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BACKGROUND Inconclusive cytomorphology often results due to failure to distinguish between adenocarcinoma cells from benign, reactive, atypical mesothelial cells in effusion specimens. To resolve such dilemmas, auxiliary techniques like immunohistochemistry were utilised to reach a definitive diagnosis for better treatment and management of patients. We wanted to compare cytodiagnosis achieved on cell block preparations with the cytodiagnosis on conventional smear and perform immunohistochemistry for epithelial membrane antigen (EMA), calretinin, desmin, vimentin and E-cadherin on cell block preparation of the fluids in cases of indistinguishable cytomorphology of adenocarcinoma and reactive, atypical, and benign mesothelial hyperplasia. METHODS The immunohistochemical markers namely EMA, calretinin, vimentin, desmin and Ecadherin were applied on cell blocks employing streptavidin-biotin method. Immunohistochemistry was interpreted by giving scores to the percentage of stained cells. RESULTS EMA and E-cadherin had 100 % sensitivity in diagnosing adenocarcinoma whereas calretinin, vimentin and desmin were 100 % sensitive in diagnosing reactive, atypical mesothelial carcinoma on the cell block preparations. CONCLUSIONS Immunocytochemistry of fluid should be carried out on the cell block preparation where cytological diagnosis on conventional smear and cell block fails to detect malignant cells in the preparation. KEY WORDS Cell Block, Adenocarcinoma, Mesothelial Cells, Immunohistochemistry, EMA, Calretinin, Vimentin, Desmin, E-Cadherin

Background: Programmed death ligand-1 (PD-L1) assessed by immunohistochemistry (IHC) is used as biomarker for pembrolizumab therapy in advanced stage lung cancer patients. However, data permitting direct performance comparison between cytology and surgical specimen types are limited since both specimens from a single tumor site are infrequently available. In addition, alcohol fixation used with cytology specimens requires technical validation of the PD-L1 IHC assay before clinical use. We here report our experience with implementation of the PD-L1 22C3 IHC pharmDxTM assay for cytologic samples at a large tertiary cancer center. Study Design: Archival formalin-fixed (FF), paraffin-embedded cell blocks (CBs) and subsequent lung tumor resections (LTRs) from the same anatomical site were used for a direct comparison of PD-L1 tumor proportion scores (TPSs). TPS values were independently determined by one surgical lung pathologist and two cytopathologists blinded to the specimen pairs. An interim analysis was performed to facilitate the pooling of expertise among observers. After PD-L1 22C3 IHC pharmDxTM implementation for FF cytology specimens, dual-processed samples were used for a prospective technical validation of CytoLyt® prefixation (CF). Digital image analysis was performed for a subset of dual-processed specimens. Results: Eighty-one CBs and LTRs were included for comparison of the specimen types. PD-L1 assessment in CBs had an accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of 88.9/72.8, 66.7/73.5, 95.2/72.3, 80.0/65.8, and 90.9/79.1% for the ≥50/≥1% cutoff, respectively. The intraclass correlation coefficient was 0.84 (95% confidence interval [CI]: 0.76, 0.90), and it improved after interim analysis (before: 0.79 and after: 0.92). The overall concordance between CF and FF for the categories defined by the ≥50/≥1% cutoff values was 90.4% (95% CI: 79.0, 96.8). Similar assay performance was confirmed by digital analysis. Conclusions: PD-L1 22C3 IHC pharmDxTM shows good reliability if used with CB preparations. CF does not impact assay results significantly. Clinical validation with outcome data is needed, and digital methods of assessment should be further investigated.

Objective Primary retroperitoneal involvement of lymphoproliferative disorders is rare. Diffuse large B cell lymphoma (DLBCL) in the retroperitoneum has been scarcely reported and the diagnostic workup is challenging due to difficulties in access for tissue acquisition. Materials and methods A 73-year-old female presented with epigastric pain and nausea. A computed tomography scan revealed retroperitoneal lymphadenopathy. An EUS-FNA was performed and a cytological diagnosis of lymphomatous disorder was made on direct smears .A panel of immunocytochemical markers was applied on cell block preparations and revealed a EBV related DLBCL (CD20 positive, PAX-5 positive, CD3 negative, MUM-1 positive, BCL-2 positive, BCL-6 positive, CD10 positive, MIB-1 positive, and LMP-1 positive). Conclusion Our case illustrates the utility of EUS-FNA in the work-up of retroperitoneal lymphadenopathy and the importance of cell block processing in the diagnostic approach of EBV related DLBCL.

Background The identification of BRAF mutations in thyroid cancer has prognostic and therapeutic implications. Although the gold standard for identifying BRAF mutations is molecular testing, the ability to perform BRAF p.V600E immunostaining on fine-needle aspiration (FNA) samples can facilitate the rapid triaging of patients to treatment options. Methods A total of 50 thyroid carcinoma FNA samples, including papillary (29 samples), poorly differentiated (10 samples), anaplastic (9 samples), and Hurthle cell (2 samples) carcinomas, with a known BRAF p.V600E mutation status were selected for the current study. Immunostaining was performed on smears and cell block sections using an anti-BRAF p.V600E antibody (clone VE1). The results were compared with the known mutation status obtained by molecular testing and/or immunostaining of surgical pathology material from the same patient. Results Of the total of 50 cases, 26 cases had smears available for the evaluation of BRAF p.V600E immunostaining; positive immunostaining was noted in 16 samples and negative immunostaining was noted in 4 samples, whereas 6 cases were equivocal. Of the 34 cases for which cell blocks were available for evaluation, BRAF p.V600E immunostaining was positive in 17 cases, negative in 16 cases, and equivocal in 1 case. The overall sensitivity and specificity of BRAF p.V600E immunostaining on the cell block preparation was 94.4% and 100%, respectively, whereas for the smears it was 80% and 63.6%, respectively. Conclusions BRAF p.V600E immunostaining can be performed reliably on thyroid FNA cell block preparations. However, false-positive results on direct smears limit their utility and therefore need to be interpreted with caution. Cancer Cytopathol 2018;126:406-13. © 2018 American Cancer Society.

Studies using the cell-block technique for bone marrow (BM) analysis are limited in the veterinary literature. This work assessed whether the histopathological analysis of canine BM was feasible using cell-block cytoinclusions prepared from fine-needle sternal aspirate samples. Eight clinically healthy young-to-middle-aged dogs underwent both fine-needle sternal aspiration for BM cell-block (BM-Cb) processing and iliac-crest BM core biopsy (BM-B). Histopathologic parameters were compared between the 2 methods. There were no statistically significant histopathological differences between hematopoietic tissue areas (P = .6294) in the BM-Cb and BM-B sections, and they had similar microscopic characteristics and microarchitecture. Cellularity and reticulin-fiber staining were equivalent in the BM-Cb and BM-B preparations in 87.5% (7/8) and 100% (8/8) of the sections, respectively. However, the quantitative results of the megakaryocytic series differed between BM-Cb and BM-B in 37.5% (3/8) of the sections, and the myeloid:erythroid (M:E) ratios differed between the 2 methods in 25% (2/8). These preliminary data indicate that cell-block preparations made from sternal fine-needle aspiration samples warrant continued evaluation in a larger number of animals, including those with various diseases affecting the bone marrow.

