Comprehensive Genomic Studies on the Cell Blocks of Pancreatic Cancer.

Pancreatic cancer is one of the deadliest malignancies, characterized by late-stage diagnosis and limited treatment options. Comprehensive genomic profiling plays an important role in understanding the molecular mechanisms underlying the disease and identifying potential therapeutic targets. Cell blocks (CBs), derived from EUS-FNA, have become valuable resources for diagnosis and genomic analysis. We examine the molecular profile of pancreatic ductal adenocarcinoma (PDAC) using specimens obtained from CB EUS-FNA, across a large gene panel, within the framework of next-generation sequencing (NGS). Our findings revealed that over half (55%) of PDAC CB cases provided adequate nucleic acid for next-generation sequencing, with tumor cell percentages averaging above 30%. Despite challenges such as low DNA quantification and degraded DNA, sequencing reads showed satisfactory quality control statistics, demonstrating the detection of genomic alterations. Most cases (84.6%) harbored at least one gene variant, including clinically significant gene mutation variants such as KRAS, TP53, and CDKN2A. Even at minimal concentrations, as long as the extracted DNA is of high quality, performing comprehensive molecular profiling on PDAC samples from cell blocks has remained feasible. This strategy has yielded valuable information about the diagnosis, genetic landscape, and potential therapeutic targets, aligning closely with a precision cytopathology approach.

A comparative study of INSM1 (clone MRQ70) immunoreactivity on CytoLyt® pretreated cytology and resection specimens of pancreatic neuroendocrine tumors.

INTRODUCTION: Insulinoma-associated protein 1 (INSM1) is a newly characterized sensitive and specific immunohistochemical marker for neuroendocrine (NE) tumors. Whereas more traditional NE markers, such as chromogranin A and synaptophysin, are cytoplasmic, INSM1 is uniquely nuclear and thus could serve as a useful addition to NE tumor workup. While application of immunohistochemical studies to cytology specimens is becoming increasingly relevant, knowledge of the effects of the certain fixatives as well as the pattern and intensity of immunoexpression are important considerations. METHODS: Sixteen cases of pancreatic neuroendocrine tumor (PanNET) diagnosed between 2015 and 2021 underwent both fine-needle aspiration, which was subsequently prepared in CytoLyt®-fixed cytology cell block (CCB), and surgical resection, in which specimens were prepared into formalin-fixed paraffin embedded blocks (FFPE). For all samples, INSM1 immunoreactivity was classified according to staining intensity and extent, then compared between CCBs and matched FFPEs. RESULTS: All 16 FFPE specimens demonstrated strong and diffuse INSM1 immunoreactivity, while only 10/16 (62.5%) CCBs were positive. Of those 10, only 2/10 (20%) demonstrated strong and diffuse reactivity. CONCLUSION: The choice of fixative has a demonstrable effect on the immunoreactivity of INSM1 in PanNET. Even though the sensitivity is lower in CytoLyt®-fixed cell block specimens, the addition of INSM1 is useful, especially in challenging cases that may be negative for one or more of the traditional NE markers.

Cell block practices in European cytopathology laboratories.

BACKGROUND: There are numerous methods and procedures described for the preparation of cell blocks (CBs) from cytological samples. The objective of this study was to determine current practices and issues with CBs in European laboratories. METHODS: A link to an online survey, with 11 questions about CB practices, was distributed to cytology laboratories via participants of United Kingdom National External Quality Assurance Service for Cellular Pathology Techniques and national representatives in the European Federation of Cytology Societies. RESULTS: A total of 402 laboratories responded completely (337/402, 84%) or partially (65/402, 16%) to the survey by February 4, 2022. The most common CB practice is embedding cell pellets using plasma and thrombin (23.3%), agar (17.1%), Shandon/Epredia Cytoblock (11.4%), HistoGel (7.9%), and Cellient (3.5%). Other methods such as CytoFoam, albumin, gelatin, Cytomatrix, and collodion bags are rarely used (1.0%, 0.7%, 0.7%, 0.3%, and 0.2%, respectively). CBs are also prepared from naturally occurring clots or tissue fragments (29.5%) and cells scraped from unstained or prestained smears (4.4%). The most frequent issues with the CBs in a daily cytology practice are low cellularity (248/402, 62%) and dispersed cells (89/402, 22%), regardless of the CBs preparation method or how the samples for embedding were selected. CONCLUSIONS: There is a great variability in CB practices in European laboratories with low cellular CBs as the main issue. Additional studies are mandatory to evaluate and improve performance and cellular yield of CBs.

