Accurate assessment of cell density in low cellular liquid‐based cervical cytology

A. G. Siebers, J. A. W. M. van der Laak, R. Huberts‐Manders, J. E. M. Vedder and J. Bulten Accurate assessment of cell density in low cellular liquid‐based cervical cytology Objective: Scant cellularity is the most important source of unsatisfactory liquid‐based cytology. Although still being debated, low cellularity is thought to compromise the detection of squamous lesions. Thus, reliable assessment of cellularity is essential. The aim of the present study was to determine the cellularity range for ThinPrep^® slides of low cellularity and to establish the most accurate cell‐counting protocol. Methods: A series of 60 ThinPrep cases representing the full spectrum of adequate, ‘satisfactory but limited by’ (SBLB) and unsatisfactory reports were included. Two cell‐counting protocols with three different magnifications, using ×10, ×20 and ×40 objectives, were evaluated and related to the true cellularity, together with a reassessment of the degree of adequacy originally reported. The cell‐counting protocol that showed the highest correlation coefficient was considered the most accurate. Results: Based on seven (re)assessments a majority score for adequacy was established. There were 42 cases with a majority score ‘unsatisfactory’ or ‘SBLB’ (low cellularity) of which 41 contained fewer than 20 000 squamous cells; and 18 cases with a majority score ‘satisfactory’ of which one had fewer than 20 000 cells. The cell‐counting protocol that showed the significantly highest correlation with the reference standard was the Stichting Kwaliteitsbewaking Medische Laboratoriumdiagnostiek (SKML) protocol with a ×10 objective. Conclusions: ThinPrep slides reported as unsatisfactory or SBLB were shown to contain fewer than 20 000 squamous cells. The most accurate protocol for estimating the cellularity of these slides was cell counting in five non‐adjacent microscope fields along the horizontal axis and five along the vertical axis of the slide with a ×10 objective and applying a correction factor of 1.24× to correct for underestimation of the true cellularity.     

An audit of liquid‐based cervical cytology screening samples (ThinPrep and SurePath) reported as glandular neoplasia

S. A. Thiryayi, J. Marshall and D. N. Rana
An audit of liquid‐based cervical cytology screening samples (ThinPrep and SurePath) reported as glandular neoplasia Objectives: The aims of this study were to assess the number of cases diagnosed as glandular neoplasia (national report code 6) of cervical (6A) and non‐cervical (6B) types on ThinPrep (TP) and SurePath (SP) liquid‐based cytology (LBC) samples and to calculate the positive predictive value (PPV) of these diagnoses for significant glandular and/or squamous pathology for local audit and as a contribution to national data on glandular neoplasia. Methods: A computerized search identified all screening LBC samples reported as glandular neoplasia during the 24‐month period from January 2006 to December 2007. Corresponding histology samples were identified, with a minimum follow‐up period of 6 months for each case. Results: A total of 70 samples, representing 70 patients, were reported as glandular neoplasia, 39 TP (55.7%) and 31 SP (44.3%), with 46 samples (31 TP, 15 SP) reported as 6A and 24 samples (eight TP, 16 SP) as 6B. PPV of glandular neoplasia was calculated for a biopsy diagnosis of cervical glandular intraepithelial neoplasia/adenocarcinoma and/or cervical intraepithelial neoplasia (CIN) 2 or worse. The PPV of 6A was 100% for both TP and SP. The PPV of 6B for adenocarcinoma was 62.5% for TP and 66.7% for SP. The combined PPV for 6A + 6B was 92.3% for TP, 83.3% for SP and 88.4% combined. The overall pick‐up rates for the two methods were significantly different (TP 0.031%, SP 0.052%; P = 0.014). Histology showed only CIN3 with endocervical crypt involvement in nine TP cases and one SP case.     

