Cell Block Sections Research Articles

Cytologic diagnosis of fumarate hydratase-deficient renal cell carcinoma: A single-institutional experience.

Fumarate hydratase-deficient renal cell carcinoma (FHRCC) is an aggressive carcinoma that typically presents as advanced-stage disease. Prompt recognition of FHRCC is critical for appropriate clinical care and genetic counseling for patients and family members. However, diagnosing FHRCC from cytology specimens is challenging, with limited characterization and no reports describing prospectively identified cases. Cytology fine-needle aspiration (FNA) cases diagnosed as FHRCC were reviewed, including two prospectively identified cases. Five cases of FHRCC diagnosed by FNA cytology were identified in five unique patients. The cytologic samples included four FNAs with core biopsy and one FNA with cell block. Biopsy sites included kidney (n=1), chest wall (n=1), omentum (n=1), lung (n=1), and cervical lymph node (n=1). All cases demonstrated cytologically malignant epithelial cells characterized by enlarged, round nuclei with variable pleomorphism, irregular nuclear membranes, prominent nucleoli, and moderate-to-abundant amounts of cytoplasm. Perinucleolar halos characterized by chromatin margination and pallor around macronucleoli were seen in all cases. Cytologic features not previously described included cytoplasmic macrovacuoles and eosinophilic globules, cytophagocytosis, and floral groups. Papillary architecture was rarely present on aspirate smears. Cell block sections showed variable architectural patterns. By immunohistochemistry, FH was definitively lost in three of five cases (60%), and 2-succinocysteine was positive in all 5 cases (100%). Cytologic specimens of FHRCC demonstrate salient cytomorphologic features that can support their initial diagnosis. Confirmatory immunohistochemical testing using a dual panel of fumarate hydratase and 2-succinocysteine is recommended for the diagnosis in limited biopsy samples.

New Instant Digital Pathology for EUS/EBUS Samples: The Last Advance in Bedside Diagnostics for Lung Carcinoma.

Background: Ex vivo fluorescence laser scanning microscopes (FCMs) allow digital tissue imaging directly from fresh, unfixed specimens without the need for conventional histological slide preparation. To date, no data have been reported on the use of FCMs in the endoscopy suite for immediate evaluation of endoscopic ultrasound (EUS)/endobronchial ultrasound (EBUS) fine needle aspiration/biopsy (FNA-B) specimens of lung lesions and/or mediastinal lymph nodes. Objectives: The aim of this study was to evaluate the performance of the FCM Vivascope 2500 (Vivascope, Munich, Germany) in providing real-time adequacy assessment and diagnostic information on the digital images of fresh unprocessed EUS/EBUS FNA-B specimens and to compare it with the corresponding final histological sections of formalin-fixed and paraffin-embedded cell blocks. Methods and Results: Thirty-two patients (50% male; 71 ± 8 years old) were enrolled between May 2023 and June 2024. In 28/32 (87.5%) patients, samples were defined as adequate at Vivascope evaluation, and in 20/28 (71.4%) patients, samples were classified as malignant. At final cytohistological evaluation, 87.5% of specimens were defined as adequate and 20/28 (71.4%) were diagnosed as malignant. There was perfect agreement between the Vivascope assessment of adequacy and the final cytohistological assessment on the same specimen (k Cohen 1). From a diagnostic point of view, perfect agreement was found between the two techniques in the identification of malignant neoplasms (k Cohen 1). Conclusions: The use of FCM could provide rapid information on both the adequacy and malignancy of the sample obtained during EBUS tissue acquisition (EBUS-TA), with minimal or no preparation and without destroying or losing the tissue. This technique allows for obtaining representative material in EBUS/EUS for lung cancer staging and is expected to change the turnaround time from biopsy sampling to diagnostic characterization of the tumor, ultimately improving patient management both at diagnosis and at restaging in follow up.