Introduction The diagnosis of pancreatic ductal adenocarcinoma (PDA) on endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) material is often challenging. An immunohistochemical (IHC) panel may help establish the diagnosis of PDA in cases limited by sample size or ambiguous cytology. S100P, IMP3, and SMAD4 are 3 IHC markers that have shown promise as individual markers for PDA that have never been tested together as a panel. In this study, we evaluated the individual and combined efficacy of S100P, IMP3, and SMAD4 for the detection of PDA. Materials and Methods S100P, IMP3, and SMAD4 IHC staining was performed on cell blocks (CBs) procured from pancreatic EUS-FNA procedures. The cohort included CBs that were diagnostic for PDA (n = 35), suspicious but nondiagnostic for PDA (n = 2), as well as CBs with benign pancreatic ductal epithelium (n = 12) and benign reactive pancreatic ductal epithelium (n = 18). A positive result for IMP3 and S100P was defined as moderate or strong staining of >10% of ductal cells. Complete lack of SMAD4 nuclear staining was considered a positive result—any nuclear SMAD4 staining was considered a negative result. Results Two and 3 IHC marker panels were almost always more specific than individual IHC markers. Positivity for at least 2 of 3 IHC markers was a sensitive (91.89%) and highly specific (100%) marker of PDA. Conclusions The 3 IHC marker panel composed of S100P, IMP3, and SMAD4 is highly specific for PDA. Future studies should evaluate efficacy in a cohort with more atypical and suspicious cases.

Background: Cell Block (CB) procedures have now become an established part of cytological diagnostics because of its pivotal role in diagnosis and ancillary studies. Hence the present study was undertaken to emphasize the role of CB technique over Conventional Smear (CS) in serous effusions and to compare the Plasma-Thrombin (PT) block to Formalin Method block (FM) in assessment of morphological preservation and cellularity. Aim: To obtain simple , cost effective and ideal CB preparation where in maximal number of cells are displayed within a small area Methods: The sample was divided into three Parts(A,B,C). After centrifugation of all three parts of sample at 3000rpm for 15min – Part A sediment was used to prepare two CS for Papanicolaou (PAP) and May Grunwald Giemsa(MGG) stains. Part B sediment was subjected for 1hr and 24hr fixation in 1:1 solution of 5ml ethylalcohol and 10% formalin. To the Part C sediment 2drops of finger prick plain blood was added, mixed well and allowed to clot. The sediment of Part B and the clot of Part C were then processed for paraffin embedding. Result: 110 fresh effusion samples were evaluated for cellularity retention of architectural patterns and volume of background. FM block’s were inconclusive in 12 cases due to low cellularity. PT block’s were all evaluable with best preservation of architecture and pale background. Conclusion: The CB technique revealed better architectural patterns and increased the sensitivity of cytodiagnosis. PT block’s had sufficient to abundant cellularity with evenly distributed cells in small area. PT preparation is simple and cost effective. DOI: 10.21276/APALM.1432

Objective Atypical squamous cells of undetermined significance (ASCUS) and atypical glandular cells (AGC) reflect cellular abnormalities insufficient for clear diagnosis. We used cell pellets obtained from liquid-based cytology (LBC) to prepare cell blocks (CB) and clarify the initial diagnosis of ASCUS and AGC. Study Design A total of 393 CBs with initial diagnosis of ASCUS or AGC were processed. Of those, 305 of the ASCUS and 20 of the AGC had adequate specimens. We compared results of CBs prepared from ASCUS and AGC to determine which had higher frequencies of higher-grade lesions. Results A majority of specimens (83%) were adequate for evaluation. Compared with the initial diagnosis, 14% (42/305) of ASCUS were diagnosed with low-grade squamous intraepithelial lesion (LSIL) in CB, while 10% (2/20) of AGC were diagnosed with LSIL or adenocarcinoma. No statistical relationship between the initial diagnosis of ASCUS and AGC and results of higher-grade lesions in CB is evident as determined by p value greater than 0.05 (p = 0.228). Conclusions CBs prepared from Liqui-PREP cell pellets are, in most cases, assessable and can be useful as an adjunctive test to help clarify the initial diagnosis of ASCUS and AGC. Diagn. Cytopathol. 2017;45:520–525. © 2017 Wiley Periodicals, Inc.

Myofibroblastoma (MFB) is a benign tumor of the mammary stroma with predominant myofibroblastic differention. The cytologic reports of MFB are very few in the available literature. From the cytodiagnostic point of view about 21 cases of MFB with cytological evaluation by fine-needle aspiration cytology (FNAC) have been encountered in the English-language literature: A 35-year-old woman presented with lump in the left breast. FNAC showed mild degree of pleomorphism with occasional groups with fibrous stroma and tumoral cells. A few benign epithelial cell groups were seen. Hematoxylin-eosin-stained sections of cell block preparation from the aspirate showed fascicles of spindle cells forming whorl structures. Three months later, excision biopsy was performed. The diagnosis was a classic variant of MFB. On immunohistochemical examination, sections were found to be highly positive for vimentin, CD34, and bcl- 2. In light of these findings, cell block material was retrospectively reviewed both morphologically and immunhistochemically. The findings of resection and cell block material were found to be very similar. MFB may cause a potential diagnostic pitfall while interpreting FNAC due to its wide differential diagnosis spectrum. We concluded that cytology and cell block findings complement each other. Diagn. Cytopathol. 2016;44:1064-1069. © 2016 Wiley Periodicals, Inc.

Objectives Programmed death-ligand 1 (PD-L1) is an emerging molecular target in anticancer therapy, most notably non–small cell lung cancers. PD-L1 expression in pancreatic adenocarcinomas (PDAs) on surgical specimens is highly variable, with 10% to 60% of tumors showing expression. PD-L1 expression in PDA on endoscopic ultrasound-guided fine needle aspirations (EUS-FNAs) has been rarely studied. Methods Formalin-fixed, paraffin embedded (FFPE) cell blocks (CBs) from 65 EUS-FNA samples of 55 patients, with a diagnosis of PDA, with at least 20% tumor cellularity were retrieved. The cell blocks were originally fixed in CytoRich fixative. Immunohistochemical staining (IHC) for PD-L1 was performed using the M365329-1 (22C3) clone according to the manufacturer’s approved protocol and optimized for the fixation method using appropriate controls. A combined positive score (CPS) defined per CAP guidelines as the total number of positive tumor cells and inflammatory cells as a percentage of the total number of tumor cells was assessed for each case and was grouped as 20. Results Twenty-five samples (38%) from 21 patients showed immunoreactivity to PD-L1, with 21 (32%) having a CPS of Conclusion Immunohistochemical analysis for PD-L1 is feasible on EUS-FNA CB samples when optimized and validated for the fixation method using appropriate controls. PD-L1 expression is seen in only a minority of PDAs, albeit with a very low CPS. The potential role of PD-L1 as a prognostic marker for disease progression needs further exploration.