Immunotherapy and lung cytopathology: Overview and possibilities.

Immunotherapy has become a promising cancer treatment in the past decade, and IHC is the most commonly used testing method for PDL-1/PD1 evaluation. In general, PD-L1 assays can be performed on both FFPE specimens and cytological samples. However, their use on smears is not yet well-established or validated. Nowadays, digital images and advanced algorithms can aid in interpreting PD-L1 in cytological samples. Understanding the immune environment of non-small cell lung cancer (NSCLC) is critical in developing successful anticancer immunotherapies. The use of a multiplexed immunofluorescence (mIF) assay on cytological samples obtained through minimally invasive methods appears to be a viable option for investigating the immune environment of NSCLC. This review aims to briefly summarize the knowledge of the role of cytopathology in the analysis of PD-L1 by immunocytochemistry (ICC) and future directions of cytopathology in the immunotherapy setting.

Programmed Death Ligand-1 Testing in Adenocarcinoma Lung: A Comparative Study of Cell Block versus Biopsy.

Background: Immunotherapy currently stands as a novel treatment option, specifically in cases of advanced non-small cell lung carcinoma (NSCLC). Expression of programmed death ligand-1 (PD-L1) in tumor cells forms the mainstay for the use of anti-PD-L1 monoclonal antibodies in the treatment of NSCLC. Aims: The objectives of the study were to assess utility of cell blocks for testing of PD-L1 in adenocarcinoma lung and to compare the expression of PD-L1 in cell blocks and the corresponding biopsy specimens. Materials and Methods: The current study was a prospective case series that included 20 cases of NSCLC-adenocarcinoma lung. Cases included in the study had biopsies performed from lung masses, along with which cell blocks were prepared from fine needle aspiration cytology (FNAC) samples. Testing for PD-L1 was done using the monoclonal PD-L1 antibody, SP-263 clone on the Ventana Benchmark XT system. PD-L1 expression was assessed only in the tumor cells, and cases with >1% expression, cytoplasmic or membranous, in tumor cells were categorized as positive. Results: PD-L1 expression was identified in the biopsy samples of tumor cells of 20% of cases (n = 4/20). In the corresponding cell blocks, PD-L1 expression was identified in the tumor cells of 15% of cases (n = 3/20). Sensitivity and specificity of cell blocks were 75% and 100%, respectively. Positive and negative predictive values were 100% and 94.12%, respectively. Conclusion: PD-L1 testing has both predictive and prognostic implications. PD-L1 testing in cell block samples is a potential alternative, specifically in cases where biopsy tissue is minimal or unavailable.

Morphological and Immunocytochemical Characterization of Tumor Spheroids in Ascites from High-Grade Serous Carcinoma.

Tumor spheroids in the ascites of high-grade serous carcinoma (HGSC) are poorly described. Our objective was to describe their morphological features, cellular composition, PD-1 and PD-L1 expression, and survival correlation of these parameters. The density and size of spheroids were assessed in Giemsa-stained smears; the cell composition of spheroids, including tumor cells, immune cells, capillaries, and myofibroblasts, as well as PD-1 and PD-L1 expression on tumor and immune cells was assessed in immunocytochemically stained cell block sections. Forty-seven patients with primary HGSC and malignant ascites were included. A cut-off value for a spheroid density of 10% was established, which significantly predicted overall survival. However, spheroid size did not correlate with survival outcomes. Spheroids were primarily composed of tumor cells, but the presence of lymphocytes and macrophages was also confirmed. Moreover, capillaries were present in the spheroids of three patients, but the presence of myofibroblasts was not confirmed. PD-1 was expressed on lymphocytes but not on tumor cells. PD-L1 expression was seen on both tumor and immune cells, assessed by 22C3 and SP263 antibody clones but not by the SP142 clone. Our results highlight the potential of routine cytopathological techniques to analyze spheroids in HGSC ascites as a valuable tool to investigate their potential as prognostic markers.

The Contribution of Cell Blocks in the Diagnosis of Mediastinal and Hilar Lymphadenopathy Samples From Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration (EBUS-TBNA).