Weakly Supervised Multiple Instance Learning Model With Generalization Ability for Clinical Adenocarcinoma Screening on Serous Cavity Effusion Pathology

Accurate and rapid screening of adenocarcinoma cells in serous cavity effusion is vital in diagnosing the stage of metastatic tumors and providing prompt medical treatment. However, it is often difficult for pathologists to screen serous cavity effusion. Fixed agglutination cell block can help to improve diagnostic sensitivity in malignant tumor cells through analyzing larger volumes of serous cavity effusion, although it could accordingly lead to screening of more cells for pathologists. With the advent of whole slide imaging and development of artificial intelligence, advanced deep learning models are expected to assist pathologists in improving diagnostic efficiency and accuracy. In this study, so far as we know, it is the first time to use cell block technology combined with a proposed weakly supervised deep learning model with multiple instance learning method to screen serous adenocarcinoma. The comparative experiments were implemented through 5-fold cross-validation, and the results demonstrated that our proposed model not only achieves state-of-the-art performance under weak supervision while balancing the number of learnable parameters and computational costs and reduces the workload of pathologists but also presents a quantitative and interpretable cellular pathologic scene of serous adenocarcinoma with superior interpretability and strong generalization capability. The performances and features of the model indicate its effectiveness in the rapid screening and diagnosis of serous cavity effusion and its potential in broad clinical application prospects, eg, in precision medical applications. Moreover, the constructed 2 real-world pathologic data sets would be the first public whole slide imaging data sets of serous cavity effusion with adenocarcinoma based on cell block sections, which can help assist colleagues.

Analysis of Candidate miRNAs' Expression in Pancreatic Cancer.

Pancreatic cancer (PC) is one of the most aggressive types of cancer. Despite advances in molecular diagnostics, PC diagnosis relies on imaging technologies and morphological assessment of fine needle aspirates (FNAs). MicroRNA (miRNA) involvement in PC pathogenesis and potential diagnostics application have been suggested, albeit current supporting evidence is lacking. Here, we investigated the association of selected miRNAs with PC incidence and clinical characteristics. Fold expression of miR-216a-3p, -217-5p, -221-3p, -222-3p, and miR-196a-5p was assessed in 73 PC FNA cell-block sections and 6 healthy pancreas tissues using Taqman advanced miRNA assays. Potential miRNA targets were ascertained using immunocytochemistry. miR-196a-5p was upregulated in PC compared to healthy pancreatic tissue (β = -0.05, 95% CI: -0.065 - (-0.035); p < 0.001). miR-221-3p and miR-222-3p fold expression were strongly correlated (r = 0.897, p < 0.001), whereas miR-196a-5p fold expression correlated with that of miR-221-3p (r = 0.688, p < 0.001) and miR-222-3p (r = 0.489, p < 0.001). Moreover, miR-196a-5p fold expression positively correlated with tumor stage (r = 0.32, p = 0.034). miR-217-5p fold expression inversely correlated with KRAS expression (r = -0.69, p = 0.0027). Our study shows miR-196a-5p has reasonable specificity to PC and thus may have diagnostic and prognostic potential in PC as proposed in the literature. Moreover, KRAS and NFKBIA may be potential targets for miR-217-5p and miR-196a-5p, respectively. Thus, these miRNAs may be involved in tumor progression and may have valuable applications in novel therapeutics or treatment monitoring.

Inter- and Intra-observer Reproducibility of Thyroid Fine Needle Aspiration Cytology: An investigation of Bethesda 2023 Using Immunohistochemical BRAFV600E Antibody.

The Bethesda System for Reporting Thyroid Cytology (TBSRTC) recommended for the interpretation of needle aspiration cytology of the thyroid, is the most widely used worldwide. Studies have shown that the disagreement between observers, especially in the Bethesda III and IV diagnostic categories, is not insignificant at 10%-40%. In the TBSRTC 2023 version, some definitions were removed and simplified, and molecular pathology was proposed as a complement to cytopathology. The current availability of molecular tests is limited because they can be performed in a few centers and are expensive. Therefore, our study investigated intra- and inter-observer agreement according to TBSRTC 2023 using only immunohistochemically BRAFV600E antibodies. The study included 173 cases with aspiration cytology evaluated between 2019 and 2022. The immunohistochemical procedure applied BRAFV600E (RM8) monoclonal antibody to cell block sections. All slides were assessed and categorized by three different observers. Data were interpreted using Cohen's kappa and Fleiss's kappa test in the Statistical Package for Social Sciences Windows 2021 program. For the applied RM8 antibody, sensitivity was 64.71% and specificity was 87.27%. In terms of diagnostic categories, inter-observer agreement was good for Bethesda II (K = 0.606) and moderate for Bethesda III (K = 0.429), Bethesda IV (K = 0.523), Bethesda V (K = 0,464), and Bethesda VI (K = 0.544), respectively. In conclusion, the study reveals that the 2023 version of TBSRTC provides improvement, especially in the categories of uncertain diagnosis, but is still insufficient to improve cytological diagnostic accuracy, at which point molecular analyses become even more important.