Atypical squamous cells and low‐grade squamous intraepithelial lesion in cervical cytology: cytohistological correlation and implication for management in a low‐resource setting

N. Gupta, R. Srinivasan, R. Nijhawan, A. Rajwanshi, P. Dey, V. Suri and L. Dhaliwal Atypical squamous cells and low‐grade squamous intraepithelial lesion in cervical cytology: cytohistological correlation and implication for management in a low‐resource setting Objectives: To perform an audit of all cervical smears reported as atypical squamous cells (ASC) and low‐grade squamous intraepithelial lesion (LSIL) as in the Bethesda system (TBS) 2001, and determine their histological follow‐up and outcome when available, in order to define the threshold for colposcopic referral. Material and methods: A total of 25 203 cervical smears were screened over a period of 3 years (January 2006 – December 2008) and all ASC and LSIL smears were reviewed with the corresponding histological follow‐up. All cervical intraepithelial neoplasia (CIN) grade 2 lesions and above (CIN2+) were considered as clinically significant lesions for analysis. Results: Out of 25 203 cervical smears, 424 (1.7%) were reported as ASC and 113 (0.4%) as LSIL. Additionally, three were reported as atypical cells, not otherwise specified. The ASC : SIL ratio was 2.18 : 1. Follow‐up histology was available in 153 (36.8%) of the ASC cases and revealed CIN2+ lesions in 22 (14.4%). Follow‐up histology was available in 50 (44.2%) of LSIL cases and revealed clinically significant abnormalities in five (10%), all of which were CIN2. CIN3 and invasive squamous carcinomas were seen in 5.9% and 1.4%, respectively, of cases of ASC, and not seen in LSIL. Reclassification of ASC smears into ASC‐US (ASC‐undetermined significance) and ASC‐H (ASC‐ high grade SIL not excluded) revealed ASC‐H in 2.6% of all ASC smears, with a clinically significant outcome in 45.4%. Conclusion: In a low‐resource setting where human papillomavirus testing is unaffordable, the threshold for colposcopic referral and follow‐up histology should be ASC rather than SIL.     

Control specimens for immunocytochemistry in liquid‐based cytology

T. Hansen, H. Pedersen, V. Brauner and J. Hariri Control specimens for immunocytochemistry in liquid‐based cytology Objective Immunostaining necessitates the use of positive as well as negative controls, which is usually an easy procedure in immunohistochemistry (IHC). To find suitable control specimens for immunocytochemistry (ICC) is, on the other hand, a challenging task and to the best of our knowledge is not sufficiently dealt with in the English literature. The aim of this trial was to develop an applicable method to select, collect, process and store control specimens for ICC using liquid‐based cytology (LBC). Methods The study included 21 different antibodies, which were known to react with at least one of the cellular components from tonsils, serous fluids and bronchial washings. The LBC specimens from the tonsils were collected as SurePath? specimens (BD, Bencton, Dickinson and Company) by brushing the cut‐surface of a fresh tonsil and then immersing the brush head into the SurePath? vial. The serous fluids and bronchial washings were fixed in CytoRich Red? (BD). Some of the cellular suspensions from the tonsils and equal amounts of the serous fluid and the bronchial washings were also mixed as a cocktail. Unstained SurePath slides were then prepared on the PrepStain? (BD) Non‐GYN Program, and the unstained and dry slides were then stored at 5 °C to test the effect of storage on the preservation of the antigenicity. ICC was then performed on BenchMark‐XT?. Results Cellular components in unstained SurePath? slides reacted positively with relevant antibodies. Slides that were stored for up to 40 days did not loose staining intensity. Conclusion Specimens from body fluids and cell‐suspensions that are collected by brushing the cut‐surface from different types of fresh tissues or organs can be used as control specimens either separately or as mixtures. Dry and unstained slides can then be prepared and stored in a refrigerator for at least 40 days without loosing staining intensity.     

Increased diagnostic accuracy of atypical glandular cells in cervical liquid‐based cytology using cell blocks

