Early diagnosis of mesothelioma in serous effusions using AgNOR analysis

OBJECTIVE: To compare the results of conventional cytology, DNA image cytometry, immunocytochemistry and argyrophilic nucleolar organizer region (AgNOR) analysis for the diagnosis of malignant cells in serous effusions. STUDY DESIGN: One hundred twenty effusions, 40 with carcinoses, 40 with malignant mesotheliomas and 40 without tumor cells on follow-up were studied by conventional cytology and three adjunctive methods. RESULTS: Unequivocal tumor cells were detected in 92.5% of effusions due to carcinoses and in 45% due to mesotheliomas. Applying immunocytochemistry with BerEP-4 positivity and DNA image cytometry with aneuploidy as a marker revealed 100% of carcinoses and 71.7% of mesotheliomas. Applying the experimentally found thresholds of 2.5 AgNORs as "satellites" and 4.5 AgNORs as "satellites and clusters" together as mean values per nucleus resulted in a 95% correct rate of mesothelioma and 100% rate of carcinoma cell identification without false positive diagnoses. CONCLUSION: AgNOR analysis may be a useful adjunct to other methods in the routine diagnosis of malignant serous effusions. It seems to be the most sensitive method in early cytologic diagnosis of mesotheliomas in effusions. Seventy-three percent of malignant mesotheliomas were diagnosed cytologically at first on effusions. Forty-seven percent of patients with malignant mesotheliomas were identified at the early tumor stage T1 N0 M0.     

DNA flow cytometry of pleural effusions. Comparison with pathology for the diagnosis of malignancy

A study was undertaken to determine the potential value of DNA flow cytometry (FCM) for the diagnosis of malignancy in pleural effusions and to compare its results with those of traditional cytomorphology. Forty-one pleural fluids from 37 patients were evaluated by DNA FCM and routine cytologic techniques. Of the 41 pleural fluids, 29 (70.7%) demonstrated an abnormal DNA content by FCM. Two of the 29 pleural fluids had been originally diagnosed as benign by cytology. Cytologic review of these two cases showed no abnormal cells; therefore, there were no false-negative cases based on cytology. In 12 (29.3%) of the 41 fluids, DNA FCM and cytologic evaluation both indicated benign processes. Our preliminary observations indicate that FCM is an accurate and reliable technique that may be of aid in the diagnosis of malignant effusions. The technique may prove to be of special value in the differential diagnosis of reactive mesothelial cells versus malignant mesothelioma as well as for following patients who receive chemotherapy for malignant pleural effusions. DNA FCM may also complement cytomorphologic diagnoses in other serous, exfoliative or aspiration material.     

Immunocytochemical Staining of Serous Effusions With the Monoclonal Antibody Ber-Ep4

Cytospin preparations were made from 102 serous effusions for immunocytochemical staining using a panel of monoclonal antibodies including a new monoclonal antibody Ber-EP4. On cytological examination, 32 fluids were reported to contain tumour cells consistent with metastatic adenocarcinoma; 66 contained benign cells only and three were reported to contain cells suspicious of malignancy. One effusion contained tumour cells consistent with malignant mesothelioma. Positive staining of the tumour cells with Ber-EP4 was observed in the 32 effusions (100%) which contained adenocarcinoma cells. No staining of the mesothelial cells in these 32 specimens was observed. Carcinoembryonic antigen, epithelial membrane antigen Ca2 and CD15 staining of tumour cells was noted in 53%, 50%, 50% and 9% of these cases, respectively. None of the mesothelial cells in the benign effusions stained with Ber-EP4. Nor did the malignant mesothelial cells in the only case of malignant mesothelioma. These findings suggest that Ber-EP4 is a valuable addition to antibodies available for the differential diagnosis of mesothelial cells and adenocarcinoma cells in serous effusions.     