Pleomorphic Liposarcoma Cytologically Detected in Hemosiderotic Pleural Effusion: Pitfalls Mitigated by Cytologic Clues and Cellblock Immunocytochemistry.

Sarcomatous serous effusions are uncommon and diagnostically challenging. Dedifferentiated and pleomorphic liposarcomas are rare tumors in pleural effusions revealing highly pleomorphic tumor cells mimicking carcinoma, mesothelioma, melanoma, and other sarcomas. Hematothoracic effusions further complicate the cytologic diagnosis. Correct cytologic recognition is important. We report pleomorphic liposarcoma cytologically detected in effusion fluid in a 56-year-old man who presented with a massive unilateral pleural effusion. ThinPrep showed hemorrhagic effusion fluid characterized by lysed red blood cells, foamy macrophages, and siderophages intermixed with highly pleomorphic predominantly naked mononuclear and giant nuclei. The aggregated siderophages and vacuolated macrophages could be mistaken for tumor cells, whereas the bare nuclei may be missed as nonspecific degenerate changes. Cellblock sections showed highly pleomorphic mononuclear and multinucleated giant tumor cells with diagnostic lipoblasts, intermixed with foamy macrophages and siderophages. Cellblock immunocytochemistry showed staining for vimentin and S-100 protein in the tumor cells. Other lineage-specific immunomarkers were negative. CD68 and calretinin revealed frequent background macrophages and scarce mesothelial cells. The tumor cells were negative for MDM2 and CDK4. The entertained cytopathologic diagnosis was pleomorphic liposarcoma. Core needle biopsy was procured from the mass. The histopathologic features and immunoprofile of the tissue specimen matched the cytopathologic and immunocytochemical findings confirming the cytologic diagnosis of pleomorphic liposarcoma. Pleomorphic liposarcoma is an unexpected cytologically challenging finding in effusions, particularly when compounded by pitfalls introduced by hemosiderotic fluid. Attention to certain cytologic clues mitigate pitfalls. Cellblock is a valuable diagnostic tool when integrated with relevant negative and positive immunocytochemical markers.

Renal B-lymphoblastic lymphoma with hematuria as the first symptom diagnosed in urine cytology: A case report and literature review.

Cytological examination of urine sediment is a helpful diagnostic tool for identifying renal involvement by hematological malignancies. We present the case of a 47-year-old man who was diagnosed with extranodal B-lymphoblastic lymphomas after presenting with gross hematuria as his first symptom. The presence of lymphoma cells in the urine led to a diagnosis confirmed through an immunophenotypic study using cell block sections of urine centrifuge sediment and core needle biopsy histology of the right renal pelvis mass. This case highlights the usefulness of a urine cytological study in diagnosing lymphoma involvement in the genitourinary tract. Furthermore, this paper reviews relevant literature on diagnosing lymphoma involvement from urine sediment.

FNA of Meningioma with Rhabdoid Features Presenting as a Lateral Neck Mass.

Primary meningioma at extracranial head and neck sites is uncommon. Since fine needle aspiration (FNA) is often the first line diagnostic modality for the evaluation of masses in the head and neck, extracranial meningiomas can create a significant diagnostic pitfall for FNA. We report a case of meningioma with rhabdoid features and BAP1 loss in a 26-year-old woman, presenting as a large neck mass along the carotid sheath. FNA biopsy of the mass demonstrated a highly cellular specimen with clusters of uniform, epithelioid cells with round to ovoid nuclei and moderate nuclear to cytoplasmic ratio. An extensive immunohistochemical panel performed on cell block sections showed that the tumor cells were weakly EMA positive, progesterone receptor was focally positive, and SSTR2A was diffuse and strongly positive. BAP1 immunohistochemistry showed a diffuse loss of expression in the tumor cells. After the cytologic diagnosis of meningioma, a tissue biopsy was performed, and the diagnosis of meningioma with rhabdoid features and BAP1 loss was confirmed. We also perform a literature review of meningioma cases presenting as a neck mass and evaluated by FNA. Our case highlights the significant diagnostic challenges that can be caused by extracranial meningiomas on FNA and the importance of ancillary studies to avoid diagnostic pitfalls.