Objectives: HER2 status of breast carcinoma is a powerful prognostic and predictive biomarker-particularly in the metastatic setting. Limited data is available regarding assessment of HER2 on cell block preparations (CBP). The primary objective of this study was to assess correlation between HER2 results obtained via immunohistochemistry (IHC) and fluorescence in-situ hybridization (FISH) in cases of metastatic breast carcinoma (MBC) on CBP. Secondary objectives included study of inter-observer variability in interpretation of HER2 on IHC, and concordance between HER2 results on CBP and formalin-fixed paraffin embedded material (FFPEM). Materials and Methods: Cases of MBC diagnosed on fine needle aspirates (FNA) with HER2 testing performed via IHC and FISH on CBP over 5 years (2010-2015) were reviewed. CBP material was fixed in an ethanol-based fixative (CytoRich Red Fixative system, BD). HER2 IHC was performed using polyclonal antibodies against Cerb-2 (Dako 0485). HER2 FISH testing was performed using the LSI HER2/neu/CEP17 probes (Vysis/Abbott Molecular Inc., Des Plaines, IL). Results: Seventeen cases (all female, median age: 59) were analyzed. 41% of CBP were products of bone FNA (7/17). Other sites included lymph node (3), lung (2), pleural fluid (2), liver (1), skeletal muscle (1) and mesentery (1). Median interval between diagnosis of primary carcinoma and FNA of metastasis was 5 years (range: 10 months-32 years). FISH was inconclusive due to suboptimal specimen quality in 2 cases. Correlation between IHC and FISH results was as follows: IHC 0/1+ (0/2; 0% amplification), IHC 2+ (2/12; 16.7% amplification) and IHC 3+ (0/1; 0% amplification). Inter-observer agreement of IHC scoring between 2 pathologists who independently reviewed IHC slides was fair (66.7% agreement, κ = 0.31). Comparison of HER2 results on CBP with FFPEM (primary carcinoma or metastasis) showed a high discordance and slight agreement (discordance rate = 37.5%; κ = 0.02). Conclusions: In this study, (a) 16.7% of MBC cases that scored 2+ on IHC showed amplification on FISH, (b) there was poor inter-observer agreement in HER2 scoring of IHC on CBP, and (c) there was high discordance between HER2 results obtained on CBP and FFPEM. Our results indicate that HER2 testing of MBC on CBP may be unreliable.

Evaluation of ER, PR and Her 2 are routinely performed on breast carcinomas. For accurate detection of these markers, compliance with the ASCO/CAP guidelines is recommended. Our previous study showed that alcohol fixation did not affect ER results when alcohol-fixed cell block (CB) sections were compared to formalin-fixed tissue sections, while PR and Her2 showed less concordance. The aim of this study was to evaluate and to compare ER, PR and Her2 IHC results on formalin-fixed CB sections to those observed on subsequent surgical (needle core or resection) specimens (SS). Fifty cases of formalin fixed CB samples obtained from primary (18%) and metastatic (82%) breast carcinomas were studied, all of which had subsequent SS available. ER, PR, and Her2 IHC studies were done on all samples and results were compared. ER results on formalin-fixed CB samples showed excellent correlation with SS (correlation coefficient cc = 0.82). While there was minimal improvement in PR results (cc = 0.433), Her2 detection did not improve by formalin fixation (cc = 0.439). Formalin fixation for CB preparations does not significantly improve the already good detection of ER positive breast tumors. The concordance rate in PR and IHC results between formalin-fixed CB and SS samples showed improvement as compared with the alcohol-fixed CB results. However, there was no improvement in detection of Her2 overexpression by using formalin fixation on cytology specimens.

BACKGROUND Cell block (CB) preparation during the endobronchial ultrasound-guided transbronchial fine-needle aspiration (EBUS-TBNA) procedure plays an important role in the diagnosis of lung cancer and recovery of cellular material for molecular characterization of the tumor. However, the efficiency of the conventional method of CB preparation is suboptimal.

Objective Recent studies have validated the use of cytologic materials to determine HER-2/neu status. Good concordance has been shown between results obtained by immunocytochemistry (ICC), immunohistochemistry (IHC), fluorescence in situ hybridization (FISH) on cytologic and surgical specimens. However, the utility of cytologic cell block material in determining HER-2/neu status has not been reported and is the subject of this study. Study Design HER-2/neu status was determined in 25 cases of primary or metastatic breast carcinoma by IHC and FISH. All cases were formalin-fixed, paraffin-embedded (FPPE) cell block preparations. ICC was performed using monoclonal antibodies TAB250 (Zymed) and CB11 (Novacastra Laboratories). FISH analysis was performed using the PathVysion HER-2 probe kit (Vysis, Inc.). Results of ICC and FISH were compared in each case. Results Of 25 cases studied, 17 showed no protein overexpression or amplification. Five cases showed protein overexpression and amplification. The remaining 3 cases showed 2+ staining intensity by ICC in 10, 20, and 50% of carcinoma cells, respectively, and all demonstrated lack of amplification. Conclusion Immunocytochemistry performed on FFPE cell block material is a reliable method for determining HER-2/neu status in cytologic specimens. We recommend routine preparation of FFPE cell block material in instances of suspected primary of metastatic breast carcinoma.

BACKGROUND Calretinin (CR) is a valuable marker in the immunohistochemical distinction between malignant mesothelioma (MM) and adenocarcinoma (ACA) in tissue sections. However, there is limited and conflicting data regarding the utility of CR in this differential diagnosis on cytologic material, especially cell block preparations. Also, the possible role of CR in the distinction of papillary serous borderline tumor (SBT) cells from reactive mesothelial cells in peritoneal washings has not been examined. METHODS Formalin-fixed paraffin-embedded cell block specimens of cytologic fluids, washings, and aspirates with a suspicious or positive cytologic diagnosis and a confirmed diagnosis of MM (29 cases), ACA (39 cases), and SBT (10 cases) were used for CR immunohistochemistry (IHC). RESULTS Moderate to strong staining in > 50% of tumor cells was noted in 26 of 29 (90%) MMs but in only 3 of 39 (8%) ACAs and 1 of 10 (10%) SBTs. Admixed reactive mesothelial cells (when present) were strongly positive in all fluid specimens, but the staining pattern of benign non-reactive mesothelial cells in washing specimens was less reliable. CONCLUSIONS CR is both a sensitive and specific marker of reactive and neoplastic mesothelial cells in cytologic cell block preparations and is thus useful in the differential diagnosis of MM and metastatic ACA in malignant effusions. However, CR IHC does not appear to allow definitive identification of SBT in peritoneal washings. Cancer (Cancer Cytopathol) 2000;90:312–9. © 2000 American Cancer Society.