Limitations of detection of malignancy in pleural effusions using ELISA-based TRAP assay: comparison with cytological examination

OBJECTIVE: Telomerase is active in almost all cancers from various organs but is not detectable in most normal cells. Thus, telomerase activity might be a universal and specific marker for diagnosing malignancy. The aim was to evaluate the potential use of the ELISA-based TRAP assay to detect malignancy in pleural effusion, and to compare it with conventional cytological examination. METHODS: Using the ELISA-based TRAP assay, telomerase activity was examined in 94 consecutive pleural effusions submitted for cytological examination. RESULTS: According to the results of cytology, the 94 samples were divided into two groups: group I, 79 non-malignant pleural effusions, including group IA, no association with a malignant tumour, a control group (n = 63), and group IB, associated with a malignant tumour (n = 16); and group II, 15 malignant pleural effusions. Telomerase activity was detected in five of 63 samples in group IA (7.9%), four of 16 samples in group IB (25%), and six of 15 samples in group II (40%). All five false-positive effusions were from patients with tuberculosis. Comparing group II with group IA, the TRAP assay showed 40% sensitivity, 92.1% specificity, 54.5% positive and 86.6% negative predictive value, and 82.1% accuracy. However, the detection rate of the TRAP assay (88.9%) was higher than that of the cytological examination (66.7%) in lung cancer-inflicted pleural effusions. CONCLUSION: The ELISA-based TRAP assay is relatively insensitive; therefore, it is unsuitable as a routine diagnostic tool for pleural effusion. False-positive telomerase activity due to lymphocytic contamination may weaken its diagnostic value for malignant effusions in a tuberculosis-endemic area.     

Could nuclear matrix protein 22 (NMP22) play a role with urine cytology in screening for bladder cancer? – experience at Kuwait University

Objectives:  This prospective study was undertaken to evaluate nuclear matrix protein (NMP22) compared to urine cytology in the detection of bladder cancer and also to determine whether indexing suspicious cytology to NMP22 could enhance the clinical utility of cytology.
Methods:  Cytological findings of voided urine collected prior to a cystoscopic biopsy were correlated with urine NMP22 assay in 46 patients attending the urology clinic in Mubarak Al-Kabeer Hospital. The patients were clinically categorized into newly diagnosed cases of transitional cell carcinoma (TCC), recurrent TCC, TCC in remission and controls.
Results:  Using histological diagnosis as the gold standard the sensitivity and specificity of NMP22 were 78% and 43% respectively and of cases with malignant urine cytology were 30% and 87% respectively. If suspicious and malignant cytology were combined as positive results the sensitivity increased significantly to 87% while the specificity decreased but not significantly to 74%. Suspicious or malignant cytology enhanced by positive NMP22 gave a sensitivity of 70% and specificity of 87% neither of which was significantly different from cytology alone. There were three false positive cases on cytology and 13 false positive cases on NMP22 assay. There were three false negative cytology and five false negative NMP22 cases but only one was false negative for both, resulting in a high sensitivity (96%) but low specificity (30%) if either positive NMP22 or malignant or suspicious cytology was taken as a positive result.
Conclusion:  Combining NMP22 with malignant or suspicious cytological result improved sensitivity for the detection of bladder cancer but with a major decrease in specificity, suggesting a potential role in screening rather than diagnosis.     