Background Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a diagnostic procedure that allows clinicians to stage lung cancer by sampling lymph nodes in the mediastinum. EBUS-TBNA is recommended as a first step prior to mediastinoscopy for lung cancer mediastinal staging. This procedure has greatly aided pulmonologists in diagnosing mediastinal pathologies with substantial progress. In this study, our aim is to analyze how cell blocks affect the diagnostic yield of mediastinal and hilar lymphadenopathy using an EBUS cytology needle. Methods This retrospective study was conducted at King Abdulaziz University Hospital between May 2021 and September 2021. Patients with mediastinal and hilar lymphadenopathy in the absence of known or suspected primary lung cancer were included. The EBUS procedure was performed using a flexible bronchoscope equipped with a working channel suitable for transbronchial needle aspiration under direct ultrasound guidance. Data were recorded using Microsoft Excel and analyzed using Statistical Package for the Social Sciences (SPSS) v. 26.0 (IBM Corp., Armonk, NY). Diagnostic accuracy measures were determined, and a p-value of 0.05 was established as the final threshold for statistical significance. Results The total number of patients in our study was 151. The sensitivity for cytology specimens, histology specimens, and a combined evaluation for the full group of patients was 77.14%, 83.33%, and 87.5%, respectively, with a negative predictive value of 27.22%, 25%, and 21.42%. The diagnostic accuracy for cytology specimens, histology specimens, and a combined evaluation was 71.42%, 76.19%, and 80%, respectively. Conclusion Our study found that the combined examination of specimens for both cytology and histology in the diagnosis of lung cancer, sarcoidosis, and tuberculosis resulted in a higher diagnostic yield compared to cytological assessment alone using EBUS-TBNA.

Quality of cell blocks prepared from residual pleural effusion and bronchial washing samples for immunocytochemistry.

INTRODUCTION: Cell blocks (CBs) enable the long-term preservation of cytological samples. The aim of this study was to analyse the quality of CBs prepared from leftover fluid from lung adenocarcinoma pleural effusion samples and residual bronchial washing sediment for immunocytochemistry. METHODS: The residual part of 455 lung adenocarcinoma pleural effusion samples and sediment from 384 bronchial washing samples were used to prepare CBs following the agarose method. The quality of CBs was evaluated based on the quantity of malignant cells in haematoxylin and eosin-stained slides and interpreted as optimal or insufficient for immunocytochemistry. Immunocytochemistry on CBs was performed using the Dako EnVision™ FLEX detection visualisation system. The CB results for TTF-1, ALK, and PD-L1 immunocytochemistry were compared with the corresponding cytological smears. RESULTS: Among all CBs, 202 (44.4%) from leftover pleural effusion fluid and 85 (22.1%) from residual bronchial washing sediment had an optimal number of lung adenocarcinoma cells. Eight pleural effusion CBs were stained for TTF-1. Four pleural effusion and two bronchial washing CBs were stained for ALK and PD-L1. All tested pleural effusion CBs were confirmed positive for TTF-1 and negative for ALK. The PD-L1 tumour proportion score (TPS) was ≥ 50% in two pleural effusions. ALK was confirmed negative in bronchial washing CBs. One bronchial washing CB was interpreted as PD-L1-negative while the corresponding smear was positive (TPS ≥1%; 2%). CONCLUSION: The CB results of TTF-1, ALK, and PD-L1 corresponded to the findings for the smears. The inclusion of CBs prepared from leftover fluid from pleural effusion samples and residual bronchial washing sediment in routine cytological practice could provide a source of high-quality material for immunocytochemistry in addition to smears and cytospins.

Deep Learning-Based Classification and Targeted Gene Alteration Prediction from Pleural Effusion Cell Block Whole-Slide Images.

Cytopathological examination is one of the main examinations for pleural effusion, and especially for many patients with advanced cancer, pleural effusion is the only accessible specimen for establishing a pathological diagnosis. The lack of cytopathologists and the high cost of gene detection present opportunities for the application of deep learning. In this retrospective analysis, data representing 1321 consecutive cases of pleural effusion were collected. We trained and evaluated our deep learning model based on several tasks, including the diagnosis of benign and malignant pleural effusion, the identification of the primary location of common metastatic cancer from pleural effusion, and the prediction of genetic alterations associated with targeted therapy. We achieved good results in identifying benign and malignant pleural effusions (0.932 AUC (area under the ROC curve)) and the primary location of common metastatic cancer (0.910 AUC). In addition, we analyzed ten genes related to targeted therapy in specimens and used them to train the model regarding four alteration statuses, which also yielded reasonable results (0.869 AUC for ALK fusion, 0.804 AUC for KRAS mutation, 0.644 AUC for EGFR mutation and 0.774 AUC for NONE alteration). Our research shows the feasibility and benefits of deep learning to assist in cytopathological diagnosis in clinical settings.