Strongyloides stercoralis infection masquerading as malignant ascites in a case of angiosarcoma.

Strongyloides stercoralis is a parasitic nematode that infects millions of people worldwide. It primarily infects humans but can also be found in domestic animals and primates. The severity of infection varies from asymptomatic to life-threatening complications. We present a case of a 56-year-old male with a known case of angiosarcoma liver with massive ascites and low-grade fever. He was clinically diagnosed as having malignant ascites and was planned for chemotherapy. During therapeutic cum diagnostic ascitic tap, cell block sections revealed the presence of cross sections of nematode S. stercoralis gravid uterus with eggs. Later, stool for ova and cysts also revealed multiple larval forms of the nematode. S. stercoralis hyperinfection is often accompanied by sepsis or meningitis with enteric organisms. Patient was started on tab. ivermectin 12 mg once a day for two days (in the standard dosage of 200 mcg/kg) was then repeated in the same dosage for another two days after two weeks, and gradually the ascites settled. Post-treatment ascitic tap cell block preparations did not show any parasites. Patient has been on follow-up for 6 months, and he remains asymptomatic.

Application of the Milan System for Reporting Salivary Gland Lesions and Its Cytohistological Correlation for Risk Stratification: A Single-Institution Experience.

Salivary gland tumors are known to have a heterogeneous profile with variable clinical presentation and a wide variety of histological subgroups of prognostic significance. Immunocytochemical markers that aid in the diagnosis and characterization of the cell type of origin are critical for this heterogeneous group of malignancies. To study the application of The 'Milan System' for Reporting Salivary Gland Cytology and the diagnostic utility of a panel of immunocytochemical markers in the diagnosis of salivary gland neoplasms and their cytohistological correlation for their risk stratification. This was a prospective study carried out in which a total of 60 patients were enrolled in the study. Fine-needle aspiration cytology (FNAC) smears and cell blocks were prepared with standard techniques and staining procedures. Immunocytochemistry (ICC) was performed on cell block sections by immunoperoxidase procedure. Immunocytochemical (ICC) stains were used for the differentiation of the lesions in cell blocks. Histopathology was also studied if the patient underwent excision of salivary gland lesions. Almost 60 cases were studied under FNAC and cell block evaluation, as well as ICC, among those five (8.33%) samples were inadequate, eight (13.3%) were non-neoplastic, 27 (45%) were benign, one (1.7%) was neoplasmwith uncertain malignancy potential, one (1.7%) was suspected of malignancy, and 19 (31.7%) were malignant.The histopathological diagnosis was confirmed in 47 cases. Of these, 24 (51.1%) were benign and 23 (48.9%) were malignant. The malignancy rate for Milan Categories I, II, III, IVa, IVb, V, and VI was 0%, 0%, 100%, 24%, 50%, 80%, and 84.6%, respectively. The study showed that malignancy risk stratification could be further improved by using cell block with immunocytochemistryas a complementary diagnostic modality. The present study was carried out to assess the usefulness of the Milan system to report salivary gland cytology results. Thus, the findings of the present study showthat the Milan system is helpful in stratifying the risk of malignancy in salivary gland tumors.

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.

Diagnostic Utility of Pleural Fluid Cytology versus Cell Block Technique: A Comparative Study

Introduction: Categorization between benign and malignant pleural effusions most often create diagnostic dilemma. Categorization often requires clinical findings and morphological evaluation. Diagnostic possibility is increased if cell blocks are performed in addition to conventional cytology smears. This will help the clinicians in both treating the patient and determining the outcome of the disease process.&#x0D; Aims: The aim of this study was to compare the smears cytology with cell blocks sections in pleural effusions.&#x0D; Methods: This hospital-based cross sectional analytical study was carried out in Department of Pathology in Nepalgunj Medical College, Nepalgunj for one year.&#x0D; Results: The four criteria scored for each technique were amount of background blood, yield of diagnostic cellular material, degree of cellular degeneration as well as cellular trauma and architectural preservation. More amount of diagnostic material present and appropriate retention of architecture was more in cell block sections compared with smears cytology; whereas cellular degeneration as well as cellular trauma and background blood was less appreciated in cell block sections which scored more than the smears cytology.&#x0D; Conclusion: Cell block method especially in clinically, radiologically and cytologically suspected malignant cases should be routinely processed for cell block method.