Immunocytochemical study of malignant lymphoma in serous effusions

OBJECTIVE: To cytologically evaluate a large series of serous effusions associated with malignant lymphoma (ML), identify the immunoreaction patterns of the cells from selected positive cases and to investigate the correlation of cytomorphology with tissue section diagnosis. STUDY DESIGN: From 1966 to 1990, a review of the files of the Department of Anatomic Pathology, A. C. Camargo Hospital, disclosed 4,297 cases of serous effusions, 256 of which were associated with ML. Cytopathologically positive cases were selected for immunocytochemical study. All paraffin sections stained with hematoxylin and eosin were reviewed to confirm the malignancy of the cases. Immunostaining was performed on both cytocentrifuge slides previously stained with Papanicolaou stain and new sections of the biopsy samples using the immunoperoxidase method and avidin-biotin complex with monoclonal mouse antihuman B-cell marker L-26 and monoclonal (mouse) antihuman T-cell marker UCHL-1. RESULTS: Immunocytochemical reactions were performed in 54 cases: 22 were pan-B positive and 10 pan-T positive; 24 cases showed no reactivity for either monoclonal antibody. Immunohistochemical reactions were performed in 24 available cases: 15 were pan-B positive and pan-T positive; 3 cases showed no reactivity for either monoclonal antibody. Cytohistoimmunoreactions were similar in 11 pan-B positive cases and 2 pan-T positive cases. Three cases were negative for both markers, 4 cases were pan-T positive in tissue samples and negative in cytocentrifuge smears, 3 cases were pan-B positive in tissue and negative on cytology and 3 cases were negative for both markers in both tissue and cytologic specimens. CONCLUSION: Cytology is an effective method of evaluating serous effusions associated with malignant lymphoma: no false positive diagnosis was observed in this series. Immunophenotyping of lymphoid cells is useful to classify and confirm the cytologic diagnosis.     

Comparison of Monoclonal Antibodies Aua1 and Ber Ep4 With Anti-Cea For Detecting Carcinoma Cells In Serous Effusions and Distinguishing Them From Mesothelial Cells

Commercially available monoclonal antibodies AUA1, BER EP4 and carcinoembryonic antigen (CEA) were applied to cell blocks from 95 serous effusions. AUA1 and BER EP4 were reactive with 89% of effusions known to contain carcinoma cells, and anti-CEA with 71%. They also reacted with cells in two effusions from patients with malignant disease which were regarded as negative on conventional cytological examination of Papanicolaou-stained smears. They were negative in all but one of the benign effusions. Using all three antibodies, 95% of effusions containing carcinoma cells were detected. Use of these antibodies could improve the cytological diagnosis of serous effusions.     

Use of liquid-based cytology in serous fluids: a comparison with conventional cytopreparatory techniques

OBJECTIVE: To examine the performance of liquid-based cytology (LBC) on body cavity fluids as compared with conventional cytopreparatory techniques. STUDY DESIGN: Slides from a total of 592 serous fluids, effusions as well as intraoperative washings, were reviewed. Of these fluids, 301 were collected before and 291 after the introduction of the PrepStain LBC (TriPath Imaging, Burlington, North Carolina, U.S.A.) in our laboratory. RESULTS: PrepStain thin layers showed excellent morphology on a clear background, with preservation of 3-dimensional configurations and a sufficient amount of extracellular material to allow an accurate diagnosis. Cytopreparation, screening and interpretation of LBC were less time consuming. Moreover, when the performance of the various cytopreparatory techniques in malignant fluids was studied, PrepStain thin layers excelled over conventional cytopreparatory methods in showing a significantly lower false negative rate (P=.0414). CONCLUSION: Our findings indicate that in body fluid cytology, thin layers can safely replace other types of wet-fixed preparations, resulting in enhanced specimen quality and diminished false negative rates.     

Correlation between the papanicolaou stain and the Wright-Giemsa stain in body fluids: a quality assurance study

OBJECTIVE: To compare the use of Papanicolaou and Wright-Giemsa stains for the evaluation of body fluids in cytology and hematology laboratories and determine whether other factors account for discrepancies in diagnosis. STUDY DESIGN: We retrospectively reviewed cytopathology reports of peritoneal, pleural, and cerebrospinal fluids received by hematology and cytology laboratories for 1 year. Cases were divided into 3 categories-benign, atypical, and malignant--and slides of discrepant diagnoses were reviewed. RESULTS: During this period, 198 of 3212 (0.61%) cases received by the hematology laboratory and 252 of 4402 (0.57%) cases received by the cytology laboratory were diagnosed as malignant or atypical. Of 3212 cases simultaneously received by the cytology and hematology laboratories, 17 diagnosed as malignant by hematology were diagnosed benign by cytology (sensitivity 96%). Sixteen cases diagnosed as malignant by cytology were diagnosed as benign by hematology (sensitivity 97%). No benign cases were diagnosed as malignant (specificity 100%). Review of the glass slides of the discrepant cases revealed 8 cases undercalled by hematology and 7 cases undercalled by cytology. CONCLUSION: Papanicolaou stain is superior for carcinoma and Wright-Giemsa stain for hematopoietic disorders, but used together they may reduce false negative results. Delays in processing, staining technique, and interobserver variability contribute to discrepancy.     

