurate molecular results. This review covers important pre-analytic considerations and limitations, and a description of common techniques that the modern cytopathologist should understand when ordering and interpreting molecular tests in practice.

Recommendations for optimizing the use of cytology in the diagnosis and management of patients with lung cancer

Non-small cell lung cancer (NSCLC) is one of the oncological entities with the greatest evolution in molecular diagnosis due to the large number of diagnostic biomarkers and new treatments approved by international regulatory agencies. An accurate, early diagnosis using the least amount of tissue is the goal for the establishing and developing precision medicine for these patients. Rapid on-site evaluation (ROSE) provides cytological samples of optimal quantity and quality for a complete diagnosis of NSCLC. The usefulness of cytological samples has been demonstrated, not only for massive parallel sequencing but also for the quantification of the expression of programmed death-ligand 1 (PD-L1) and tumour mutational burden (TMB). Pre-analytical, analytical, and post-analytical recommendations are made for the management and appropriate use of cytological samples in order to obtain all the information necessary for the diagnosis and treatment of patients with NSCLC according to current quality parameters.

Malignant pleural effusion cell blocks are reliable resources for PD-L1 analysis in advanced lung adenocarcinomas: a concordance study with matched histologic samples

INTRODUCTION

In lung cancer patients presenting with malignant pleural effusion (MPE), cytology might represent the only source of tumor tissue for diagnosis and predictive biomarker testing. Programmed death ligand 1 (PD-L1) expression in tumor cells is a predictive biomarker for immunotherapy in non-small cell lung carcinomas and is tested using immunohistochemistry. However, knowledge of the validity of PD-L1 testing on MPE samples is limited. We evaluated the feasibility of immunocytochemistry (ICC) for PD-L1 in MPE cell blocks (CBs) and assessed the concordance in expression with patient-matched histologic samples.

MATERIALS AND METHODS

ICC for PD-L1 was performed on formalin-fixed paraffin-embedded CBs of MPE and patient-matched histologic samples, if available, using the automated Ventana PD-L1 SP263 assay. The tumor proportion score (TPS), based on partial or complete membranous tumor cell staining, was categorized as negative (<1%), low (≥1% to <50%), and high (≥50%). In CBs with any degree of PD-L1 expression, ICC for CD163 highlighting macrophages was performed to exclude nonspecific PD-L1 expression in macrophages. The CB PD-L1 TPS was compared with the TPS obtained from the patient-matched histologic samples.

RESULTS

Of 43 MPE CBs available, 25 were positive for PD-L1 (25 of 42; 59%), and 1 sample was inadequate. Of the 11 patient-matched histologic samples tested, the PD-L1 TPS categories were concordant for 10 of the 11 (91% concordance) cases.

CONCLUSIONS

PD-L1 expression in MPE CBs showed good concordance with expression in histologic samples and is feasible as a source for PD-L1 testing. The concurrent use of CD163 immunostains will aid in the manual assessment of PD-L1 TPS.

CelLock TM: an innovative standardized cell-block preparation procedure

The CelLock™ procedure kit is used to collect and prepare cellular specimens such as fine needle aspirates (FNA), cytology specimens, cultured cells, small tissue biopsies, and samples with scant tissue fragments or cells into a paraffin cell-block. This cell-block can be used for subsequent microtomy and staining using hematoxylin and eosin (H&E), special stains, immunohistochemistry (IHC), and applicable molecular techniques such as in situ hybridization (ISH). CelLock is a standardized method that provides optimal receipt, preservation, preparation, and processing of cell-blocks which, contain virtually all of the submitted specimens and are able to be embedded and sectioned in a reproducible fashion. The specimen contained within the cell-block is preserved such that all the cellular protein and genetic information is available for histological and ancillary testing.

Deconvolution Microscopy: A Platform for Rapid On-Site Evaluation (ROSE) of Fine Needle Aspiration (FNA) Specimens that Enables Recovery of the Sample

CONTEXT

Rapid on-site evaluation (ROSE) optimizes the performance of cytology, but requires skilled handling, and smearing can make the material unavailable for some ancillary tests. There is a need to facilitate ROSE without sacrificing part of the sample.

OBJECTIVE

We evaluated the image quality of inexpensive deconvolution fluorescence microscopy for optically sectioning non-smeared FNA tissue fragments.

DESIGN

A portion of residual material from 14 FNA samples was stained for 3 minutes in Hoechst 33342 and Sypro^TM Red to label DNA and protein respectively, transferred to an imaging chamber, and imaged at 200X or 400X magnification at 1 micron intervals using a GE DeltaVision inverted fluorescence microscope. A deconvolution algorithm was applied to remove out of plane signal, and resulting images were inverted and pseudocolored to resemble an H&E section. Five cytopathologists blindly diagnosed 2 to 4 representative image stacks per case (total 70 evaluations), and later compared them to conventional epifluorescent images.

RESULTS

Accurate definitive diagnoses were rendered in 45 of 70 (64%) total evaluations; equivocal diagnoses (atypical or suspicious) were made in 21 of 70 (30%). There were two false positive and two false negative "definite" diagnoses in three cases (4/70; 6%). Cytopathologists preferred deconvolved images compared to raw images (p< 0.01). The imaged fragments were recovered and prepared into a ThinPrep or cell block without discernable alteration.

CONCLUSIONS

Deconvolution improves image quality of FNA fragments compared to epifluorescence, often allowing definitive diagnosis while enabling the ROSE material to be subsequently triaged.