Detection of Lymphoid Markers (CD3 and PAX5) for Immunophenotyping in Dogs and Cats: Comparison of Stained Cytology Slides and Matched Cell Blocks.

Immunolabeling on Romanowsky-stained cytology (RSC) slides can be used, although there is limited evidence of its suitability for phenotyping canine and feline lymphomas. A comparison with matched cell blocks (CB) is missing. Immunolabeling on RSC and CB was compared for lymphoid markers (CD3 and PAX5) in 53 lymphomas and 4 chylous effusions from dogs and cats. The influence of pre-analytical variables (species, time of archive, type of specimens and coverslipping) and the interobserver agreement among the 2 observers was assessed. Fewer CD3+ lymphocytes were identified in RSC, while the PAX5 positivity by RSC and CB had a substantial agreement. Immunodetection of CD3 and the diagnosis of a T-cell population on RSC was more difficult. Lower intensity and higher background were noted in RSC. Immunophenotyping was inconclusive in 54% RSC and 19% CB. The interobserver reproducibility of immunophenotyping on CB was substantial, being higher than in RSC. The immunolabeling performance on the RSC of effusion and feline samples was unsatisfactory. The detection of lymphoid markers, especially membranous antigens in retrospective RSC, is affected by the pre-analytical variables: species, time of the archive, and type of specimens. CB are a more consistent type of sample for immunophenotyping purposes.

Cell Blocks from Ultrasound Guided Fine Needle Aspirates: Diagnostic Yield in a Series of 51 Dermatologic Lesions / Bloques celulares obtenidos de la punción-aspiración con aguja fina ecoguiada: rendimiento diagnóstico en una serie de 51 lesiones dermatológicas

The generation of cell blocks (CB) obtained from ultrasound-guided fine needle aspiration biopsies (USFNAB) is a well-established technique in breast and thyroid pathology, but is rarely used in dermatology. We reviewed CBs obtained from USFNAB of skin lesions, which were categorized as malignant skin tumors, benign skin tumors, inflammatory skin tumors or deposit skin diseases. The diagnostic yield of each category was compared to histopathology. The USFNAB of 51 skin lesions was processed into CBs. There was overall agreement between histopathology and CBs in 84.31% of cases. Diagnostic group concordance for benign, malignant as well as inflammatory and deposit skin lesions were 69.2%, 93.7% and 86.3% respectively. Cell block generation from USFNAB aspirates of skin lesions should be considered as part of the dermatologic diagnostic armamentarium. Further experience is needed to better understand for which types of dermatologic lesions it would be clearly indicated (AU)

La generación de bloques celulares (CBs) obtenidos a partir de punción-aspiración con aguja fina guiada por ultrasonido (USFNAB), es una técnica bien establecida en patología mamaria y tiroidea, pero rara vez se utiliza en dermatología. Revisamos los CBs obtenidos por USFNAB de lesiones cutáneas, que se clasificaron como tumores cutáneos malignos, tumores cutáneos benignos, tumores cutáneos inflamatorios o enfermedades cutáneas por depósito. El rendimiento diagnóstico de cada categoría se comparó con la histopatología. La USFNAB de 51 lesiones cutáneas se procesó en CBs. Hubo concordancia global entre la histopatología y los CBs en el 84,31% de los casos. La concordancia entre histopatología y CBs para lesiones cutáneas benignas, malignas e inflamatorias y por depósito fue del 69,2, 93,7 y 86,3%, respectivamente. La generación de CBs a partir de USFNAB de lesiones cutáneas debe considerarse como parte del arsenal diagnóstico dermatológico. Se necesita más experiencia para comprender mejor para qué tipos de lesiones dermatológicas estaría claramente recomendado (AU)

[Artículo traducido] Bloques celulares obtenidos de la punción-aspiración con aguja fina ecoguiada: rendimiento diagnóstico en una serie de 51 lesiones dermatológicas / Cell Blocks from Ultrasound Guided Fine Needle Aspirates: Diagnostic Yield in a Series of 51 Dermatologic Lesions