Diagnosis of bladder cancer with urinary cytology, immunocytology and DNA-image-cytometry.

DNA-image-cytometry and antibodies directed against the Lewis X- and the 486p 3/12 antigen were applied to improve diagnostic accuracy of urinary cytology for the detection of bladder cancer. Cytology, immunocytology and DNA-image-cytometry were performed in spontaneously voided urine samples and barbotage bladder washings from 71 patients. The DNA content was determined using the CM-1 Cytometer according to the recommendation of the ESCAP Consensus Report on Standardization of DNA-image-cytometry (1995). For immunocytological examination we used the monoclonal anti Lewis X antibody P-12 and antibody 486p 3/12. All patients underwent subsequent cystoscopy and for any suspicious lesion biopsy or transurethral resection was done. Histological findings revealed 31 patients with transitional cell carcinomas of different stages and grades of malignancy. 40 patients had various benign diseases of the urinary bladder. Cytology yielded a sensitivity of 68% and a specificity of 100%. DNA aneuploidy was detected in 81% of cancer patients with a specificity of 100%. By combination of these two methods the overall sensitivity increased to 87%. Immunocytology with Lewis X and 486p 3/12 antibodies showed reactivity in 84% and 87% in combination with a specificity of 80% and 70%, respectively. By combining urinary cytology, immunocytology and/or DNA-image-cytometry the overall sensitivity increased to 94% with no change in specificity. DNA-image-cytometry should be used to evaluate particularly urothelial cells suspicious for malignancy in urinary specimens. Because of low specificity the monoclonal antibodies against Lewis X- and 486p 3/12 antigens are not helpful in screening for bladder cancer. Nevertheless, their high sensitivity may justify their use in case DNA image cytometry is not available and in the follow up of patients with transitional cell carcinoma.     

The diagnostic and molecular characteristics of malignant mesothelioma and ovarian/peritoneal serous carcinoma

B. Davidson The diagnostic and molecular characteristics of malignant mesothelioma and ovarian/peritoneal serous carcinoma Malignant mesothelioma and ovarian/peritoneal serous carcinoma are two of the most common tumours affecting the serosal cavities. Unlike other malignant tumours diagnosed at this anatomical site, such as lung and breast carcinoma, malignant mesothelioma and serous carcinoma share a common histogenesis, may be difficult to differentiate morphologically, and co‐express many of the diagnostic markers used by cytopathologists in effusion diagnosis. Selected markers have nevertheless shown sufficient sensitivity and specificity to differentiate serous carcinoma from malignant mesothelioma effectively. Recently, our group applied high throughput technology to the identification of new markers that may aid in differentiating these two cancer types and validated several of these markers in follow‐up studies. This review will present current data regarding the diagnostic and biological aspects of malignant mesothelioma and ovarian/peritoneal serous carcinoma.     

Aspiration cytology of 147 adnexal cysts with histologic correlation.