The Utility of Fine Needle Aspiration (FNA) Biopsy in the Diagnosis of Mediastinal Lesions.

Fine needle aspiration is a minimally invasive, low-morbidity, and cost-efficient technique for the sampling of mediastinal lesions. Additionally, ancillary testing on FNA samples can be used for the refinement of diagnoses and for treatment-related purposes (flow cytometry, cytogenetics, immunohistochemistry, and molecular diagnostics). Mediastinal lesions, however, can show a variety of lineages and morphologic features, giving rise to diagnostic dilemmas. As a result, the differential diagnosis can vary widely and becomes especially challenging due to the smaller sample size on FNA and the variability in component sampling. For appropriate patient management and to determine the correct treatment strategies, accurate pathologic diagnoses are paramount. In this review, we present the cytomorphologic features together with the immunophenotypic findings of mediastinal lesions, with emphasis on the diagnostic challenges and pitfalls in FNA cytology samples, including smears and cell block sections.

Cytological Features of a Metastatic Angiosarcoma in the Lymph Node Diagnosed via Liquid-Based Cytology.

Angiosarcoma is a soft tissue sarcoma of vascular origin, with more than half of the cases arising in the skin and affecting primarily the face and scalp of elderly males. Furthermore, cutaneous angiosarcoma exhibits a higher incidence of lymph node metastases than other types of sarcomas. Angiosarcomas are rarely aspirated and are occasionally encountered on cytological samples. It is a diagnostic challenge in evaluating fine needle aspiration (FNA) from a metastatic angiosarcoma without the knowledge of prior history. We present a case of scalp angiosarcoma with disease progression to erythroderma and cervical lymphadenopathy 20 months after. FNA of the cervical node revealed vasoformative features, including hemophagocytosis, formation of an intracytoplasmic lumen/vacuole, endothelial wrapping, and cell grasping. The diagnosis of nodal metastasis by angiosarcoma was confirmed with immunohistochemistry (IHC) using two vascular markers on cell block sections. Our case demonstrates the recognizable cytomorphologic clues for this rare metastatic malignancy.

SOX17 is a highly sensitive and specific marker for metastatic ovarian and endometrial carcinomas in cytology cell block specimens.

SOX17 (SRY-box transcription factor 17) was recently identified as a highly sensitive and specific marker for ovarian and endometrial carcinomas in surgical specimens. In this study, validation of the utility of SOX17 immunohistochemistry (IHC) in diagnosing metastatic gynecologic carcinomas in cytology specimens was sought. The study cohort included 84 cases of metastatic carcinomas that included 29 metastatic gynecologic carcinomas (24 ovarian high-grade serous carcinomas, two endometrial serous carcinomas, one low-grade serous carcinoma, one ovarian clear cell carcinoma, and one endometrial endometrioid carcinoma) and 55 cases of metastatic nongynecologic carcinomas (10 clear cell renal cell carcinomas, 10 papillary thyroid carcinomas, 11 gastrointestinal adenocarcinomas, 10 breast carcinomas, 10 lung adenocarcinomas, and four urothelial carcinomas). Cytology specimen types included peritoneal fluid (n=44), pleural fluid (n=25), and fine-needle aspiration (n=15). SOX17 IHC was performed on the cell block sections. The intensity of staining and percent positivity of the tumor cells were evaluated. SOX17 was highly expressed in all tested metastatic gynecologic carcinomas with diffuse and strong nuclear expression (29 of 29; 100%). SOX17 was negative in other metastatic nongynecologic carcinomas (54 of 55; 98.18%) except for one papillary thyroid carcinoma that showed low positivity (<10%). SOX17 is a highly sensitive (100%) and specific (98.2%) marker for the differential diagnosis of metastatic gynecologic carcinomas in cytology specimens. Therefore, SOX17 IHC should be included in the workup of differential diagnosis of metastatic gynecologic carcinomas in cytology specimens.