Feasibility of using digital confocal microscopy for cytopathological examination in clinical practice

Optical imaging modalities are emerging as digital microscopy tools for tissue examination. The investigation of these techniques for potential applications in anatomic pathology practice has focused primarily on surgical pathology and has not included cytopathological specimens. We evaluated the feasibility of using digital confocal microscopy (CM) to examine cytopathological specimens. Smears and cell suspensions collected in RPMI solution were prepared from tissue scrapes obtained from surgical resections of breast, lung, liver, and kidney. Air-dried smears and cell pellets obtained from centrifugation of the cell suspensions were stained with 0.6 mM acridine orange and imaged with a CM platform. After completion of imaging, the smears were stained with Diff-Quik (DQ), and cell pellets were routinely processed, embedded in paraffin wax, cut, and stained with hematoxylin and eosin (H&E). We evaluated the mean time to acquire digital CM images; quality of images based on the extent of tissue recognition (0%, grade 0; 1-19%, grade 1; 20-50%, grade 2; >50%, grade 3); comparison of images with DQ- and H&E-stained specimens; and ability to make specific diagnoses. We imaged 91 smears and 52 cell pellets and acquired digital CM images within 2-3 min, with 92% and 88% of images, respectively, from smears and cell pellets showing grade 3 quality. On the basis of CM images, 8 smears (9%) and 7 cell pellets (14%) were categorized as benign, and 83 (91%) and 45 (88%), respectively, as malignant. Specific diagnoses were made by using digital CM images of smears and cell pellets that matched accurately with corresponding DQ- and H&E-stained preparations. The results of our first feasibility study clearly indicated the utility of CM as a next-generation digital microscopy tool for evaluating cytology specimens. Prospective clinical studies are warranted for validating our findings for potential incorporation into cytopathological clinical practice.

Sodium Alginate versus Plasma Thrombin Cell Blocks in Diagnostic Cytopathology: A Comparative Analysis

BACKGROUND

Cell blocks (CBs) are an essential adjunct in cytopathology practice. The aim of this study was to compare 2 techniques of CB preparation - plasma thrombin (PT) method with sodium alginate (SA) method for overall cellularity, morphological preservation, obscuring artefacts, immunocytochemistry (ICC), suitability for molecular analysis, and cost of preparation.

DESIGN

A total of 80 fine-needle aspirates from various sites and serous effusion samples were included. Of these cases, by random selection, 40 each were prepared by PT method and SA methods, respectively. The haematoxylin-eosin-stained sections from the formalin-fixed, paraffin-embedded CBs from both methods were evaluated in a blinded fashion by 2 cytopathologists and scored for cellularity, artefacts, and morphological preservation and analysed by χ2 test with Yates correction. We evaluated 6 cases from each method by ICC for a range of membrane, cytoplasmic and nuclear marker expression. DNA was extracted from four cases to evaluate their utility for molecular analysis.

RESULTS

CB sections from PT and SA techniques showed comparable cellularity and excellent cytomorphological preservation. Blue gel-like artefacts were common in the SA technique but did not interfere with morphological evaluation. ICC staining results were also similar. DNA yield and utility for PCR were also comparable. The SA-CB cost half that of PT-CB (USD 0.4 vs. USD 1).

CONCLUSION

SA technique of CB preparation is an excellent low-cost alternative to PT method for CB preparation.

The Contributory Role of Cell Blocks in Salivary Gland Neoplasms Fine Needle Aspirations Classified by the Milan System for Reporting Salivary Gland Cytology

(1) Background: The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) was introduced in 2018, bringing an organ-specific classification system for salivary gland cytopathology. The aim of present study is to evaluate the MSRSGC prospectively, based on a two-year experience in the tertiary care center pathology department, and evaluate the role of routine cell block (CB) preparation in salivary gland cytopathological diagnostics. (2) Methods: In our institution, the Department of Pathology, Fimlab Laboratories, Tampere, Finland, the MSRSGC has been implemented in salivary gland cytopathology since January 2018 and, over a two-year period (January 2018–December 2019), there were 365 fine-needle aspirations, of which 164 had a surgical follow-up. The CB methods used were Plasma-thrombin, the collection of visible fragments, and the Shandon and in-house methods. (3) Results: The MSRSGC diagnostic figures were as follows: accuracy 87.5%, sensitivity 45.8% and specificity 98.9%. For diagnostic categories of MSRSGC (non-neoplastic, benign neoplasm and malignant neoplasm) (n = 63) diagnostic accuracy was 98.4%, and for undetermined categories (atypia of undetermined significance, salivary gland neoplasm of uncertain malignant potential and suspicious for malignancy) (n = 49) diagnostic accuracy was 73.5%. Non-contributory cell blocks resulted more often in a false negative diagnosis (25%, 3/12) than a true negative diagnosis (10%, 7/73, p < 0.001), and is, most likely, an insufficient cytological diagnosis (86%, 18/21, p < 0.001). (4) Conclusion: The application of MSRSGC and CBs are beneficial in salivary gland cytological diagnosis, increasing diagnostic accuracy and, thus, patients’ management and treatment.