OBJECTIVE: To assess the usefulness of cytology in the diagnosis of 147 histologically established adnexal cysts. STUDY DESIGN: Retrospective, macro-microscopic study based on fluid aspirated from 132 ovarian and 15 extraovarian cysts and projected as a cytohistologic correlation. RESULTS: Typical macroscopic features were identified in 76% of endometriotic cysts, in 53% of mucinous neoplasms and in 67% of dermoid cysts. Cytology helped to identify 67% of nonneoplastic and 56% of neoplastic cysts. The lowest diagnostic sensitivities were observed in functional cysts and benign serous neoplasms (50%), while the highest were shown by endometriotic cysts (76%) and malignant epithelial neoplasms (71%). Inadequate samples were obtained from all types of cysts, even malignant ones (two mucinous cystadenocarcinomas). Diagnostic cytology was useless in extraovarian cysts (33% sensitivity). An adult granulosa cell tumor was erroneously diagnosed as a follicular cyst by cytologic examination. CONCLUSION: Examination of the cyst fluids obtained by aspiration demonstrated low sensitivity, with 43% of inadequate samples obtained from all types of cysts. Malignant cystic neoplasms may be overlooked in inadequate samples. Our study also revealed that specificity in this type of analysis is high in inadequate samples, provided that the technique is carried out correctly.     

Fine needle aspiration cytology in ovarian lesions: an institutional experience of 584 cases

N. Gupta, A. Rajwanshi, L. K. Dhaliwal, N. Khandelwal, P. Dey, R. Srinivasan and R. Nijhawan
Fine needle aspiration cytology in ovarian lesions: an institutional experience of 584 cases Objective: To assess the diagnostic value of fine needle aspiration cytology (FNAC) in ovarian lesions. Methods: This was a retrospective study of ultrasound‐guided (US) FNAC of 584 ovarian lesions from January 1998 to July 2010. The lesions were categorized into non‐neoplastic lesions, neoplastic lesions and inadequate aspirates. The results were compared with the corresponding histopathology whenever available. Results: Of the 584 lesions, 180 (30.8%) were reported as non‐neoplastic (48 non‐specific inflammation, 11 tuberculosis, 63 functional cysts and 58 endometriotic cysts), 249 (42.6%) as neoplastic (81 benign lesions/tumours and 168 malignant) and 155 (26.5%) as inadequate. Based on the subsequent histopathology, which was available in 121 (20.7%), the cases were divided into those that were concordant and discordant. Concordant cases comprised 92/121 (76%), including 28 non‐neoplastic lesions (seven non‐specific inflammation, nine functional cysts and 12 endometriotic cysts), 42 surface epithelial tumours (13 benign and 29 malignant), 10 germ cell tumours (five mature cystic teratomas and five mixed germ cell tumours), seven sex‐cord stromal tumours (three granulosa cell tumours, one sclerosing stromal tumour, one strümal leutoma, one Sertoli Leydig cell tumour and one malignant Sertoli cell tumour) and five miscellaneous lesions (one plasma cell tumour, two leiomyosarcomas and two cases of necrosis). Discordant cases comprised 29/121 (24%) (21were inconclusive or inadequate on cytology), including four endometriotic cysts, 14 surface epithelial tumours (one cystadenofibroma, one borderline mucinous tumour and 12 carcinomas), five germ cell tumours (two immature teratomas and three mature cystic teratomas), two thecomas, one fibroma, one sclerosing stromal tumour, one fibrosarcoma and one myxoma. FNAC sensitivity for a diagnosis of malignancy was 85.7%, specificity 98.0%, positive predictive value 97.7%, negative predictive value 87.7% and accuracy 92.0%, if 21 inconclusive/inadequate FNACs were excluded; with the latter taken as false negatives, sensitivity was 73.7% and accuracy 76.0%. Conclusion: FNAC has a high specificity for diagnosis of ovarian/adnexal lesions but greater experience is required for the accurate subtyping of neoplasms and sensitivity is limited by inconclusive/inadequate results.     