La generación de bloques celulares (CBs) obtenidos a partir de punción-aspiración con aguja fina guiada por ultrasonido (USFNAB), es una técnica bien establecida en patología mamaria y tiroidea, pero rara vez se utiliza en dermatología. Revisamos los CBs obtenidos por USFNAB de lesiones cutáneas, que se clasificaron como tumores cutáneos malignos, tumores cutáneos benignos, tumores cutáneos inflamatorios o enfermedades cutáneas por depósito. El rendimiento diagnóstico de cada categoría se comparó con la histopatología. La USFNAB de 51 lesiones cutáneas se procesó en CBs. Hubo concordancia global entre la histopatología y los CBs en el 84,31% de los casos. La concordancia entre histopatología y CBs para lesiones cutáneas benignas, malignas e inflamatorias y por depósito fue del 69,2, 93,7 y 86,3%, respectivamente. La generación de CBs a partir de USFNAB de lesiones cutáneas debe considerarse como parte del arsenal diagnóstico dermatológico. Se necesita más experiencia para comprender mejor para qué tipos de lesiones dermatológicas estaría claramente recomendado (AU)

The generation of cell blocks (CB) obtained from ultrasound-guided fine needle aspiration biopsies (USFNAB) is a well-established technique in breast and thyroid pathology, but is rarely used in dermatology. We reviewed CBs obtained from USFNAB of skin lesions, which were categorized as malignant skin tumors, benign skin tumors, inflammatory skin tumors or deposit skin diseases. The diagnostic yield of each category was compared to histopathology. The USFNAB of 51 skin lesions was processed into CBs. There was overall agreement between histopathology and CBs in 84.31% of cases. Diagnostic group concordance for benign, malignant as well as inflammatory and deposit skin lesions were 69.2%, 93.7% and 86.3% respectively. Cell block generation from USFNAB aspirates of skin lesions should be considered as part of the dermatologic diagnostic armamentarium. Further experience is needed to better understand for which types of dermatologic lesions it would be clearly indicated (AU)

Chondroblastoma: Cytomorphologic Analysis of 10 Cases with Review of the Literature.

INTRODUCTION: Chondroblastoma (CB) is a rare, benign cartilage-producing tumor, typically affecting the epiphysis of long bones in skeletally immature individuals. There have been only limited case reports describing the cytomorphologic features of this tumor, and thus the cytopathologic diagnostic criteria are controversial. Herein, we report the cytologic findings of 10 CB cases, discuss the diagnostic criteria and critical differential diagnosis, along with a comprehensive review of the literature. METHODS: We performed a retrospective search of our cytopathology and surgical pathology databases for cases diagnosed as CB that had corresponding cytology specimens from four large medical institutions. All available cytopathology specimens were retrieved and reviewed. Clinicopathologic and radiologic data were recorded. RESULTS: Ten cases were retrieved from 8 patients aged 15-42 years (mean, 24 years), five of whom were males. Eight cases represented primary tumors while 2 cases were recurrences. Three cases occurred in the femur, two cases occurred in the humerus, while 1 case occurred in each of the glenoid, talus, and proximal phalanx of the 3rd toe. The cytologic diagnosis of CB was achieved in 7 cases. The neoplastic mononuclear cells were present in all cases and their cytologic features were similar. These cells displayed round to oval eccentric nuclei, evenly distributed chromatin, and inconspicuous nucleoli; few of which had nuclear indentations. Multinucleated giant cells were present in 9 cases (90%). Fragments of chondromyxoid matrix were present in 4 cases on cytologic preparations (40%). Cell blocks were available in 8 cases. Mononuclear and multinucleated giant cells were present in all adequate cell blocks and their cytologic features were identical to those seen in the smears. The chondroid matrix was present in only three of the adequate cell blocks (43%). CONCLUSION: We concluded that with the appropriate clinical and radiologic setting, the diagnosis of CB can be achieved on cytology if characteristic chondroblasts are present. The presence of chondromyxoid matrix is a helpful clue but is not necessary for the diagnosis. As in surgical pathology, cytologic evaluation of bone tumors should be interpreted in conjunction with clinical and radiologic findings.

Cutoff values of PD-L1 expression in urinary cytology samples for predicting response to immune checkpoint inhibitor therapy in upper urinary tract urothelial carcinoma.