Utility of cell block as an adjunct to liquid-based cytology for diagnosing papillary thyroid carcinoma

Background

Although liquid-based cytology (LBC) has gained popularity among clinical laboratories, it is unclear whether it is equivalent to conventional smears for making a definite diagnosis of papillary thyroid carcinoma (PTC). The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) suggests a definite diagnosis of PTC is preferred when there are at least one of three features (papillary architecture, psammomatous calcifications, and frequent pseudonuclear inclusions) plus other typical cytomorphological findings. This study evaluated whether an additional cell block (CB), prepared from the residual LBC material, could help improve the diagnosis of PTC.

Materials and Methods

A total of 62 cases with both ThinPrep LBC and CB preparations and histopathological follow-up of PTC were retrieved between November 2016 and March 2019. The ThinPrep LBC and CB slides were reviewed separately to identify any papillary architecture, psammomatous calcifications, or pseudonuclear inclusions for diagnosing PTC.

Results

Among the 51 cases with cytological diagnosis of PTC in the LBC+CB slides, the CB provided additional diagnostic information in 15 cases, which were initially diagnosed as suspicious for PTC based on the LBC slides alone. This information included papillary architecture (n=11), psammomatous calcification (n=1) and pseudonuclear inclusions (n=5). The number of specimens in the 51 cases containing at least one of the three features increased from 42 (LBC) to 51 (LBC+CB). The accuracy for diagnosing PTC increased from 58.1% for LBC alone to 82.3% for the LBC+CB examination.

Conclusion

An adjunctive CB preparation may improve the LBC technique for diagnosing PTC.

Cell Block and Its Impact in the Diagnosis of Jaw Lesions over Fine Needle Aspiration Cytology

OBJECTIVES

To determine the role and efficacy of fine needle aspiration cytology (FNAC) and cell block in diagnosis of jaw lesions and compare the agreement between FNAC and cell block to predict the diagnosis.

METHOD

The sample comprised 51 cases, including 12 odontogenic keratocysts (OKCs), 8 ameloblastomas, 22 radicular cysts, 7 dentigerous cysts, and 1 each of intraosseous mucoepidermoid carcinoma (MEC) and adenomatoid odontogenic tumor (AOT). FNAC samples remaining after hematoxylin and eosin (H&amp;E)-stained cytosmear diagnosis were centrifuged at 3,000 rpm for 10 min. The supernatant was discarded and sediment mixed with 2-3 mL alcohol and filtered. To this, 10% formalin was added, filtered, taken for routine processing, and stained with H&amp;E. The result of FNAC smear and cell block was compared with histopathological diagnosis.

RESULTS

On cytological examination of the smears, 7 OKCs and 22 radicular cysts were diagnosed, whereas ameloblastomas, AOT, intraosseous MEC, and dentigerous cysts were not. This gave an agreement of 56.8% with the biopsy reports. Cell block sections stained with H&amp;E of 12 OKCs, 22 radicular cysts, 1 MEC, and 3 cases of ameloblastoma offered a diagnosis in accordance with the biopsies giving an agreement of 74.5%, while dentigerous cyst and AOT failed to do so. In comparison with FNAC, additionally 5 cases of OKC and 1 of MEC could be detected, and in ameloblastoma, out of 8 cases, only 3 yielded a concordant diagnosis through the cell block technique.

CONCLUSION

In comparison with FNAC, the architectural pattern and the morphology of the cells were better preserved by the cell block technique. This substantiates that cell block could be used as an ancillary technique to aid in definitive diagnosis of head and neck swellings.

Image-guided lymph node fine-needle aspiration: the Johns Hopkins Hospital experience

INTRODUCTION

Although the diagnostic utility of lymph node fine-needle aspiration (FNA) is well established in the evaluation of metastatic malignancy, its value in the diagnosis of lymphoma is more controversial; yet, there is a growing trend among practitioners towards less-invasive procedures such as FNA and core needle biopsy (CNB). The guidelines recently published by the American Society for Clinical Pathology/College of American Pathology (CAP) regarding the workup of lymphoma include recommendations on the value and limitations of FNA.

MATERIALS AND METHODS

We reviewed 1237 image-guided lymph node aspirates from 695 procedures (410 nodes from 360 ultrasound [US]-guided cases, 799 from 309 endobronchial ultrasound [EBUS], 25 from 23 endoscopic ultrasound [EUS], and 3 from 3 computed tomography [CT]).

RESULTS

The majority (40 of 46, 87%) of lymph nodes suspected of lymphomatous involvement were aspirated under ultrasound. Core needle biopsy [CNB] was obtained for 41 (89%) lymph nodes, including all 40 US specimens. Flow cytometry (FC) was performed on 37 (80%) aspirates; aspirates without FC were from patients who had a history of Hodgkin lymphoma, or showed granulomata or non-hematologic malignancy onsite. Thirty-one (67%) lymph nodes were sent for review by hematopathology. Forty-two (91%) lymph node FNA/CNB yielded actionable diagnoses. Seventeen of 241(7%) cases aspirated for other indications (14 US, 3 EBUS) were involved by a lymphoproliferative process. All were reviewed by hematopathology. All 14 US cases had FC and CNB.

CONCLUSION

Our institutional approach towards lymph node cytopathology for lymphoma workup appears to be in accordance with the new CAP guidelines, and demonstrates a potential triage and workflow model for lymph node FNA specimens that allows for accurate diagnosis in cases where lymphoma is a consideration.

The Role of Cell Blocks and Immunohistochemistry in Thyroid Atypia of Undetermined Significance/Follicular Lesion of Undetermined Significance Bethesda Category

INTRODUCTION

Thyroid cytology is a widely accepted tool in the clinical triaging of nodular lesions. Cell blocks (CBs) can help in the diagnosis of atypical lesions, namely, thyroid Bethesda category of Atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS).