Utility of imprint cytology for early presumptive diagnosis in clinically suspicious cervical cancer

OBJECTIVE: To determine the utility of imprint cytology (IC) in providing an early presumptive diagnosis of clinically suspected cervical carcinoma. STUDY DESIGN: A total of 219 clinically suspicious cervical cancer cases underwent Pap test, punch biopsy and IC at the same sitting. Correlations were performed between these diagnostic modalities to determine the sensitivity and specificity of IC in diagnosis of cervical cancer. RESULTS: The overall accuracy of IC in detecting cervical cancers was 96.2%. About 78% of squamous cell carcinomas (SCC), 60% of adenocarcinomas and 100% of small cell carcinoma could be accurately typed on imprints. Twelve malignant lesions were diagnosed on IC among 26 unsatisfactory biopsies. Although there was no false positive result, 3.5% false negative diagnoses were given on IC. The sensitivity and specificity of imprint smear cytology to detect malignancy was 96.2% and 100%. Agreement between imprint cytology and Pap smear diagnosis of malignancy was 95.3%. kappa Statistics revealed excellent agreement between imprints and biopsies and between imprints and Pap smears in diagnosis of malignant lesions. CONCLUSION: IC can be used as an adjunctive technique for an early and reliable preliminary presumptive diagnosis of cancer of the uterine cervix.     

Value of EUS‐FNA cytological preparations compared with cell block sections in the diagnosis of pancreatic solid tumours

Y. Kopelman, S. Marmor, I. Ashkenazi and Z. Fireman
Value of EUS‐FNA cytological preparations compared with cell block sections in the diagnosis of pancreatic solid tumours Objective: Endoscopic ultrasound‐guided fine needle aspiration (EUS‐FNA) is performed in order to achieve a definite tissue diagnosis of pancreatic lesions. This in turn is a guide to the appropriate treatment for the patient. Tissue samples collected by the same needle for cytological preparations and cell block histological sections (often referred to as FNA‐cytology and FNA–biopsy, respectively) are handled differently. The specific contribution of each of these tests was evaluated. Methods: One hundred and two consecutive patients underwent EUS‐FNA while being investigated for pancreatic solid lesions. Diagnosis was made by cytology, cell block sections or both. The diagnosis was confirmed by clinical outcome. Results: Male/female ratio was 61/41. Mean age was 65 ± 12 years (range, 22–94). Mean lesion size was 3.1 ± 1.8 cm (range, 0.6–10 cm); 68% were >2 cm and 75% were located in the pancreatic head. The average number of needle passes was two (range, 1–4 passes). Final tissue diagnosis was malignant in 66 (65%) patients. Sensitivity, specificity and accuracy were 73%, 94% and 81%, respectively, for cytology alone, and 63%, 100% and 78%, for cell blocks alone. Eighty‐two patients (80%) had cytology and cell blocks, which matched in 64 (78%) patients. EUS‐FNA results that relied on both techniques had 84% sensitivity, 94% specificity and 88% accuracy. Cytology revealed 13 malignancies not diagnosed on cell blocks, while cell blocks revealed five malignancies not diagnosed by cytology. Malignant lesions were more common in men; they were larger in size and located in the pancreatic head. Conclusion: EUS‐FNA cytology was more sensitive than cell blocks but less specific for the diagnosis of solid pancreatic lesions. The two methods are complementary and implementing both improves the diagnostic value of EUS‐FNA.     

O-9AUDIT ON BK VIRUS DETECTION IN RENAL TRANSPLANT RECIPIENTS

Introduction and Aims:  The sensitivity of bronchial cytology (brushings, washings) is in the region of 70–80%. Therefore a significant number of false negatives occur. The main aims of this study were to: (i) To identify negative bronchial washings and brushings performed in 2004 with malignant follow-up and (ii) To ascertain the cause of the false negative result where possible. 56 patients with negative bronchial cytology and subsequent malignant follow-up on a pulmonary specimen were identified. These cases formed the basis of the study.
Results:  In our series peripheral tumour location and specimen inadequacy accounted for the majority of false negative results. Malignant cells were missed in a minority of cases (5 of 56). An explanation for failure of diagnosis in 4 of the 5 cases was paucity of malignant cells. In one case of small cell carcinoma, malignant cells were abundant, but were not recognized.
Recommendations:  What can be done to reduce the false negative rate?
(1) In cases where radiology has indicated that the tumour is peripherally located patients could proceed directly to fine needle aspiration.
(2) Improved communication between clinicians and pathologists is required in relation to: (a) specimen adequacy and (b) degree of clinical suspicion.     