E. K. J. Risse, J. P. Holierhoek, E. M. Meijer‐Marres, E. Ouwerkerk‐Noordam and M. E. Boon Increased diagnostic accuracy of atypical glandular cells in cervical liquid‐based cytology using cell blocks Objective: The purpose of this study was to reduce the number of diagnoses of atypical glandular cells (AGC). Residual material from the cervical ThinPrep® samples (Hologic, Marlboruogh, MA, USA) was used for cell blocks (CB) and immunohistochemistry (IHC). Methods: In 2007 there were 87 patients (0.12% of tests) with AGC on liquid‐based cytology (LBC) in the Leiden Cytology and Pathology Laboratory (LCPL) using the Bethesda System 2001 (TBS). CB with IHC was used for 26 of these cases. The vials still containing the brush (Cervex‐Brush^® Combi) were placed in a shaker for 10 minutes to dislodge the material trapped between the bristles. The residual sampling fluid was used to prepare paraffin sections (Shandon Cytoblock^®) stained with Papanicolaou and immunostaining. Results: Four of five cases with AGC not otherwise specified (NOS) were diagnosed with CB/IHC as benign mimics (endometrium, tubal metaplasia, follicular cervicitis, microglandular hyperplasia) and one of four with AGC‐favour neoplasia (FN) (endocervical polyp). In one of five cases with AGC‐NOS and in two of seven with AGC‐FN, CIN3 was found on subsequent histological biopsy. Of six cases diagnosed as adenocarcinoma in situ (AIS) on LBC with CB/IHC the diagnosis was confirmed in four; one was adenocarcinoma and one glandular atypia. Of eight cases diagnosed as adenocarcinoma on cytology and CB/IHC, the diagnosis was confirmed in three. The other five cases were found to be one each of AIS, squamous cell carcinoma, CIN3, CIN2 with glandular atypia, and cervical endometriosis. Conclusions: By reducing the number of benign mimics of AGC, we achieved a high proportion (16/26; 61.5%) of neoplastic or preneoplastic lesions (glandular or squamous) on histological outcome potentially avoiding colposcopy. Histological biopsy verification by the gynaecologist is needed for final diagnosis of AGC‐FN, AIS and adenocarcinoma.     

Interobserver concordance in the assessment of features used for the diagnosis of cervical atypical squamous cells and squamous intraepithelial lesions (ASC‐US,ASC‐H,LSIL and HSIL)

G. Bigras, J. Wilson, L. Russell, G. Johnson, D. Morel and M. Saddik
Interobserver concordance in the assessment of features used for the diagnosis of cervical atypical squamous cells and squamous intraepithelial lesions (ASC‐US, ASC‐H, LSIL and HSIL) Objectives: Given the well‐known poor reproducibility of cervical cytology diagnosis, especially for atypical squamous cells of undetermined significance (ASC‐US) and low‐grade squamous intraepithelial lesion (LSIL), this study surveyed reproducibility in the assessment of individual cytomorphological features. Methods: One hundred and fifty cells or groups of cells, with a variety of morphological appearances, including normal cells, high‐grade squamous intraepithelial lesion (HSIL), LSIL, ASC‐US and ASC cannot exclude HSIL (ASC‐H), were precisely marked on 150 different liquid‐based cytological preparations. They were analysed by 17 observers who assessed 17 cytological features including nuclear features (chromatin texture, nuclear outline, nuclear shape, etc.), cytoplasmic features (cell shape, cytoplasmic staining, cytoplasmic clearing, etc.) and group characteristics (nuclear polarity, cellular density, etc.). A total of 43 350 data scores were collected in a database using a web‐based survey. Kendall’s W and relative entropy indexes were utilized to compute concordance indexes of respectively ordinal and nominal variables. Results: Nuclear features have significantly lower reproducibility (0.46) compared with other cytological features (0.59). The feature with least agreement is assessment of chromatin texture. A small but significant difference in concordance was found between two subsets of observers with different levels of experience. Conclusion: Most previous studies assessing reproducibility of cytological diagnoses show, at best, moderate reproducibility among observers. This study focused on agreement regarding the presence of constituent morphological features used to recognize dyskaryosis and various grades of squamous intraepithelial lesions. A map of reproducibility indexes is presented that highlights, for daily practice or teaching, the robustness of features used for cytological assessment, recognizing that diagnosis is always based on a combination of features.     

Image analysis of peripheral compression artefacts of ThinPrep® liquid‐based cytology preparations

J. Choi, H. S. Shim, J.‐W. Song, S. W. Chae, Y.‐N. Lee, J. E. Kim and S. H. Kim
Image analysis of peripheral compression artefacts of ThinPrep^® liquid‐based cytology preparations Objective: ThinPrep (TP), one of the Food and Drug Administration‐approved liquid‐based cytology (LBC) preparations, is widely used for gynaecological and non‐gynaecological cytology samples. A unique physical artefact caused by the compression at the periphery in TP slides has not been adequately evaluated to date. Methods: We processed four established tumour cell lines (MKN28, MKN45, KG‐1 and NB4) and mononuclear cells isolated from whole blood over Ficoll‐Plaque for TP preparations. For this part of the study, we included five normal cervical LBC preparations. We then auto‐counted and auto‐measured the area, mean grey value and Feret’s diameter in both the inner disc and peripheral rim of the preparations by image morphometry. In addition, we compared the distribution of atypical cell groups in the peripheral rim and inner disc of 132 lung aspirates, 80 thyroid aspirates, 212 cerebrospinal fluids (CSFs) and 50 gynaecological samples. Results: The areas and Feret’s diameters of the cytoplasm in the peripheral compressed rim area were statistically larger than those of cells in the inner disc. The mean grey values of cells (cytoplasm and nucleus) in the peripheral compression rim were also smaller than those in the inner disc cells, leading to decreases in nuclear and cytoplasmic chromatism. Except for the mean grey values, the differences were not significant in the cervical samples. Conclusions: Cellular morphology may be markedly distorted in the peripheral rim, regardless of cell malignancy, which may lead to the misinterpretation of cells during the screening. Accordingly, cytological diagnosis based on the findings within the peripheral rim should take this phenomenon into account. Compressed cells found in the peripheral rim should be interpreted with caution when TP slides are used for cytopathological diagnosis.     