METHODS

In a series of 224 AUS/FLUS thyroid samples with CB, we studied CB cellularity and feasibility of 3 immunohistochemical markers (cytokeratin 19 [CK19], HBME-1, and galectin-3) apart and in combination.

RESULTS

The CBs were non-diagnostic in 34 cases. Twenty-four CBs contained <10 cells, 45 CBs 10-50 cells, and 121 CBs >50 cells. Notably, more cellularity was found in CBs performed by plasma-thrombin and in-house techniques (p < 0.001). The diagnostic accuracy to detect malignancy was 65.1% for CK19, 72.1% for HBME-1, and 70.3% for galectin-3.

CONCLUSION

In conclusion, CB cellularity is essential for successful immunohistochemistry application and further diagnostic workup of AUS/FLUS cases.

The Usefulness of 4 Immunoperoxidase Stains Applied to Urinary Cytology Samples in the Pathologic Stage of Urothelial Carcinoma: A Study With Histologic Correlation

BACKGROUND

Currently, the golden rule for the diagnosis of urothelial carcinoma is biopsy and cystoscopy, unfortionally both are costly, invasive, and uncomfortable. While most urothelial cancers are noninvasive at presentation, it is necessary to find a highly sensitive, noninvasive way to diagnose in its earlier stages, Cytology with immunostaining is a noninvasive, reliable method that might play a role in detecting the earlier stages before its progression and accurate correlation with different stages of these tumors.

AIM

This study aimed to reach an accurate level in the staging of urothelial carcinoma using CD44, ProExC, Laminin, and Fascin on urinary cytology.

DESIGN

We include a total of 180 urinary cytology specimens with their surgical biopsies' counterparts, the staging of the surgical specimens were done according to AJCC2017TNM classification, while their counterpart urinary samples were centrifuged and the sediment was used for H&E and immunocytochemical staining with CD44, ProExC, Laminin, and Fascin.

RESULTS

The diagnosis of Ta-stage tumors was done according to the following immunohistochemical (IHC) profile [positive (+ve) CD44, negative (-ve) proExC, -ve Laminin, and -ve Fascin] with 100% sensitivity, 100% specificity. The diagnosis of Tis stage tumors was done according to IHC profile [-ve CD44, +ve proExC, -ve Laminin, and -ve Fascin] with 100% sensitivity, 93% specificity. The diagnosis of T1 stage tumors according to IHC profile [-ve CD44, +ve proExC, +ve Laminin, and -ve Fascin] with 100% sensitivity, 97% specificity, The diagnosis of T2 and T3 stage tumors was done according to IHC profile [-ve CD44, +ve proExC, +ve Laminin and weak to moderate +ve Fascin] with 100% sensitivity, 92% specificity, while the diagnosis of T4 stage tumors according to the IHC profile [-ve CD44, +ve proExC, +ve Laminin, and intense +ve Fascin] with 100% sensitivity, 100% specificity.

CONCLUSION

Using (CD44, ProExC, Laminin, and Fascin) on urinary cytology is a simple, reliable, and noninvasive method for the staging of urothelial carcinoma with 99% total accuracy.

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.

Practical diagnostic utility of thyroid fine-needle aspiration cell blocks: is always too much?

INTRODUCTION

Thyroid fine-needle aspiration (tFNA) is a powerful screening tool for assessing solitary thyroid nodules. Generally, morphologic evaluation of smears yields an accurate diagnosis; but, in some cases it is useful to have a cell block (CB) to conduct ancillary studies such as immunohistochemistry (IHC). Cytologic diagnoses guide clinical decisions, so it is important that accurate and efficient diagnoses be rendered. Our study evaluates the diagnostic utility of the CB in the evaluation of tFNAs.

MATERIALS AND METHODS

We performed a retrospective chart review of all tFNA specimens from January 2014 to July 2019. Data collected included TAT (in days), diagnosis, if a CB was prepared, and if it was diagnostically contributory. Descriptive statistics were calculated. Data were analyzed using the χ² test and the Mann-Whitney U-test.

RESULTS

Of the 2321 specimens, 40.2% (933) had CB and only 0.3% (7) were diagnostically contributory. IHC was used for 2 cases. For cases with CB, the median TAT was one day [0-18 days] and the median TAT without CB was 0 [0-9 days]. There was a significant difference in TAT between cases with a CB and those without. Most cases without a CB had same-day TAT (66.4%), whereas only 1.1% of those with a CB had same day TAT. Cases with CB were more likely to have a TAT >1 day (65% versus 12.1%) or >3 days (25.4% versus 10%) than those without a CB (P < 0.0001).

CONCLUSIONS

We found the diagnostic utility of CB for tFNAs to be very low. The addition of a CB added at least 1 day to the TAT in all diagnostic strata. The additional time causes patients to wait for results, even for nondiagnostic studies. The increased TAT, resources, and manpower use may be reduced if CB were produced only as needed-if the results of the smear were ambiguous or if ancillary tests were needed to confirm the diagnosis.

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.