OBJECTIVE: To evaluate the utility of immunohistochemical stains for desmin in discriminating mesothelial cells from adenocarcinoma in serous fluid cell block preparations. STUDY DESIGN: Cell block preparations from 22 cases (representing 18 patients) that were positive for carcinoma and 5 cases that were negative for malignancy were immunostained with an antibody to desmin. Positive staining was evaluated and scored semiquantitatively in both tumor cells and background mesothelial cells in the malignant cases and mesothelial cells in the negative controls. Staining was evaluated with a score of 0-3 for intensity and 0-5 for distribution. The sum of the two scores was recorded as the total score (TS). RESULTS: Mesothelial cells from all the carcinoma and benign cases stained with desmin (median TS = 5.5, range 4-8), typically strong in intensity and widespread in distribution. Positivity was observed in carcinoma cells in all cases, typically weak and focal (range 2-4). Using a total score of 4 as a cutoff for definitively positive staining, desmin staining was positive in mesothelial cells in 25/25 cases and carcinoma cells in 1/22 cases (P

Objective: Cervical cancer is one of the most common malignancies worldwide, yet it is preventable by population screening. In a previous study, we confirmed the feasibility of utilizing whole slide imaging (WSI) of cell block (CB) preparations to overcome the limitations of digitizing cytologic samples. In this study, we evaluated the accuracy of WSI in identifying various organisms and nonneoplastic findings. Study Design: A total of 335 WS images from Pap CB preparations were analyzed using the Aperio system. The test performance characteristics of ThinPrep (TP) and WSI samples were compared for adequacy, for the presence of bacterial vaginosis (BV), fungi, Trichomonas vaginalis (TV) and herpes simplex virus (HSV) and for nonneoplastic findings. Results: The WSI samples contained optimal material from all preparations. BV was diagnosed in 33 WSI versus 36 TP samples. Budding yeasts and/or pseudohyphal forms were noted in 18 WSI versus 19 TP samples. TV organisms (10 of 11 samples) and 1 HSV case were accurately identified in the WSI and TP samples. Squamous metaplasia, keratosis and reactive/reparative and inflammatory changes were easily identified by WSI. Conclusions: The concept of WSI from Pap CB preparations is potentially feasible for adoption. Digital remote web-based technology eliminates the need for an individual on site, saving time and resources.

We compared the results of smears to those of cytospin and cell block preparations from fine-needle aspirations to determine the cost effectiveness of each and to determine which should be routinely obtained. We reviewed 844 cases, 361 of which had both smears and cytospins, and 483 of which had both smears and cell blocks. Smears alone were diagnostic in 94% of cases (796/844 cases), cytospins alone diagnostic in 43% of cases (154/361 cases), and cell blocks alone diagnostic in 57% of cases (277/483 cases). Cytospins contributed additional information beyond that obtained from smears in 2% (7/361) and cell blocks in 12% (57/483) of cases. When smears were nondiagnostic, cytospins contributed additional information in 10% (2/21) of cases and cell blocks contributed additional information in 44% (12/27) of cases. The cost of providing a diagnosis from smear alone is $212, from cytospin alone is $352, and from cell block alone is $392. The cost for additional information established by cytospin is $7,736 and by cell block the cost is $1,906. Smears are superior to either cytospins or cell blocks in providing a diagnosis. It is not cost-effective to obtain either cytospins or cell blocks in addition to smears on all cases. However, it is cost-effective to obtain cell blocks when the immediate smear evaluation is nondiagnostic.

Objective To evaluate the utility of CD10 immunostaining on cell block preparations from pelvic washing cytology material obtained during laparoscopy in cases of pelvic endometriosis (PE). Study design Six premenopausal women presenting with ovarian masses underwent a laparoscopic procedure. In addition to routine cytospin preparations, cell blocks were prepared using the formalin-fixed, paraffin-embedded method from the pelvic washings in each case. Immunocytochemistry using monoclonal antibodies for cytokeratin (CK) 7, CK20, CD10, estrogen receptor (ER), progesterone receptor (PR) and CA125 was performed on sections from cell blocks using the streptavidin-biotin peroxidase complex. Results Clusters of epithelial cells (3 cases) and stromal cells (2 cases) were seen in a background rich in hemosiderin-laden macrophages and poorly preserved mesothelial cells on cytospin smears. CD10 and CK7 were consistently positive in the stromal and epithelial components, respectively, in all cases on cell block sections. Variable staining reactions were noted for ER, PR and CA125. Conclusion CD10 immunostaining is a useful ancillary method in the diagnosis of endometriosis. Its routine use on cell block preparations from pelvic washings in women undergoing a laparoscopic procedure is recommended.

Endobronchial ultrasound-guided transbronchial needle aspiration has demonstrated its accuracy in the diagnostic workup of enlarged mediastinal lymph nodes. In addition to conventional smears, the use of liquid-based cytology (LBC) and cell block preparations (CBP) has been introduced more recently. The aim of our study was to determine the performance of each of the different techniques, separately and combined, in terms of diagnostic yield and sensitivity. A total of 290 consecutive patients were included. The pathological examination was based on smear cytology, LBC, and CBP. Adequate sampling was defined by the presence of pathological material or lymphocytes. The global diagnostic yield was 82.7 % and the sensitivity was 89.1 %. The diagnostic yield was 72.8 % for smears, 78.8 % for LBC, and 69.9 % for CBP. The combination of smears with CBP significantly increased diagnostic yield (p = 0.01) and sensitivity (p = 0.006), but not the combination of smears with LBC (yield: p = 0.07; sensitivity: p = 0.13). The combination of the three techniques further increased yield (p = 0.007) and sensitivity (p = 0.006), compared with smears alone. CBP were more sensitive than smears for both diagnoses of carcinoma (p = 0.01) and granulomatous inflammation (p = 0.048). Conversely, LBC was less sensitive than smears for granulomatous inflammation (p = 0.004), but the difference was not significant for carcinoma (p = 0.42). CBP, as a complement to smears, increases diagnostic yield and sensitivity for both diagnoses of carcinoma and granulomatous inflammation. LBC, if used alone, increases the risk of a false-negative result.

Objective: To determine the value of calretinin and cytokeratin (CK) 5/6 in discriminating mesothelioma from adenocarcinoma in serous effusion specimens. Methods: A total of 101 recent, histologically or clinically confirmed malignant effusions with immunostained cell block preparations were reviewed. The cases consisted of 34 mesotheliomas and 67 adenocarcinomas. This included 17 ascitic fluid and 84 pleural fluid samples. The adenocarcinomas included metastatic carcinomas from the breast (12), lung (19), stomach (3), colon (1), pancreas (2), ovary (6) endometrium (1) and 23 histologically confirmed metastases from unknown primary sites. The cases were assessed as negative or positive (>5% of cells stained). The staining pattern was recorded as cytoplasmic, cell membrane, nuclear or cytoplasmic and nuclear staining. Results: Calretinin staining was present in 97% (33/34) of the mesothelioma cases with a majority of them showing both cytoplasmic and nuclear staining (29/33). Only 3% (2/67) of adenocarcinomas were positive for calretinin, one being a lung adenocarcinoma and the other an adenocarcinoma of unknown primary site in an ascitic fluid. Cytokeratin 5/6 staining was also present in 33/34 (97%) of mesothelioma cases. Six (9%) adenocarcinomas were positive, including metastases from the lung (1), breast (1), ovary (2) and unknown primary site (2). Four of the six adenocarcinoma cases positive for CK5/6 were in ascitic fluids. No cases of mesothelioma were negative for both calretinin and CK5/6. Only one adenocarcinoma case, (which was from unknown primary site in an ascitic fluid sample), was positive for both markers. Conclusions: The results confirm that calretinin and CK 5/6 are useful markers for mesothelioma in effusion specimens. CK5/6 staining may be less useful for peritoneal fluid specimens where metastatic adenocarcinomas may be more likely to express the antigen. Further study of ascitic/peritoneal specimens is warranted. However, positive staining, particularly for both antigens, is highly indicative of a mesothelial origin for cells. The two markers make a useful addition to EMA and the panel of adenocarcinoma markers routinely applied to effusion specimens.