How to Diagnose Anaplastic Large Cell Lymphoma on Cytological Samples? A Series with Emphasis on Diagnostic Clue and Pitfalls

Introduction: Anaplastic large cell lymphoma (ALCL) is a rare mature T-cell non-Hodgkin’s lymphoma characterized by large and pleomorphic neoplastic CD30-positive T cells. ALCL includes different subtypes with different clinical and biological features: systemic ALCL, primary cutaneous ALCL, breast implant-associated ALCL (BIA-ALCL). Anaplastic lymphoma kinase (ALK) is overexpressed and rearranged in some systemic cases. Diagnosis of ALCL may be challenging on cytological samples, but the correct diagnosis is mandatory for the management of the patient. Methods: A retrospective series of 12 ALCLs diagnosed by cytology is reported. Cytological samples included lymph nodes and skin lesions fine needle aspiration cytology, peritoneal effusion, and periprosthetic fluid. Microscopic evaluation was performed on direct smears, cell-block sections, and cytocentrifugated slides. Immunocytochemistry was performed on cell-block sections, direct smears, and cytocentrifugated slides. Molecular evaluation by fluorescent in-situ hybridization (FISH) was performed on cell-block sections. Results: The series included 4 ALK+ ALCLs, 5 ALK− ALCLs, and 3 BIA-ALCLs. FNAC was performed on lymph nodes in 8 cases and on skin lesion in 1 case. In this last case, a peritoneal effusion was also evaluated. Breast periprosthetic fluids were evaluated in 3 cases. A large immunocytochemical panel was performed in each case, and FISH in 3 cases, demonstrating ALK rearrangement in a case of ALK+ ALCL. A final diagnosis was rendered in all cases. In the case of skin lesion, the differential diagnosis between systemic ALCL and primary cutaneous ALCL was possible. Conclusion: The cytological diagnosis of ALCL may be challenging, and the proper management of the collected sample is mandatory. The rapid on-site evaluation and the realization of a cell block are strongly recommended. Immunocytochemistry is mandatory for the diagnosis and a large antibodies panel is needed as differential diagnosis includes many different neoplasms. FISH may be useful to evaluate ALK rearrangements. When properly managed, cytology can lead to a reliable final diagnosis of ALCL.

Comparative Evaluation of Diagnostic Efficacy of Cell Block Versus Aspiration Cytology

Introduction: Fine-needle aspiration cytology (FNAC) has certain disadvantages despite being the most commonly used procedure in the initial diagnosis of any swelling. In such cases, a cell block (CB) study can be a valuable adjunct to smears for establishing a more definitive cytopathological diagnosis. Therefore, this study was conducted to evaluate the efficacy of CB with FNAC and to compare the findings of the CB and FNAC with histopathology as the gold standard. Materials and Methods: The study was conducted in the department of pathology at our institute. All the cystic/solid lesions sent for fine-needle aspiration, which yielded sufficient material for the CB, were studied along with detailed clinical history. Results: Out of 66 cases of FNAC and CB, 35 cases were sent for histopathology. The mean age of the patients was 41.36 years, and female patients were more in number (73%). Benign lesions (71.4%) were more than malignant ones (29.6%). The CB section had more thyroid lesions (31%). The diagnostic accuracy of FNAC was found to be 94.28%, while that of CB was 97.14%. Conclusion: Although FNAC is the first line of investigation for mass lesions, and still, to make the best possible use of an aspirate, smears should be used together with CB preparation to provide the best possible morphological and histological diagnosis.

Molecular testing opportunities on cytology effusion specimens: the pre-analytic effects of various body fluid cytology preparation methods on RNA extraction quality and targeted sequencing.

RNA sequencing (RNAseq) analysis is emerging as a clinical research or diagnostic approach for cytologic samples, but there is need for formal comparison of different sample preparation methods in the cytology laboratory to identify which pre-analytic methods could provide alternatives to formalin-fixed paraffin-embedded (FFPE) sections. We prepared 13 malignant effusions (metastatic estrogen receptor-positive breast cancer) in the cytology laboratory using 6 routine cytologic methods: FFPE cell block, Carnoy's solution, 95% ethanol (EtOH), air-dried and Diff-Quik, ThinPrep, and SurePath preparations. Measurements of RNA quality, expression of 2 multigene expression signatures, molecular subtype, and 4 common activating mutation sites in each preparation were compared with fresh frozen (FF) cell pellet in RNA preservative using distribution of fragment length and concordance correlation coefficient (CCC). The fraction of RNA fragments measuring 200 bases or more (DV200) were 24% higher from cytospins fixed in Carnoy's solution or 95% EtOH than DV200 from FFPE cell blocks. SurePath samples failed RNAseq quality control. There was high concordance of gene expression measurements with FF samples using cytospins fixed in Carnoy's solution, 95% EtOH, Diff-Quik (CCC = 0.829, 0.812, 0.760, respectively), or ThinPrep (CCC = 0.736), but lower using FFPE cell block (CCC = 0.564). The proportion of mutant transcripts was concordant between FF and any cytologic preparation methods. Cytospin preparations fixed with Carnoy's or 95% ETOH then Papanicolaou stained produced RNAseq results that were equivalent to FF samples and superior to FFPE cell block sections.