Lung cancer cytology and small biopsy specimens: diagnosis, predictive biomarker testing, acquisition, triage, and management

In the 21st century, there has been a dramatic shift in the management of advanced-stage lung carcinoma, and this has coincided with an increasing use of minimally invasive tissue acquisition methods. Both have had significant downstream effects on cytology and small biopsy specimens. Current treatments require morphologic, immunohistochemical, and/or genotypical subtyping of non-small cell lung carcinoma. To meet these objectives, standardized classification of cytology and small specimen diagnoses, immunohistochemical algorithms, and predictive biomarker testing guidelines have been developed. This review provides an overview of current classification, biomarker testing, methods of small specimen acquisition and triage, clinical management strategies, and emerging technologies.

Preanalytic variables in quality and quantity of nucleic acids extracted from FNA specimens of thyroid gland nodules collected in CytoLyt: Cellularity and storage time

BACKGROUND

Morphologic and genetic analysis of thyroid nodules may be performed from a single vial. Preanalytic variables that affect nucleic acid extracted from a single vial are evaluated.

METHODS

Thyroid fine-needle aspiration (FNA) specimens collected in CytoLyt were evaluated. A ThinPrep slide was prepared. Extracted nucleic acids were analyzed using Oncomine Comprehensive Panel, version 2, after Ion AmpliSeq library preparation. A pathologist and a cytotechnologist enumerated specimen cellularity.

RESULTS

Fifty-six samples were collected from 55 nodules in 53 patients. Bethesda category correlated with cellularity (P = .01), and storage time (median, 43 days; range, 7-77 days) was longer for specimens in categories II and III than for those in categories IV and VI (P = .01). The mean specimen DNA concentration was 4.5 ng/µL (range, 0-23.8 ng/µL), and 25 (45%) had concentrations >3.3 ng/µL. The mean specimen RNA concentration was 4.8 ng/µL (range, 0-42.4 ng/µL), and 31 (55%) had concentrations >1.4 ng/µL. Nucleic acid quantity increased with epithelial cellularity. Storage time weakly correlated with the quantity of extracted DNA, independent of cellularity, but not extracted RNA. Greater proportions of cell-free DNA and lesser proportions of long, intact RNA fragments were extracted from a subset of samples with longer storage time. Among 15 single nucleotide variants, the median mutant allelic fraction was 15.1%. One false-negative result was identified. Five specimens subsequently determined to harbor a genetic alteration failed quality metrics.

CONCLUSIONS

Cellularity and storage time affect the quantity and quality of nucleic acid extracted from thyroid FNA specimens collected in CytoLyt. Further investigation will serve to quantify the magnitude of such effects and to elucidate other contributing factors.

Tumor Cell Representation by an Improvised Technique of Fine-Needle Aspiration Specimen Acquisition and Cell Block Preparation: Our Experience in Lung Cancer Cases in a Peripheral Center of Eastern India

Background

Being a minimally invasive diagnostic technique, Fine-Needle Aspiration Cytology (FNAC) has become the first-line test and corresponding aspirated material has become the target specimen for diagnosis and ancillary tests in lung carcinoma. Although the role of Cell Blocks (CBs) in diagnosis and in ancillary testing is well recognized in literature, limited attention has been paid to specimen procurement and triage in the preparation of CBs. In the present scenario, CBs are not consistently optimal because of its low cellularity.

Aims

This study is aimed to describe an improvised technique of specimen acquisition and cell block preparation in CT-guided FNACs of lung carcinoma cases in a resource-constrained center and to assess its efficacy for optimal representation of cellularity, morphology, and architecture.

Materials and Methods

Total 85 lung carcinoma cases undergoing CT-guided FNAC in our center from February 2017 to January 2018 were included in this study. 4 to 5 direct smears and subsequent CBs were made from material obtained by single pass. Cellularity of smears and corresponding cell blocks were assessed and categorized according to a scoring system (score 1 to 3 for number of cells <50, 50-100, >100, respectively). Preserved architecture and morphology were also assessed in smears and CBs.

Results

The evaluated samples showed a cellularity score 3 in 65.4%CBs and score 2 in 24.7% CBs. Overall, 90.1% cell blocks had acceptable cellularity. Cell morphology was preserved in all CBs of acceptable cellularity, except for two adenocarcinoma, one squamous cell carcinoma, and one small cell carcinoma blocks. Cellular architecture was also preserved in all CBs of acceptable cellularity.

Conclusions

This simple improvised technique of CB preparation optimized its cellularity, morphology, and architectural preservation, even after adequate cellular FNA smears.

Diagnosis and treatment of early and locally advanced non-small-cell lung cancer: The 2019 AIOM (Italian Association of Medical Oncology) clinical practice guidelines

The Italian Association of Medical Oncology (AIOM) has developed clinical practice guidelines for the diagnosis and treatment of patients with early and locally advanced non-small cell lung cancer. In the current paper a panel of AIOM experts in the field of thoracic malignancies discussed these topics, analyzing available scientific evidences, with the final aim of providing a summary of clinical recommendations, which may guide physicians in their current practice.

The growth of non-solid neoplastic lung nodules is associated with low PD L1 expression, irrespective of sampling technique

Background

Few data are known regarding the molecular features and patterns of growth and presentation which characterize those lung neoplastic lesions presenting as non-solid nodules (NSN).

Methods

We retrospectively reviewed two different cohorts of NSNs detected by CT scan which, after transthoracic fine-needle aspiration (FNA) and core needle biopsy (CNB) received a final diagnosis of malignancy. All the enrolled patients were then addressed to surgical removal of lung cancer nodules or to exclusive radiotherapy. Exhaustive clinical and radiological features were available for each case.