Serous tumors of low malignant potential are uncommon in women under 30-years-old peritoneal washings play an important role in the diagnosis and prognosis of ovarian neoplasms. Accurate diagnosis of peritoneal washings is important in determining therapeutic regimens and in determining patient prognosis. In peritoneal washings, these tumors can be difficult to distinguish from reactive benign mesothelial cells. The cases of four women with borderline serous ovarian tumors, all of whom were under the age of 25, and had peritoneal washings which were positive for papillary tumors were reviewed.

AIMS: To review consecutive cell block preparations of cytological specimens in a large general hospital. METHODS: 50 cell blocks were made over an 18 month period in which about 1900 fine needle aspirations (FNAs) were performed. The aspirator was a cytologist or, for image guided FNAs, a radiologist with a cytologist at hand to collect the specimen. Forty eight cell blocks were from FNAs and two were from serous fluids. RESULTS: The cellularity of the cell blocks was inadequate in only four preparations. The main motive for making cell blocks was to obtain tissue for immunohistochemistry. This was performed on 28 cases and a total of 107 immunostained sections were produced. The most common diagnostic dilemma was between carcinoma and melanoma, and the second most common between carcinoma and lymphoma. Consequently cytokeratin, S-100, and LCA were the most frequently used antibodies. At least one of these three antibodies was positive in 17 cases. Five cases were immunostained only for prognostic breast markers. CONCLUSIONS: The use of cell block immunohistochemistry is a reliable and technically unsophisticated aid in the cytological examination of tumours other than lymphomas. Success depends on having highly experienced aspirators that reliably obtain sufficiently cellular material.

Background The development of high-throughput drug screening (HTS) using primary cultures provides a promising, clinically translatable approach to tailoring treatment strategies for patients with cancer. However, this has been challenging for solid tumors because of often limited amounts of tissue available. In most cases, in vitro expansion is required before HTS, which may lead to overgrowth and contamination by non-neoplastic cells. Methods In this study, hematoxylin and eosin staining and immunohistochemical staining were performed on 129 cytopathology cases from 95 patients. These cytopathology cases comprised cell block preparations derived from primary tumor specimens or patient-derived xenografts as part of a pediatric precision oncology trial. Cytopathology cases were compared with the morphology and immunohistochemical staining profile of the original tumor. Cases were reported as tumor cells present, equivocal, or tumor cells absent. The HTS results from cytopathologically validated cultures were incorporated into a multidisciplinary tumor board report issued to the treating clinician to guide clinical decision making. Results On cytopathologic examination, tumor cells were present in 77 of 129 cases (60%) and were absent in 38 of 129 cases (29%), whereas 14 of 129 cases (11%) were equivocal. Cultures that contained tumor cells resembled the tumors from which they were derived. Conclusions Cytopathologic examination of tumor cell block preparations is feasible and provides detailed morphologic characterization. Cytopathologic examination is essential for ensuring that samples submitted for HTS contain representative tumor cells and that in vitro drug sensitivity data are clinically translatable.

BACKGROUND: Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors of the gastrointestinal (GI) tract, and the majority contain KIT or PDGFRA activating mutations. Fine-needle aspiration biopsy (FNAB) is a valuable technique in the diagnosis of GIST and may allow for preoperative therapy with tyrosine kinase inhibitors (TKI). Because of the morphologic diversity of these tumors, routine diagnosis of GIST often relies on C-Kit immunohistochemical staining in addition to morphologic findings. However, up to 15% of GISTs are C-Kit negative. Antibodies with increased sensitivity and specificity for detection of C-Kit–negative GIST cases may be of value, especially because some of these cases may also benefit from TKI therapy. METHODS: Immunohistochemical staining for DOG-1, C-Kit (CD117) and protein kinase C theta (PKCθ) was performed on FNA cell-block preparations representing 30 GISTs, 17 leiomyosarcomas, 16 melanomas, 16 schwannomas, 11 adenoid cystic carcinomas, and 8 leiomyomas. RESULTS: DOG-1 was found to have 100% sensitivity and 100% specificity in diagnosis of GIST. C-Kit demonstrated 70% sensitivity and 76% specificity, and PKCθ showed 40% sensitivity and 86% specificity. When only spindle-cell neoplasms were considered (adenoid cystic carcinomas excluded), the specificity of C-Kit increased to 89%. Of interest, all C-Kit–negative cases showed DOG-1 positivity. CONCLUSIONS: DOG-1 was the most sensitive and specific of the 3 markers for the diagnosis of GIST in cell-block preparations and may be of particular use in the diagnosis of C-Kit–negative GIST. Cancer (Cancer Cytopathol) 2011;. © 2011 American Cancer Society

Background The optimal volume of pleural fluid to diagnose a malignant effusion is unknown. Our study was designed to demonstrate if a minimum pleural fluid volume (10 mL) is equivalent to a large volume thoracentesis to make a cytopathologic diagnosis of malignancy. Methods A total of 121 thoracentesis samples were obtained from 102 patients with suspected or known malignant effusions. Pleural fluid was collected in three aliquots for cytologic examination (10 mL, 60 mL, ≥ 150 mL). The pathologist was blinded to patient identifiers and aliquot volume. Sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) were calculated for each volume for the diagnosis of malignancy. Results Pleural malignancy was diagnosed in 90 patient encounters (74.4%). For direct smear/cytospin, there was increased sensitivity and NPV for 60 mL ( P = .0058 and P = .045, respectively) and for ≥ 150 mL ( P P = .009, respectively) compared with 10 mL. For combined direct smear/cytospin and cell block preparations, statistical significance for sensitivity and NPV existed only between the 10 mL and ≥ 150 mL specimens ( P = .0099 and P = .033, respectively). No statistical difference existed for specificity or PPV for any aliquot volume. Conclusions The sensitivity for diagnosis of pleural malignancy is dependent on the pleural fluid volume extracted during thoracentesis. Volumes of 10 mL do not perform as well as larger volumes. When both direct smear/cytospin and cell block preparations are used, we recommend ≥ 150 mL, whereas when only direct smear/cytospin is used, 60 mL is adequate for the diagnosis a malignant pleural effusion.

Objective: To assess the diagnostic value of clot examination for satisfactory processing and confirmation of malignancy in serous effusions in routine cytological evaluation and compare the results with those of conventional smear and cell block preparations. Methodology: Body cavity fluids (n = 600) received in our laboratory were processed according to a pre-designed protocol for the study as follows: Day1: on receipt of the specimen, smears were made and a cell block was prepared from the sediment. Day2: after overnight sample storage of the remaining specimen at 2–8 °C all fluids were examined for the presence of a clot at the bottom of the container. Fluids in which clot had formed were fixed in formalin. The clot was then placed on a lens paper, wrapped and processed routinely. Diagnostic yields were compared. Results: In this study, we included 600 cases of serous fluids from pleural, pericardial and peritoneal effusions. In 73% (n = 437) of samples, clot formation was seen, while in 27%, (n = 163) no clot had formed. Routine smear and cell block preparations showed malignant cells in 9.6% (n = 42). However, with the addition of the clot preparation, the number of cases in which atypical/malignant cells were seen increased from 42 to 85 (19.4%), with a P

