Analysis of ThinPrep cytology in establishing the diagnosis of small cell carcinoma of lung

Pulmonary small cell carcinoma: Review, common and uncommon differentials, genomics and management

Lung cancer is the leading cause of cancer-related death worldwide. It is divided into sub-categories based upon morphology, immunostaining pattern, biology, molecular profile, and/or treatment options. Up until the early 2000s when driver mutations with targeted therapies were identified in a subset of adenocarcinomas, the most critical distinction of lung carcinomas was driven by differences in treatment between small cell carcinoma (SCC) and nonsmall cell lung carcinoma (NSCLC). The distinction between SCC and NSCLC remains critical in the 21st century for management, especially for advanced stage cancer. In the vast majority of cases, morphological features are sufficient to separate SCC from other types of lung cancers. In some instances, however, cytomorphological features and immunohistochemical overlap with other tumors, limited sample availability, and/or crush artifact pose diagnostic challenges. The aim of this review is to highlight salient features of SCC and ancillary studies to distinguish it from common and uncommon potential mimickers, as well as provide updates in genomics and management.

Morphologic Analysis of Cytomegalovirus Infected Cells in Bronchial Washing Cytology: Comparison of Liquid-Based Preparation and Conventional Smear

Background:

The cytopathic effects of cytomegalovirus (CMV) infection have been well described since the virus was first reported; however, the morphology of CMV infection has not been clearly studied. We examined the difference in detailed cytologic findings in bronchial washing cytology between liquid-based and conventionally prepared smears.

Methods:

Bronchial washing cytology was processed using either the conventional preparation (CP) or liquid-based preparation (LBP). Sixty-nine cells with typical cytopathic effects of CMV infection were detected on CP slides and 18 cells on LBP slides. Using the image analyzer, area, circumference, major axis, and minor axis of the cytoplasm, nucleus, and intranuclear inclusion were measured in singly scattered CMV-infected cells, and histiocytes were used as a control.

Results:

The mean cytoplasmic area of CMV-infected cells was 1.47 times larger than that of histiocytes in CP and 2.92 times larger in LBP (p<.05). The mean nuclear area of CMV-infected cells was 2.61 times larger than that of histiocytes in CP and 4.25 times larger in LBP (p<.05). The nucleus to cytoplasm ratio and intranuclear inclusion to cytoplasm ratio of the mean area, circumference, major axis, and minor axis in CP were larger than those in LBP (p<.05).

Conclusions:

The sizes of cytoplasm, nucleus, and intranuclear inclusion were larger in LBP than in CP, indicating that CMV-infected cells are easily detectable in LBP. However, the nucleus-to-cytoplasm ratio was larger in CP, suggesting that differentiation from malignancy or regenerative atypia requires caution in CP.

Introduction and utility of liquid-based cytology on aspiration biopsy of peripheral nodular lesions of the lung

In the present study, aspiration biopsy cytology (ABC) was used for the diagnosis of peripheral nodular lesions in the lung (PNLL), and liquid-based cytology (LBC) was carried out on the material collected to evaluate it in comparison with the conventional method (CM). The subjects comprised 130 cases that underwent computed tomography (CT)-guided ABC for PNLL. A total of 73 cases received a tumor resection, with a diagnosis based on the pathology, while 57 cases were followed up, as the tumor showed no change on the radiological examinations. Biopsy samples from these patients and lavage fluid from the aspiration needles were used for analysis. Cellular material was obtained by centrifugation of the lavage fluid, and samples were prepared by two methods, direct smearing and LBC according to the ThinPrep method. The samples were categorized into three diagnoses: i) Benign, ii) suspicion of malignancy and iii) malignant. Appropriate samples were collected in 72% of cases by LBC, but only in 36% of cases by the CM. There was no marked difference in cellular images between the two methods, with the exception of a few specific cases. LBC on its own provided sensitivity at 68%, specificity at 61% and accuracy at 65%, while a combination of LBC and biopsy markedly improved these figures to 94, 81 and 84%, respectively. The introduction of LBC is considered useful for the cytopathological diagnosis of PNLL by CT-guided ABC. LBC enables the examination of appropriate samples rich in cellular components and supports a biopsy-based diagnosis. A combination of these two methods provides even higher diagnostic accuracy, and LBC is considered an excellent method to evaluate these pathological samples.

The implementation of liquid-based cytology for lung and pleural-based diseases

OBJECTIVE

First introduced for the processing of cervico-vaginal samples, liquid-based cytology (LBC) soon found application in nongynecological specimens, including bronchoscopic brushings, washings and transcutaneous and transbronchial aspiration biopsy of the lung as well as pleural effusions. This article reviews the existing literature related to these specimens along with the authors' own experience.

STUDY DESIGN

A literature review was conducted through Ovid MEDLINE and PubMed search engines using several key words.

RESULTS

Most of the literature is based on data collected through the use of split samples. The data confirms that the use of LBC is an acceptable, and sometimes superior, alternative to the conventional preparations (CP). LBC offers several advantages, including the ability to transport in a stable collecting media, elimination of obscuring elements, ease of screening, excellent preservation, random representative sample, and application of ancillary techniques on additional preparations. Some diagnostic pitfalls related to the introduced artifacts were reported.

CONCLUSION

The utilization of LBC offers many advantages over CP and has a diagnostic accuracy that is equal to or surpasses that of CP. LBC affords a bridge to the future application of molecular and other ancillary techniques to cytology. Knowledge of the morphological artifacts is useful at the early stages of implementation.

Micronucleus evaluation of exfoliated buccal epithelial cells using liquid-based cytology preparation

OBJECTIVE

Micronuclei (MN) are biomarkers that can be applied to buccal epithelial cells to assess populations occupationally exposed to potentially carcinogenic agents. Liquid-based cytology (LBC) is a way to improve and refine the results obtained by this test.