Results

In all 62 analysed cases the diagnosis of adenocarcinoma (ADC) was reached. In cytologic samples, EGFR activating mutations were identified in 2 of the 28 cases (7%); no case showed ALK/EML4 or ROS1 translocations. In the histologic samples EGFR activating mutation were found in 4 out of 25 cases (16%). PD-L1 immunostains could be evaluated in 30 cytologic samples, while the remaining 7 did not reach the cellularity threshold for evaluation. TPS was < 1% in 26 cases,  > 1% < 50% in 3, and > 50% in 1. All surgical samples showed TPS < 1%. Of the 17 cases that could be evaluated on both samples, 15 were concordantly TPS 0, and 2 showed TPS > 1% < 50 on the biopsy samples. TPS was < 1% in 14 cases, > 1%/< 5% in 4 cases, > 5%/< 50% in 2 cases, > 50% in 1 case.

Conclusions

Overall PD-L1 immunostaining documented the predominance of low/negative TPS, with high concordance in FNA and corresponding surgical samples. It can be hypothesized that lung ADC with NSN pattern and predominant in situ (i.e. lepidic) components represent the first steps in tumor progression, which have not yet triggered immune response, and/or have not accumulated a significant rate of mutations and neoantigen production, or that they belong to the infiltrated-excluded category of tumors. The negative prediction of response to immunomodulating therapy underlines the importance of rapid surgical treatment of these lesions. Notably, cell block cytology seems to fail in detecting EGFR mutations, thus suggesting that this kind of sampling technique should be not adequate in case of DNA direct sequencing.

Treatment of advanced non-small-cell lung cancer: The 2019 AIOM (Italian Association of Medical Oncology) clinical practice guidelines

The Italian Association of Medical Oncology (AIOM) has developed clinical practice guidelines for the treatment of patients with advanced non-small cell lung cancer (NSCLC). In the current paper a panel of AIOM experts in the field of thoracic malignancies discussed the available scientific evidences, with the final aim of providing a summary of clinical recommendations, which may guide physicians in their current practice.

Neuroendocrine carcinomas: Cytological mimics and diagnostic dilemmas

BACKGROUND

Neuroendocrine carcinomas (NEC) are rare tumours with multiple morphologic mimics. The cytologist may miss these cases if not aware.

AIMS AND OBJECTS

We focused upon the clinical presentation, cytological features and problems in the diagnosis of NEC.

MATERIALS AND METHODS

We studied the detailed cytomorphology of 19 cases of NEC (histopathology proved).

RESULTS

Of these 19 cases of NEC, 15 cases constituted fine needle aspiration (FNA) specimens, one transbronchial needle aspiration specimen, two pleural fluid specimens and a single biliary brushing specimen. All of the FNA specimens were from extra-pulmonary sites (namely, breast, pancreas, liver and three lymph node FNAs). Eight of the 19 cases (42.1%) showed a significant disparity between cytological and histopathology diagnoses. The break-up of discordant diagnoses are of adenocarcinoma (three cases), Ewing's sarcoma (one case), infiltrating ductal carcinoma (one case), lymphoma (one case), and squamous cell carcinoma (two cases). The cytology of NECs predominantly showed discrete, round to oval cells with a moderate amount of cytoplasm. The nuclei were pleomorphic, having prominent nucleoli. Occasional cases showed characteristic salt and pepper chromatin and were correctly diagnosed as a neuroendocrine group of tumours.

CONCLUSION

The accurate diagnosis of NEC depends on clinical correlation, meticulous screening for any obvious neuroendocrine features and cell block morphology. Immunohistochemistry is essential for ruling out of tumours of neuroendocrine origin. A Ki67 index is mandatory for grading of all neuroendocrine tumours.

Mycobacterium tuberculosis diagnosed promptly by bronchial brushing cytology in an immunocompetent patient

Respiratory cytology plays an important role in the diagnosis of lower respiratory tract infection. The timely diagnosis of pulmonary tuberculosis (TB) can be very challenging due to the nonspecific cytomorphologic features and limited number of organisms, especially in the immunocompetent patients. Here, we reported a case of TB diagnosed promptly by bronchial brushing cytology in a 51-year-old immunocompetent patient. She presented with a 4 cm fungating lesion involving right lower lobe of the lung and mediastinal lymphadenopathy with an initial concern for malignancy. Bronchial brushing showed scattered acute inflammatory cells in the background of necrosis. A cell block was prepared and acid-fast bacilli (AFB)-positive organisms were identified. Subsequent polymerase chain reaction (PCR) performed on the sputum detected Mycobacterium tuberculosis. This case highlights the importance of recognizing the cytomorphology of TB from a bronchial brushing specimen; and also emphasizes the potential utility of the cell block from respiratory cytology in the diagnosis of TB.

Targeted deep sequencing of cell-free DNA in serous body cavity fluids with malignant, suspicious, and benign cytology

BACKGROUND

Liquid biopsy using cell-free DNA (cfDNA) presents new opportunities for solid tumor genotyping. While studies have demonstrated the utility of cfDNA from plasma, cfDNA from other body fluids remains underexplored.

METHODS

We evaluated the molecular features and clinicopathologic correlates of cfDNA from serous body cavity fluids by performing hybrid capture-based next-generation sequencing (NGS) on cfDNA isolated from residual effusion supernatants. Twenty-one serous effusions from pleural (n = 15), peritoneal (n = 5), and pericardial (n = 1) cavity were analyzed.