The utility of claudin-4 versus MOC-31 and Ber-EP4 in the diagnosis of metastatic carcinoma in cytology specimens.

Claudin-4 is a sensitive and specific marker for carcinoma in effusion cytology. The authors examined the diagnostic use of claudin-4 versus MOC-31 and Ber-EP4 by comparing their sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) in differentiating carcinoma from mesothelioma and benign/mesothelial hyperplasia in effusion specimens. This retrospective study comprised a cohort of 229 cytology specimens, including 211 effusion fluid and 18 fine-needle aspiration specimens. Cytologic categories included 134 carcinoma, 28 mesothelioma, 46 indefinite (suspicious and atypical), and 21 benign. Cell block sections were stained for claudin-4 and compared with those previously stained for MOC-31 and Ber-EP4. Indefinite cases were further reclassified based on clinical and pathologic findings into benign (26 cases), mesothelioma (11 cases), and carcinoma (nine cases). None of the mesotheliomas (0/39) or benign effusions (0/47) were positive for claudin-4, whereas 134 of the 143 carcinoma specimens were positive. Compared to MOC-31 and Ber-EP4, claudin-4 had the highest specificity and PPV (100% for each), followed by Ber-EP4. Claudin-4 showed high sensitivity (93.7%), albeit lower than MOC-31. MOC-31 had the lowest specificity and PPV but the highest sensitivity and NPV. Ber-EP4 had the lowest sensitivity (91.6%). Claudin-4 can be used as a single marker for carcinoma with high sensitivity and superior specificity compared with MOC-31 and Ber-EP4. Mesothelial lineage can be ruled out when claudin-4 is positive. In equivocal cytology samples with few scattered cells of interest, a panel of claudin-4 and Ber-EP4 results in the highest combined sensitivity and specificity.

A novel method for making cell blocks with higher cellular yield.

Cytopathology is an important part of pathology that is used to diagnose disease on the cellular level. The application of the cell block (CB) technique plays a vital role in cytological diagnosis, as blocks and slides can be further used for special stains, immunohistochemistry (IHC), and molecular pathological analysis. Several methods for making CBs have been reported, but their procedures and cellular yield are still deemed unsatisfactory. In this article, we used gellan gum (GG) as an adjuvant for CBs, which resulted in higher cellular yield with simpler procedures. CBs were prepared by using GG, copper sulfate, plasma/thrombin, or pregelatinized starch methods. The procedures of each of these four methods were then compared. CB sections were stained with hematoxylin and eosin (H&E), and the background and morphological features seen by H&E staining were compared. A preliminary IHC and fluorescence in situ hybridization (FISH) study was performed using cytology specimens from elevenand five cases, respectively. The expression of immunocomplex by IHC and the molecular signals detected by FISH were compared in CB sections made by the four methods and a section derived from the biopsy specimen block from the same patient. Feulgen staining, Alcian blue staining, and Masson trichrome staining were performed on the CB sections from 3 cases of pleural fluid. The cellular yield of CB sections from 83 cases according to the four methods was compared using NDP analysis software. The results demonstrated that sections derived from CBs made with GG had a clear background and good morphological features by H&E staining. The expression of immunocomplex by IHC and the molecular signals of FISH detection in the sections from CBs made by GG were accurately located just as those in biopsy sections from the same patient. The DNA, acidic mucus, and fibrin could be clearly identified through special stains in the CB sections. The procedures involved in the GG method were easily controllable and the coagulated gel increased the ease by which the CB was embedded and sectioned. Specifically, sections from CBs made by the GG method contained higher cellular yield because cells could be concentrated on the bottom of the gel after centrifugation. This novel method for making CBs is a practical, simple method that can result in higher cellular yield. This method is therefore worth promoting in clinical applications.