Outcomes of endoscopic ultrasound‐guided pancreatic FNAC diagnosis for solid and cystic lesions at Manchester Royal Infirmary based upon the Papanicolaou Society of Cytopathology pancreaticobiliary terminology classification scheme

Objective

To compare endoscopic ultrasound (EUS)‐FNAC diagnosis of pancreatic lesions with patient outcome based upon the Papanicolaou Society of Cytopathology pancreaticobiliary terminology classification scheme diagnostic categories: Panc 1 (non‐diagnostic); Panc 2 (negative for malignancy/neoplasia); Panc 3 (atypical); Panc 4B (neoplastic, benign); Panc 4O (neoplastic, other); Panc 5 (suspicious of malignancy); and Panc 6 (positive/malignant).

Methods

All EUS‐FNA pancreas specimens taken at Manchester Royal Infirmary in 2015 were prospectively classified according to the above scheme at the time of cytology reporting and data recorded prospectively. Subsequently, outcomes based on clinical follow‐up or histopathology diagnosis were compared with the cytology diagnosis.

Results

120 EUS‐FNA pancreas specimens from 111 patients were received, of which 112 (93.3%) specimens had follow‐up data. There were 79 and 41 EUS‐FNA pancreas specimens from solid and cystic lesions, respectively. Based on the cytology diagnosis the specimens were classified as Panc 1 (7.5%), Panc 2 (33.3%), Panc 3 (2.5%), Panc 4B (2.5%), Panc 4O (15.0%), Panc 5 (3.3%) and Panc 6 (35.9%). The performance indicators for diagnosis of malignancy or neoplasia with malignant potential, included sensitivity (95.4%), specificity (100%), positive predictive value (100%), negative predictive value (92.3%), false positive rate (0%) and false negative rate (4.6%).

Conclusions

The Papanicolaou Society of Cytopathology pancreaticobiliary terminology classification scheme is a logical system that can easily be introduced in a diagnostic cytopathology service. This classification scheme acts as an aid to diagnostic reporting, clear communication of significant results including risk of neoplasia/malignancy to clinicians, clinical audit and comparison of results with other centres.     

Immunocytochemical detection of Ki‐67 in Diff‐Quik‐stained cytological smears of canine mammary gland tumours

U.S. Choi and D.Y. Kim Immunocytochemical detection of Ki‐67 in Diff‐Quik‐stained cytological smears of canine mammary gland tumours Objective: To investigate whether Diff‐Quik stained fine needle aspirate smears can be used to evaluate Ki‐67 expression by immunocytochemistry. Methods: Both cytological and histological samples were obtained from 24 dogs with spontaneously developed mammary gland tumours. The cytological and histological specimens were examined by Diff‐Quik and H&E stains, respectively. After examination, both samples were immunostained using the same Ki‐67 antibody. The % Ki‐67 values were calculated based on the percentage of positively stained tumour cells per 500 and 1000 tumour cells in cytology and histology specimens, respectively. Results: Ki‐67 staining was successful in 17/24 smears (71%) and 19/23 sections (83%). The correlation coefficient between the percentage of Ki‐67‐positive cells in cytological smears and in the histological sections was 0.677 (P < 0.01). These values were significantly different between histologically benign and malignant tumour groups both in cytology and histology samples (P < 0.001). The threshold value of the percentage of Ki‐67‐positive cells for distinguishing benign from malignant tumours was set at 4.85% with 90.9% sensitivity and 92.3% specificity by Receiver Operating Characteristic (ROC) curve using histopathology as the gold standard. Conclusion: Diff‐Quik‐stained cytology smears can be used to detect the presence of Ki‐67 antigen when histology sections are not available.