Context.—Immunohistochemical staining for cytokeratin 19 (CK-19) is a useful ancillary technique for diagnosing papillary thyroid carcinoma (papillary carcinoma) in histologic specimens. Although similar results have been obtained on aspirate smears, to our knowledge the utility of CK-19 immunolocalization in cell block preparations as an adjunct to fine-needle aspiration diagnosis of papillary carcinoma has not been examined. Objective.—The purpose of this study was to determine whether CK-19 immunostaining of cell block preparations of thyroid aspirates is a useful ancillary technique for diagnosing papillary carcinoma. Materials and Methods.—Using a monoclonal antibody to CK-19 and a standard avidin-biotin complex technique, immunostaining was performed on paraffin-embedded cell blocks of 57 cases with the following cytologic diagnoses: (a) papillary carcinoma (20 cases); (b) atypical cytology, cannot exclude papillary carcinoma (19 cases); and (c) nonneoplastic thyroid (18 cases). The staining reaction in each case was graded on the basis of percentage of epithelial cells stained (1+, 50). Tissue follow-up was available in all cases. Results.—Nineteen (95%) of 20 cases with an unequivocal diagnosis of papillary carcinoma were positive for CK-19 (3+). Tissue follow-up confirmed papillary carcinoma in all 20 cases. Of the 19 cases with a diagnosis of atypical cytology, cannot exclude papillary carcinoma, 7 (37%) cases displayed 3+ immunostaining and subsequent excision confirmed papillary carcinoma in all 7 cases. The remaining 12 cases with 1+ immunostaining included surgically confirmed goiter (6 cases), adenoma (2 cases), lymphocytic thyroiditis (3 cases), and papillary carcinoma (1 case). The follicular cells in 18 cases with a cytologic diagnosis of nonneoplastic thyroid showed 1+ immunostaining. Histologic follow-up of these cases confirmed the nonneoplastic cytologic diagnoses. Conclusions.—Cytokeratin 19 immunostaining of cell block preparations of thyroid aspirates serves as a useful tool for the diagnosis of papillary carcinoma. Strong immunostaining (3+) for CK-19 aids in accurate diagnosis of malignancy in cytomorphologically equivocal cases of papillary carcinoma.

BACKGROUND It has been shown that detection of the Wilms tumor susceptibility gene 1 protein (WT1) has diagnostic utility in the distinction of mesothelioma from adenocarcinoma in tissue sections of pleural tumors. This immunohistochemical study evaluates the effectiveness of WT1 as a marker for malignant mesothelioma in paraffin sections of cell block preparations derived from effusion specimens. METHODS The authors evaluated 111 cell blocks for WT1 immunoreactivity, including 14 mesotheliomas and 97 metastatic adenocarcinomas from various sites. RESULTS Nuclear reactivity for WT1 was observed in all samples of mesothelioma. However, only 22 of 97 samples (23%) of metastatic adenocarcinoma, nearly all of which were of ovarian origin (91%), exhibited nuclear reactivity for WT1. In 14 other samples (most of pulmonary derivation), WT1 staining restricted to the cytoplasm was observed for some tumor cells and was regarded as nonspecific. CONCLUSIONS Based on this staining profile, WT1 represents an effective marker for mesotheliomas in cell block preparations and can aid in its distinction from pulmonary adenocarcinoma. In assessment of effusion specimens with metastatic carcinoma, nuclear reactivity for WT1 is highly suggestive of an ovary primary tumor. Cancer (Cancer Cytopathol) 2002;96:000–000. © 2002 American Cancer Society.

Background Palpable thyroid nodules are present in 4-7% of general population and Fine Needle Aspiration (FNA) is now accepted by endocrinologists and thyroid surgeons as a safe, simple and cost effective procedure for evaluating a thyroid nodule. The obtained sample can be spread directly on slides, processed as cell block preparations or prepared as liquid base smears. Liquid base method has been recently accepted due to its shorter preparation time and better preservation of nuclear details. The aim of this study is to compare the diagnostic results of two commonly used methods: Liquid Base Preparation and Cell Block Preparation in evaluation of thyroid nodules. Methods The samples were taken from 100 patients with a solitary nodule or a prominent nodule on a multinodular goiter background (excluding hot nodules). The obtained samples were used to prepare conventional smears (CS), Cell Block Preparations (CBP) and Liquid Base Preparations (LBP). The slides were studied by two pathologists, considering the following parameters: Cellularity, Colloid, Lymphocytes/Plasma cells and Macrophages. Results 87% of cases revealed informative results in LBP method while in the same group of patients only 69% of samples were informative after processing by CBP method. Sensitivity and specificity of both methods compared with the conventional smears and with each other and it is concluded that LBP is a reliable method for evaluating of a thyroid nodule. Other studies also show the same results. Conclusion The liquid base method should be trusted due to its easier procedure, cleaner slide background, its higher specificity and higher diagnostic yields. It can be used instead of CBP and in association with CS to increase the accuracy of evaluation of thyroid nodules.

BACKGROUND: Fine needle aspiration biopsy (FNAB) affords a less expensive, less morbid approach to masses within the complex anatomy of the mediastinum as opposed to surgical biopsy. Given the current state of computed tomography guidance and the available cell block preparations and ancillary studies, definitive diagnosis of mediastinal tumors is possible. CASE: A 19-year-old male presented with weight loss and muscle weakness. Computed tomography revealed an anterior superior mediastinal mass with attachment to the posterior sternum and anterior aorta. FNAB yielded hyperchromatic cells with densely clumped chromatin and prominent nucleoli. These were present as single cells and clusters. Cell block preparations were studied with immunoperoxidase methods and were strongly positive for chromogranin and glucagon, supporting the diagnosis of carcinoid tumor. Surgical excision yielded a 7-cm, unencapsulated, red-brown tumor with medium-sized cells with oval to round nuclei, scant and granular cytoplasm and coarse salt and pepper chromatin with prominent nucleoli. The cells were arranged in islands and bands and were associated with prominent capillaries and dense, collagenous septae. Immunoperoxidase and electron microscopy demonstrated numerous intracytoplasmic, nonspecific neuroplasmic, nonspecific neurosecretory granules and positivity for somatostatin, synaptophysin, cytokeratin and chromogranin. CONCLUSION: FNAB affords an accurate and timely diagnosis of an anterior mediastinal tumor without the necessity for open biopsy and also offers accurate surgical planning and decreased morbidity.

Background: Amyloidosis is menacingly increasing medical problem in aging population across globe. Its clinical presentation is varied. Its laboratory diagnosis often requires biopsy material. The fine needle aspiration cytology (FNAC, FNAB) offers dependable diagnostic alternative to cumbersome biopsy. Present protocol describes the FNAC of abdominal pad of fat as surrogate site for diagnosis of senile systemic amyloidosis avoiding biopsy other known sites. Aim: To study diagnostic accuracy of subcutaneous abdominal fat tissue fine needle aspiration cytology/biopsy for detecting systemic (senile) amyloidosis and its utility in clinical practice. Objectives: To diagnose systemic amyloidosis (senile) by fine needle aspiration cytology/biopsy of abdominal fat pad on crush smears of aspirates and cell blocks. To correlate the diagnosis of deposits of amyloid with the clinical manifestations in specific and non specific clinical manifestations of amyloidosis. To know the sensitivity and specificity of the diagnosis of amyloid deposition on fine needle aspiration cytology/biopsy of abdominal fat pad in comparison to the results of cell block preparations. Methodology: A prospective study carried out to compare results of FNAC of abdominal pad of fat with paraffin embedded cell block in diagnosis of amyloidosis in suspected cases of cases of senile systemic amyloidosis. Technical adopted methods to be used are regular tissue stains, congo red stain and polarized microscopy. Expected Results: It is expected that results of study will establish FNAC of abdominal pad of fat as dependable office diagnostic procedure that would avoid complicated biopsy procedures of gastrointestinal tissue, skin, bone marrow and others for senile systemic amyloidosis.