BACKGROUND: The objective of this study was to determine the cutoff value of PD-L1 expression that can predict response to immune checkpoint inhibitor (ICI) immunotherapy for upper tract urothelial carcinoma (UTUC). METHODS: The concordance of PD-L1 expression between paired surgical resection specimens (SRSs) and urine cell blocks (UCBs) (cohort 1) was studied in a retrospective set of 58 UTUC patients to determine its suitability as a predictor of ICI immunotherapy efficacy. PD-L1 expression in UCBs obtained before neoadjuvant ICI immunotherapy was verified in a prospective set of 12 UTUC patients (cohort 2). PD-L1 (SP263 clone) expression was assessed for percentage (tumor proportional score) of tumor cell (TC) showing PD-L1 staining. RESULTS: The authors found an overall agreement of 94.4% (51 of 54) between UCBs and SRSs in cohort 1 (positive percent agreement = 100%, negative percent agreement = 93.8%, r value = 0.63). PD-L1 expression in <10% and ≥10% of tumor cells (TCs) of UCBs were the best predictors of negative (<25%) and positive (≥25%) expression in TCs of SRSs, respectively (concordance = 98.1%, r value = 0.93). These findings were verified in cohort 2: at the 10% cutoff for PD-L1 expression, the best response predictive value was 83.3% (5 of 6) in PD-L1-positive patients, and the nonresponse predictive value was 50% (3 of 6) in PD-L1-negative patients. The sensitivity, specificity, and area under the receiver operating characteristic curve values for predicting ICI immunotherapy efficacy based on PD-L1-expressing TCs in UCBs were 62.5%, 75%, and 0.688, respectively. CONCLUSIONS: Immunocytochemistry of UCBs is reliable for determining PD-L1 expression, which can predict the efficacy of ICI immunotherapy at a cutoff of 10%.

Cell Blocks from Ultrasound Guided Fine Needle Aspirates: Diagnostic Yield in a Series of 51 Dermatologic Lesions.

The generation of cell blocks (CB) obtained from ultrasound-guided fine needle aspiration biopsies (USFNAB) is a well-established technique in breast and thyroid pathology, but is rarely used in dermatology. We reviewed CBs obtained from USFNAB of skin lesions, which were categorized as malignant skin tumors, benign skin tumors, inflammatory skin tumors or deposit skin diseases. The diagnostic yield of each category was compared to histopathology. The USFNAB of 51 skin lesions was processed into CBs. There was overall agreement between histopathology and CBs in 84.31% of cases. Diagnostic group concordance for benign, malignant as well as inflammatory and deposit skin lesions were 69.2%, 93.7% and 86.3% respectively. Cell block generation from USFNAB aspirates of skin lesions should be considered as part of the dermatologic diagnostic armamentarium. Further experience is needed to better understand for which types of dermatologic lesions it would be clearly indicated.

Cell Blocks from Ultrasound Guided Fine Needle Aspirates: Diagnostic Yield in a Series of 51 Dermatologic Lesions. / [Artículo traducido] Bloques celulares obtenidos de la punción-aspiración con aguja fina ecoguiada: rendimiento diagnóstico en una serie de 51 lesiones dermatológicas.

The generation of cell blocks (CBs) obtained from ultrasound-guided fine needle aspiration biopsies (USFNAB) is a well-established technique in breast and thyroid pathology, but is rarely used in dermatology. We reviewed CBs obtained from USFNAB of skin lesions, which were categorized as malignant skin tumors, benign skin tumors, inflammatory skin tumors or deposit skin diseases. The diagnostic yield of each category was compared to histopathology. The USFNAB of 51 skin lesions was processed into CBs. There was overall agreement between histopathology and CBs in 84.31% of cases. Diagnostic group concordance for benign, malignant as well as inflammatory and deposit skin lesions were 69.2%, 93.7% and 86.3% respectively. Cell block generation from USFNAB aspirates of skin lesions should be considered as part of the dermatologic diagnostic armamentarium. Further experience is needed to better understand for which types of dermatologic lesions it would be clearly indicated.

The optimal approach of EBUS-FNA rapid on-site evaluation (ROSE): a five-year experience from a large academic medical center.