RESULTS

The supernatants provided a median cfDNA concentration of 10.3 ng/µL. Notably, all effusions were sequenced successfully to a median depth >1000×, revealing a broad range of genetic alterations including single nucleotide variants, small insertions and deletions, amplifications, and fusions. Specifically, pathogenic alterations were identified in all malignant fluids (13/13), all fluids suspicious for malignancy (2/2), and 1 benign fluid (1/6) from a patient with metastatic cancer. To validate our findings, we examined matching results from 11 patients who underwent additional testing using formalin-fixed, paraffin-embedded (FFPE) specimens. In 8 patients, the paired results between FFPE and supernatant testing were concordant, whereas in the remaining 3 patients, supernatant analysis identified additional variants likely associated with resistance to targeted therapies. Additional comparison between FFPE and supernatant testing showed no difference in DNA concentration (P = .5), depth of coverage (P = .6), or allele frequency of pathogenic mutations (P = .7).

CONCLUSION

cfDNA isolated from serous body cavity fluids represents a promising source of genomic input for targeted NGS.

Australian consensus statement for best practice ROS1 testing in advanced non-small cell lung cancer

Lung cancer is the most commonly diagnosed malignancy and the leading cause of death from cancer globally. Diagnosis of advanced non-small cell lung cancer (NSCLC) is associated with 5-year relative survival of 3.2%. ROS proto-oncogene 1 (ROS1) is an oncogenic driver of NSCLC occurring in up to 2% of cases and commonly associated with younger age and a history of never or light smoking. Results of an early trial with the tyrosine kinase inhibitor (TKI) crizotinib that inhibits tumours that harbour ROS1 rearrangements have shown an objective response rate (ORR) of 72% (95% CI 58-83%), median progression free survival (PFS) of 19.3 months (95% CI 15.2-39.1 months) and median overall survival (OS) of 51.4 months (95% CI 29.3 months to not reached). Therefore, with the availability of highly effective ROS1-targeted TKI therapy, upfront molecular testing for ROS1 status alongside EGFR and ALK testing is recommended for all patients with NSCLC. We review the tissue requirements for ROS1 testing by immunohistochemistry (IHC) and fluorescent in situ hybridisation (FISH) and we present a testing algorithm for advanced NSCLC and consider how the future of pathology testing for ROS1 may evolve.

Diagnostic utility of cell block in fine needle aspiration cytology of thyroid gland

BACKGROUND

This study was conducted to evaluate the diagnostic utility of cell block material in fine needle aspiration (FNA) of thyroid nodules.

DESIGN

A total of 242 thyroid fine need aspirations (FNAs) were performed between January 2015 and December 2015. Of those, all consecutive thyroid FNA cases with cell blocks (n = 140) from 129 patients (age: 58.9 ± 12.8 years) are included in this study. Cytology slides and cell blocks are reviewed for adequacy assessment based on the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) and then categorizing them into TBSRTC diagnostic categories. These cases are divided into two groups, combined cytology and cell block (C + CB) and cytology without cell block (C).

RESULTS

In the first group (C + CB), a total 140 cases are categorized in TBSRTC as follows: I: 13 (9.3%) cases, II: 78 (55.7%) cases, III: 7 (5%), IV: 16 (11.4%), V: 3(2.2%) and VI: 23 (16.4%). In the second group (C), the cases are classified in TBSRTC as follows: I: 23 (16.4%) cases, II: 70 (50%), III: 7 (5%), IV: 16 (11.4%), V: 3 (2.2%) and VI: 21 (15%). Nondiagnostic rate was 7.1% lower in the first group (C + CB) as compared with second group (C) (First group: 9.3% vs second group: 16.4%, P = .0764).

CONCLUSIONS

Combined use of cytology slides and cell block decreases the nondiagnostic rate up to 7.1% as compared with cytology without cell block.

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.

Needle Biopsy Adequacy in the Era of Precision Medicine and Value-Based Health Care

CONTEXT.—

Needle biopsy of diseased tissue is an essential diagnostic tool that is becoming even more important as precision medicine develops. However, the capability of this modality to efficiently provide samples adequate for diagnostic and prognostic analysis remains quite limited relative to current diagnostic needs. For physicians and patients, inadequate biopsy frequently leads to diagnostic delay, procedure duplication, or insufficient information about tumor biology leading to delay in treatment; for health systems, this results in substantial incremental costs and inefficient use of scarce specialized diagnostic resources.

OBJECTIVE.—

To review current needle biopsy technology, devices, and practice with a perspective to identify current limitations and opportunities for improvement in the context of advancing precision medicine.

DATA SOURCES.—

PubMed searches of fine-needle aspiration and core needle biopsy devices and similar technologies were made generally, by tissue site, and by adequacy as well as by health economics of these technologies.

CONCLUSIONS.—

Needle biopsy adequacy can be improved by recognizing the importance of this diagnostic tool by promoting common criteria for needle biopsy adequacy; by optimizing needle biopsy procedural technique, technologies, clinical practice, professional education, and quality assurance; and by bundling biopsy procedure costs with downstream diagnostic modalities to provide better accountability and incentives to improve the diagnostic process.