We compared the diagnostic performances of conventional smears and cell block preparations of tissue samples obtained with endobronchial ultrasound-guided transbronchial needle aspiration. We retrospectively analysed 451 patients (926 lymph nodes) who had undergone endobronchial ultrasound and for whom both smears and cell blocks were available and compared the diagnostic performances of these techniques when used alone and combined. Cell block preparations showed higher diagnostic performance over smears, but the combination was superior to either alone. The combination of smear and cell block techniques achieved a sensitivity, specificity and positive and negative predictive values of 92.5, 100, 100, 97.7 and 99.4, 95.0, 98.6, and 97.9 % for malignant and benign diseases, respectively. We recommend cell block preparations during endobronchial ultrasound-guided transbronchial needle aspiration.

Eighty consecutive gynecologic specimens obtained with the Cavitron Ultrasonic Surgical Aspirator (CUSA) were evaluated pathologically. Fifty specimens were obtained during intraabdominal tumor debulking and thirty resulted from ablation of lower genital tract lesions. In 98% of intraabdominal specimens and in 93% of patients with a history of lower genital tract lesions, the CUSA material permitted an accurate diagnosis. Although artifacts related to cellular thermal injury were ubiquitous, nearly all cases were interpretable with a combination of cytologic (smear, Cytospin, Millipore filter) and histologic (cell block) preparations. Squamous intraepithelial lesions (SILs) of the lower genital tract were better preserved in cell block preparations, whereas intraabdominal adenocarcinomas were readily diagnosed by both cytologic and histologic techniques. Accurate grading of SILs and exclusion of invasion were difficult in some cell blocks due to the fragmented and superficial nature of the samples. Cytologic preparations of lower genital tract lesions often consisted of thick uninterpretable fragments and degenerated single cells that contributed little to the evaluation of SILs. We conclude that examination of CUSA specimens confirmed the surgical removal of pathologic tissue in 96% of cases, but an exact diagnosis of SILs was not possible in all cases.

Background: Early detection of pancreatic adenocarcinomas is essential for improving survival. In this regard, endoscopic ultrasound-guided fine-needle aspiration cytology (EUS-FNAC) has established itself as the method of choice for its ability to target lesions smaller than those which could be targeted by the traditional imaging methods like transabdominal ultrasound. Identifying these tumors correctly on FNA may be challenging because pancreatic adenocarcinomas may show a wide range of morphological features and the presence of contaminants from the gastrointestinal tract may show up as potential pitfalls. This study presents detailed cytomorphological analyses of 59 cases reported as pancreatic adenocarcinomas on smears and cell blocks. The clinical and histopathology follow-up data wherever available have also been presented. Materials and Methods: EUS-FNAC smears and cell blocks from cases reported as pancreatic adenocarcinomas were retrospectively evaluated with individual assessments of a range of features related to cellularity, cellular arrangement, cytoplasmic qualities, and nuclear features. Aspirates from peripancreatic lymph nodes, histopathology sections, and clinical records were reviewed wherever available. Results: Nonneoplastic cells like pancreatic ductal cells and acinar cells, duodenal, and gastric epithelia were detected along with neoplastic cells showing a wide range of variations in different cytomorphological characters. Often, a mixture of features was noted in the same case. Cell block preparations served as useful adjuncts since they made it possible to render unequivocal diagnoses of malignancies in cases where smears were hypocellular. Conclusion: The study creates a useful knowledge base of cytomorphological features of pancreatic adenocarcinomas.

CD138 (Syndecan-1) is a transmembrane heparan sulfate proteoglycan present on the surface of plasma cells and epithelial cells. CD138 is also expressed in some hematopoietic neoplasms and has recently been observed in carcinomas. We characterized CD138 expression in cell-block preparations of fluids/effusions, focusing on the distinction between carcinoma and mesothelioma. One hundred formalin-fixed, paraffin-embedded cell-block sections of fluids/effusions consisting of 58 metastatic carcinomas, 24 mesotheliomas, 11 reactive mesothelial cell proliferations, 3 lymphomas, 3 metastatic sarcomas, and 1 metastatic melanoma were stained with a monoclonal antibody against CD138. CD138 staining was observed in 32/58 (55%) metastatic carcinomas and 2/24 (8%) mesotheliomas; all reactive mesothelial cells, lymphomas, sarcomas, and melanoma were negative. CD138 is a highly specific marker in the differential diagnosis of carcinoma vs. mesothelioma. Distinct membranous staining without background staining of most inflammatory cells makes CD138 an ideal marker for cell-block preparations of fluids/effusions. It should be an integral component of the epithelial-mesothelial antibody panel.

Angiomyolipoma is a benign mesenchymal lesion that occurs most commonly in the kidney. Its occurrence in the liver is relatively rare. We report two cases of hepatic angiomyolipoma diagnosed by ultrasound-guided, needle aspiration biopsy. One of the patients was a previously healthy 62-yr-old woman who presented with a hepatic mass incidentally during a healthy examination. The other patient was a 67-yr-old man, a victim of chronic hepatitis C, who was found to have a hepatic tumor in the right lobe during regular follow-up. Cytologic preparations of the two hepatic masses showed some mature adipocytes admixed with clusters of variable-sized mesenchyme-like cells with fibrillar cytoplasm and indistinct cytoplasmic borders. Some of the cells were round to oval and others were spindle shaped with oval, cigar-shaped or elongated nuclei. The nuclear chromatin was fine and some cells showed round nucleoli. No thick-walled blood vessels were noted in the cytological smears. In the cell block preparations, a mixture of thick-walled blood vessels, mature adipose tissue, and bundles of variable-sized smooth muscle cells were noted. The spindle or epithelioid smooth muscle cells were positive for vimentin, α-smooth muscle actin, and human melanoma black (HMB)-45 but negative for desmin and S100 protein in immunohistochemical stains. The purpose of the current study is to describe cytological features of this lesion with differential diagnosis because pathologists may be called on to render a diagnosis on needle aspiration. HMB-45 has been proved to be a sensitive marker for the smooth muscle component of angiomyolipoma. Cell block preparations assisted with immunohistochemical staining should be emphasized for definite diagnosis. Although a surgical procedure may still be necessary once a diagnosis of angiomyolipoma is made, treatment may be tailored for a less aggressive procedure than for malignant hepatic nodules. Diagn. Cytopathol. 2004;31:263–266. © 2004 Wiley-Liss, Inc.