INTRODUCTION: Rapid on-site evaluation (ROSE) performed during endobronchial ultrasound-guided fine needle aspiration (EBUS-FNA) has shown significant value. However, ROSE may not be available for some pulmonary centers. Performing ROSE can be challenging and stressful due to time constrains for preparing, staining and reviewing the cytology slides between passes. MATERIALS AND METHODS: A retrospective cytology report review of EBUS-FNA procedures performed between October 2014 and May 2019 revealed 516 cases that were included in the study. The number of passes for each procedure was documented. The adequacy rates were assessed at 4 different study points; ≤3 passes, ≤5 passes, at odd passes only, and the even passes only. The study groups results were compared to the overall ROSE and the final cytology adequacy. RESULTS: The overall ROSE interpretation was adequate in 370 (71.7%) and inadequate in 146 (28.3%). After reviewing the Papanicolaou stained slides and cell blocks, the final cytology results were adequate in 473 (91.7%) and inadequate in 43 (8.3%) of the cases. The number of passes per procedure ranged from 1 to 17. Our results showed that ROSE evaluation of the first 5 passes during the EBUS-FNA procedure could achieve the similar adequacy rate compared to the overall ROSE evaluation of all the passes. CONCLUSIONS: To achieve the most benefits of ROSE and to reduce the procedure time for EBUS-FNA, we recommend performing ROSE for ≤5 passes depending on the adequacy, and save all additional passes for cell blocks preparation if more than 5 passes are attempted.

Bronchoalveolar Lavage as a Diagnostic Tool in an Atypical Pulmonary Langerhans Cell Histiocytosis.

Pulmonary Langerhans cell histiocytosis (PLCH) is an uncommon diffuse cystic lung disease that occurs almost exclusively in young adult smokers. High-resolution computed tomography of the chest allows a confident diagnosis of PLCH in typical presentation, when nodules, cavitating nodules, and cysts coexist and show a predominance for the upper and middle lung. Atypical presentations require histology for diagnosis. Histologic diagnosis rests on the demonstration of increased numbers of Langerhans cells and/or specific histological changes. PLCH is one of the few diseases in which bronchoalveolar lavage (BAL) has a high diagnostic value and can in some circumstances replace lung biopsy. We present a case of PLCH in an elderly non-smoker. Chest imaging revealed the presence of advanced interstitial lung disease with a fibrocystic pattern. BAL cellular analyses disclosed a macrophage pattern with CD1a phenotype that strongly supports the PLCH diagnosis, even in the setting of atypical clinical presentation and a lack of smoking exposure. PLCH is extremely rare in non-smokers and could represent a distinct phenotype.

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.

Immunoexpression of oral brush biopsy enhances the accuracy of diagnosis for oral lichen planus and lichenoid lesions.

BACKGROUND: This study assessed the efficacy of using oral liquid-based brush cytology (OLBC) coupled with immunostained cytology-derived cell-blocks, quantified using machine-learning, in the diagnosis of oral lichen planus (OLP). METHODS: Eighty-two patients diagnosed clinically with either OLP or oral lichenoid lesion (OLL) were included. OLBC samples were obtained from all patients before undergoing surgical biopsy. Liquid-based cytology slides and cell-blocks were prepared and assessed by cytomorphology and immunocytochemistry for four antibodies (Ki-67, BAX, NF-κB-p65, and AMACR). For comparison purposes, a sub-group of 31 matched surgical biopsy samples were selected randomly and assessed by immunohistochemistry. Patients were categorized according to their definitive diagnoses into OLP, OLL, and clinically lichenoid, but histopathologically dysplastic lesions (OEDL). Machine-learning was utilized to provide automated quantification of positively stained protein expression. RESULTS: Cytomorphological assessment was associated with an accuracy of 77.27% in the distinction between OLP/OLL and OEDL. A strong concordance of 92.5% (κ = 0.84) of immunostaining patterns was evident between cell-blocks and tissue sections using machine-learning. A diagnostic index using a Ki-67-based model was 100% accurate in detecting lichenoid cases with epithelial dysplasia. A BAX-based model demonstrated an accuracy of 92.16%. The accuracy of cytomorphological assessment was greatly improved when it was combined with BAX immunoreactivity (95%). CONCLUSIONS: Cell-blocks prepared from OLBC are reliable and minimally-invasive alternatives to surgical biopsies to diagnose OLLs with epithelial dysplasia when combined with Ki-67 immunostaining. Machine-learning has a promising role in the automated quantification of immunostained protein expression.