Ancillary Techniques in Cytologic Specimens Obtained from Solid Lesions of the Pancreas: A Review

Advanced methods of molecular characterization have elucidated the genetic, epigenetic, and proteomic alterations associated with the broad spectrum of pancreatic disease, particularly neoplasia. Next-generation sequencing, in particular, has revealed the genomic diversity among pancreatic ductal adenocarcinoma, neuroendocrine and acinar tumors, solid pseudopapillary neoplasm, and other pancreatico-biliary neoplasms. Differentiating these entities from one another by morphologic analysis alone may be challenging, especially when examining the small quantities of diagnostic material inherent to cytologic specimens. In order to enhance the sensitivity and specificity of pancreatic cytomorphology, multiple diagnostic, prognostic, and predictive ancillary tests have been and continue to be developed. Although a great number of such tests have been developed for evaluation of specimens collected from cystic lesions and strictures, ancillary techniques also play a significant role in the evaluation of cytologic specimens obtained from solid lesions of the pancreas. Furthermore, while some tests have been developed to differentiate diagnostic entities from one another, others have been developed to simply identify dysplasia and malignancy. Ancillary studies are particularly important in the subset of cases for which cytomorphologic analysis provides a result that is equivocal or insufficient to guide clinical management. Selection of appropriate ancillary testing modalities requires familiarity with both their methodology and the molecular basis of the pancreatic diseases for which testing is being performed.

The cell tube block technique and an immunohistochemistry panel including Wilms tumor 1 to assist in diagnosing cavitary effusions in dogs and cats

BACKGROUND

Cell blocks and immunohistochemistry (IHC) are increasingly recognized as being complementary tools for cytologic diagnostics, especially for neoplastic diseases.

OBJECTIVES

The study aimed to evaluate the utility of cell tube block (CTB) IHC for refining the diagnosis of effusions in dogs and cats.

METHODS

Cavitary effusions (n = 25) from dogs and cats classified by cytology as reactive, neoplastic, borderline (suspicious of neoplasia), and chylous were studied. CTB sections were stained with H&E, and immunostained with PAX-5, CD3, pancytokeratin (CK), vimentin, and Wilms tumor 1 protein (WT1) antibodies, according to the cytologic diagnoses. A histologic case series of confirmed normal, reactive, and neoplastic mesothelium and several different carcinomas were included to test the utility of WT1 as a marker of mesothelial cells.

RESULTS

CTBs had a layered appearance with reduced background staining. CD3 and PAX5 immunolabeling allowed immunophenotype assessment in all of the lymphoma cases. In carcinomatous effusions, neoplastic cells were CK-positive, WT1-negative, and vimentin-negative (except for two cases). Wilms tumor 1 protein was positive in the nuclei of normal, reactive, and neoplastic mesothelial cells, and ovarian carcinomatous cells. Other carcinomas and lymphomas were negative.

CONCLUSIONS

CTBs are valuable tools to assist in making a diagnosis of cavitary effusions in dogs and cats, and WT1 is a promising marker to differentiate mesothelial from carcinomatous cells.

Precision cytopathology: expanding opportunities for biomarker testing in cytopathology

Precision cytopathology refers to therapeutically linked biomarker testing in cytopatology, a dynamically growing area of the discipline. This review describes basic steps to expand precision cytopathology services. Focusing exclusively on solid tumors, the review is divided into four sections: Section 1: Overview of precision pathology- opportunities and challenges; Section 2: Basic steps in establishing or expanding a precision cytopathology laboratory; Section 3: Cytopathology specimens suitable for next generation sequencing platforms; and Section 4: Summary. precision cytopathology continues to rapidly evolve in parallel with expanding targeted therapy options. Biomarker assays (companion diagnostics) comprise a multitude of test types including immunohistochemistry, in situ hybridization and molecular genetic tests such as PCR and next generation sequencing all of which are performable on cytology specimens. Best practices for precision cytopathology will incorporate traditional diagnostic approaches allied with careful specimen triage to enable successful biomarker analysis. Beyond triaging, cytopathologists knowledgeable about molecular test options and capabilities have the opportunity to refine diagnoses, prognoses and predictive information thereby assuming a lead role in precision oncology biomarker testing.

Best Practices Recommendations for Diagnostic Immunohistochemistry in Lung Cancer

Since the 2015 WHO classification was introduced into clinical practice, immunohistochemistry (IHC) has figured prominently in lung cancer diagnosis. In addition to distinction of small cell versus non-small cell carcinoma, patients' treatment of choice is directly linked to histologic subtypes of non-small cell carcinoma, which pertains to IHC results, particularly for poorly differentiated tumors. The use of IHC has improved diagnostic accuracy in the classification of lung carcinoma, but the interpretation of IHC results remains challenging in some instances. Also, pathologists must be aware of many interpretation pitfalls, and the use of IHC should be efficient to spare the tissue for molecular testing. The International Association for the Study of Lung Cancer Pathology Committee received questions on practical application and interpretation of IHC in lung cancer diagnosis. After discussions in several International Association for the Study of Lung Cancer Pathology Committee meetings, the issues and caveats were summarized in terms of 11 key questions covering common and important diagnostic situations in a daily clinical practice with some relevant challenging queries. The questions cover topics such as the best IHC markers for distinguishing NSCLC subtypes, differences in thyroid transcription factor 1 clones, and the utility of IHC in diagnosing uncommon subtypes of lung cancer and distinguishing primary from metastatic tumors. This article provides answers and explanations for the key questions about the use of IHC in diagnosis of lung carcinoma, representing viewpoints of experts in thoracic pathology that should assist the community in the appropriate use of IHC in diagnostic pathology.