BACKGROUND Cell blocks can be prepared from residual thin-layer cervicovaginal (ThinPrep) material and can be used in immunohistochemical staining assays for p16INK4a and Ki-67, which are surrogate markers related to human papillomavirus infection and cell proliferation, respectively. The objectives of the current study were 1) to investigate the feasibility and the role of cell block preparations in identifying significant neoplastic and preneoplastic lesions of the uterine cervix and 2) to assess the feasibility of using p16INK4a and Ki-67 immunohistochemical staining patterns on cell blocks to identify significant preneoplastic cervical lesions. METHODS Cervicovaginal cytology specimens from 85 patients were analyzed. Cytologic diagnoses based on ThinPrep Papanicolaou test results were as follows: squamous cell carcinoma was diagnosed in 3 specimens, high-grade squamous intraepithelial lesions (HSIL) were diagnosed in 27 specimens, low-grade squamous intraepithelial lesions (LSIL) were diagnosed in 20 specimens, and atypical squamous cells of uncertain significance (ASCUS) were diagnosed in 11 specimens. Diagnoses of negativity for intraepithelial lesions or malignancy (NILM) were made in 24 specimens. Cell block sections were stained with hematoxylin and eosin and were immunostained with antibodies against p16INK4a protein and Ki-67 antigen. RESULTS The cytomorphologic diagnoses made using cell block preparations were as follows: SCC in 2 specimens, HSIL in 20 specimens, LSIL in 30 specimens, NILM in 32 specimens, and no diagnosis in 1 specimen. In 62 cases (73%), the diagnoses made using cell block preparations were in agreement with the ThinPrep diagnoses. Immunostaining of cell blocks for p16INK4a and Ki-67 exhibited a statistically significant association (P < 0.05) with the presence of significant lesions on either cell block or ThinPrep analysis. CONCLUSIONS To the authors' knowledge, p16INK4a has not been analyzed previously in ThinPrep cell blocks, and the correlation between Ki-67 expression and cell block diagnoses also has not been reported previously. The current results indicate that cell blocks prepared from residual ThinPrep material represent an additional reliable diagnostic tool in the evaluation of cervical samples. Furthermore, immunohistochemical studies may be helpful in differentiating significant preneoplastic changes from other cervical lesions, such as atrophy. Cancer (Cancer Cytopathol) 2004. © 2004 American Cancer Society.

Mesothelial cell hyperplasia, collagen balls, endometriosis, and endosalpingiosis are diagnostic pitfalls on peritoneal washing cytology in women who present with gynecologic lesions. Over an 8-month period, the peritoneal washings from 10 patients undergoing gynecologic surgery for presumed malignancy showed unusual cytologic findings, several of which posed diagnostic difficulties. The washings from four patients with ovarian carcinomas were cellular and contained clusters and strips of cells with cytologic atypia mimicking malignancy. Confirmation of their benign mesothelial origin was confirmed on immunohistochemistry utilizing cell block preparations. In two cases of endometrial endometrioid carcinoma, the washings contained several clusters of cells surrounding and/or admixed with a globular substance. Due to their similarity to endometrial cells, immunohistochemistry was performed on cell block preparations. The cells were positive for cytokeratin and negative for carcinoembryonic antigen and B72.3, confirming their mesothelial origin. In one case, clinically presumed to be a malignant mass, the washings contained tight clusters of cells with mild cytologic atypia admixed with hemosiderin-laden macrophages. In conjunction with the cell block findings, a diagnosis of endometriosis was made. Extensive endometriosis was found on the surgically resected specimen. In two cases, strips of ciliated epithelial cells resembling tubal epithelium were present on the cytologic and cell block preparations, consistent with endosalpingiosis. The peritoneal washings in one case contained several clusters and balls of atypical cells surrounding microcalcifications on cell block preparation. Since calcification within groups of cells in peritoneal washings always raised the possibility of malignancy, a serous carcinoma of the ovary, particularly of borderline malignancy, would have to be excluded. Fortunately, the resected specimen was free of tumor and showed calcified endosalpingiosis on the ovarian surface. Preparation of cell blocks from peritoneal washings is of value in the work-up and management of patients who present with cytologic mimickers of malignancy on fluid cytology. Diagn. Cytopathol. 2003;28:335–341. © 2003 Wiley-Liss, Inc.

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.

Introduction Conventional cell blocks (CCB) prepared from cytological specimens are very useful but the method is relatively time-consuming. Suitable modifications in cell-block techniques are beneficial for improving the turnaround time. We share our experience of a rapid microwave cell-block (MCB) technique. Aim and objectives To study the quality of routine and immunohistochemical (IHC) staining of cell-block sections from serous body fluids prepared by the MCB technique compared with the CCB technique. Method A total of 177 serous body fluid samples were processed by routine centrifugation technique, and the sediments were used for cell-block preparations by both conventional and rapid microwave methods. Cell-block sections were stained with haematoxylin and eosin stain. Haematoxylin and eosin staining quality was analysed using three parameters (cellularity, morphology and staining intensity). IHC for epithelial membrane antigen and calretinin were also performed, and the quality of staining was evaluated on 62/177 samples. Results were analysed using appropriate statistical tests. Results The time taken for processing cell blocks by the MCB method was 1 hour and 18 minutes compared to 13 hours and 45 minutes by CCB. The quality of sections by both methods showed good agreement for cellularity and intensity of staining, and moderate agreement for morphology. A 100% concordance was noted for distinguishing benign and malignant samples on morphology as well as with IHC stain results. Conclusion Although the techniques are comparable in terms of quality of routine and IHC staining, we recommend using the MCB technique due to its short turnaround time.

Background Acinic cell carcinoma (AcCC) is diagnostically challenging on fine-needle aspiration because it can mimic several other neoplasms or even normal acinar tissue. Immunopositivity for DOG1, especially circumferential membranous staining, can support the diagnosis of AcCC but is not entirely specific, and it is prone to technical and interpretive challenges on small specimens. NR4A3 (nuclear receptor subfamily 4 group A member 3) translocation and nuclear NR4A3 overexpression were recently described in the majority of AcCCs. Here, the authors evaluate the performance of NR4A3 immunohistochemistry (IHC) and NR4A3 break-apart fluorescence in situ hybridization (FISH) on cell block preparations and compare them with DOG1 IHC in distinguishing AcCC from other entities in the differential diagnosis. Methods The authors identified 34 cytology cell blocks with lesional cells, including 11 specimens of AcCC (2 of which derived from 1 patient and showed high-grade transformation) as well as 2 secretory carcinomas, 7 salivary duct carcinomas, 4 mucoepidermoid carcinomas, 3 oncocytomas, 3 renal cell carcinomas, and 6 specimens containing nonneoplastic salivary gland tissue. NR4A3 IHC, DOG1 IHC, and NR4A3 FISH were attempted for all cases. Results NR4A3 IHC had 81.8% sensitivity and 100% specificity for AcCC, whereas NR4A3 FISH had 36.4% sensitivity and 100% specificity, although 4 cases (3 mucoepidermoid carcinomas and 1 salivary gland tissue sample) could not be analyzed because of low cellularity. Notably, no normal acinar tissue specimens showed NR4A3 positivity by IHC or FISH. In addition, DOG1 IHC had 72.7% sensitivity and 92% specificity. Conclusions NR4A3 IHC is highly specific for the diagnosis of AcCC and is more sensitive than DOG1 IHC and NR4A3 FISH. In addition, NR4A3 IHC performance is not improved by the inclusion of DOG1 IHC. Finally, NR4A3 positivity resolves the perennial problem of distinguishing AcCC from normal acinar tissue.