Factors contributing to false‐negative and potential false‐negative cytology reports in SurePath™ liquid‐based cervical cytology

N. Gupta, D. John, N. Dudding, J. Crossley and J. H. F. Smith
Factors contributing to false‐negative and potential false‐negative cytology reports in SurePath ? liquid‐based cervical cytology Objectives: The characteristics of false‐negative conventional cervical cytology smears have been well documented, but there is limited literature available for liquid‐based cytology (LBC), especially SurePath? samples. We aimed to assess the characteristics of false‐negative SurePath LBC samples. Methods: Over a period of 5 years, an audit of false‐negative reports in SurePath cervical cytology was undertaken. In a workload of 183, 112 samples, 481 (0.3%) false negatives were identified using two routes: those detected by routine laboratory internal quality control (rapid pre‐screening) (n = 463) and those reported as normal (true false negatives) with concurrent high‐grade cervical histology (n = 18). Ninety‐five false‐negative cases with a subsequent biopsy reported as at least cervical intraepithelial neoplasia grade 2 (CIN2+) were reviewed for a number of different cytomorphological features. Results: Of 95 samples with subsequent CIN2+, 30.5% predominately contained microbiopsies/hyperchromatic crowded cell groups (HCGs), 27.3% sparse dyskarytotic cells, 4.2% pale cell dyskaryosis, 6.3% small dyskaryotic cells; 3.2% were misinterpreted cells, 8.4% contained other distracting cells, 7.4% were low contrast, 5.3% were unexplained and 7.4% were true negatives. The mean number of microbiopsies/HCGs in that category was 4.6. The mean number of abnormal cells in the sparse dyskaryotic cell category was 13.8. Conclusions: Microbiopsies/HCGs were the commonest reason for false negatives. They were usually present in sufficient numbers to be detected but interpretation could be problematic. Dispersed single abnormal cells were usually not identified because of their scarcity or the presence of distracters.     

Initial axillary staging of breast cancer using ultrasound‐guided fine needle aspiration: a liquid‐based cytology study

A. Schiettecatte, C. Bourgain, C. Breucq, N. Buls, V. De Wilde and J. de Mey
Initial axillary staging of breast cancer using ultrasound‐guided fine needle aspiration: a liquid‐based cytology study Objective: To evaluate the preoperative detection of axillary metastasis combining ultrasound (US)‐guided fine needle aspiration cytology (FNAC) and liquid‐based cytology (Surepath^®) to reduce sentinel node procedures. Methods: In total, 148 patients with clinically negative lymph nodes and no preoperative therapy were included. All patients underwent preoperative ultrasound of the axilla with FNAC if suspicious lymph nodes were found. Complete axillary lymph node dissection was performed at primary surgery when FNAC was positive. All other patients underwent a sentinel node procedure. Results: US‐guided FNAC of the axilla revealed metastasis in 34 (23.0%) of the 148 patients. These 34 patients were 53.1% of all patients (n = 64) with proven axillary lymph node involvement. In 66 patients (44.6%), both ultrasound and histopathology were negative. Overall sensitivity of US‐guided FNAC was 50.0%, specificity 100%, positive predictive value 100% and negative predictive value 70.2%. In T1 tumours, all patients referred for sentinel node procedure were node‐negative. The correlation between malignant FNAC and histopathology was 100%. US‐guided liquid‐based FNAC in patients with no clinically positive lymph nodes reduced the necessity for a sentinel node procedure by 23.0%. Conclusions: We advocate that US‐guided fine needle aspiration (FNA) combined with liquid‐based cytology of axillary lymph nodes should be included in the preoperative staging of breast cancer.