STUDY DESIGN

Exfoliated buccal cells were collected from 40 subjects (20 construction workers from the Barretos Cancer Hospital and 20 administrative staff from the same institution). LBC and three stains (Feulgen/fast green, Papanicolaou and Giemsa) were used to prepare the slides. Student's t test was applied for statistical comparisons of the data. A p value of <0.05 was considered statistically significant.

RESULTS

Regardless of the stain employed, the frequency of MN was greater in the case group (Feulgen/fast green: 5.15; Papanicolaou: 29; Giemsa: 26) than in the control group (Feulgen/fast green: 2.30; Papanicolaou: 17; Giemsa: 15).

CONCLUSIONS

Using LBC to prepare slides and evaluate the frequency of MN potentially serves as a screening option for more comprehensive studies of cancer risk among populations occupationally exposed to potentially carcinogenic agents. In addition, the residual fluid enables the preparation of slides for DNA-specific stains that can be compared to those with Papanicolaou stain.

Application of ThinPrep bronchial brushing cytology in the early diagnosis of lung cancer: a retrospective study

The majority of lung cancer patients are diagnosed at advanced stages of disease. This study evaluated the diagnostic value of ThinPrep (TP) bronchial brushing cytology in lung cancer. A total of 595 patients with suspicious lung cancer were enrolled in this study. The bronchial brushing samples were prepared by TP. The data were then compared to histology of lung tissue samples. Histologically, 479 of these 595 patients were diagnosed with lung cancer, including 223 cases of lung squamous cell carcinoma (SCC), 77 cases of lung adenocarcinoma (ADC), and 152 cases of small cell lung carcinoma (SCLC). The TP cytology revealed a total of 460 cases of lung cancer (including 232 SCCs, 91 ADCs, and 108 SCLCs). The TP cytological technique had 87.06% sensitivity and 62.93% specificity in the diagnosis of lung cancer. Specifically, TP cytology confirmed 195 of 223 SCCs, 47 of 77 ADCs, and 94 of 152 SCLCs. The TP cytology showed 87.44% sensitivity and 90.05% specificity for the diagnosis of SCC, with a Matthew's correlation coefficient (MCC) of 0.820; while the sensitivity was reduced to 61.04% and the specificity was 90.93% for the diagnosis of ADC, with a MCC of 0.464. For the diagnosis of SCLC, the sensitivity was 61.84% and the specificity was 96.84%, with a MCC of 0.648. Thus, this study demonstrated the usefulness of TP bronchial brushing cytology in the early diagnosis of lung cancer, especially the early stage of lung SCC. A prospective clinical trial will verify these data before being translated into the clinic.

Comparison of diagnostic accuracy between CellprepPlus® and ThinPrep® liquid-based preparations in effusion cytology

Liquid-based cytology (LBC) is being increasingly used for body fluid specimens and has improved diagnostic accuracy when compared to conventional smears. We compared the diagnostic accuracy and cellular morphologic features between CellprepPlus® LBC and ThinPrep® LBC in effusion cytology. One hundred and eighty body fluid specimens, consisting of 119 pleural fluid specimens, 59 peritoneal fluid specimens, and 2 pericardial fluid specimens, were obtained from 166 patients. Equal volumes of body fluid from each specimen were used in the CellprepPlus® and ThinPrep® preparations. Sensitivity, specificity, and positive and negative predictive values were evaluated. In addition, we selected 16 specimens from patients with metastatic adenocarcinoma, confirmed them by both LBC preparations, and measured the size of the nucleus in the tumor cells in these specimens. The sensitivity of the CellprepPlus® and ThinPrep® methods was 73.1% and 50.0%, respectively. The specificity and positive predictive values were 100% for both LBC methods, and the negative predictive values of the CellprepPlus® and ThinPrep® methods were 90.9% and 83.3%, respectively. The average nuclear size of the tumor cells was calculated as 20.87 μm using the CellprepPlus® method and 15.08 μm using the ThinPrep® method (P < 0.05). The CellprepPlus® method provided better diagnostic accuracy of effusion cytology compared to the ThinPrep® method and revealed the characteristic morphological features of tumor cells, including large and hypochromatic nuclei, prominent nucleoli, distinct nuclear membranes, and high cellularity.

Immunohistochemical subtyping of nonsmall cell lung cancer not otherwise specified in fine-needle aspiration cytology: a retrospective study of 103 cases with surgical correlation

BACKGROUND

Histopathological subtyping of nonsmall cell lung cancer (NSCLC) is currently relevant in treatment decision because of a differential activity of specific therapeutic agents. Immunohistochemistry highlights cell differentiation lineages and, in this study, it was applied to maximize the proportion of accurately subtyped NSCLC not otherwise specified (NOS) on fine-needle aspiration cytology (FNAC) samples.

METHODS

Cell blocks from 103 FNAC samples with a morphological diagnosis of NSCLC-NOS were immunostained for cytokeratin (CK) 7, CK5, TTF1, and p63, whereas p40, napsin A (Naps-A), and desmocollin-3 (DSC-3) were only assessed in a subgroup of cases with discordant (CK7 and TTF1+ for nonsquamous, CK5 and p63+ for squamous) findings. Results were correlated with surgical specimens evaluated by morphology alone.

RESULTS

Thirty-seven (36%) tumors with CK7/TTF1+ and CK5/p63- corresponded to 35 cases of adenocarcinoma (ADC) and 2 cases of large cell carcinoma, whereas 9 (9%) cases with the reverse immunoprofile were squamous cell carcinoma (SQCC) at surgery (P < .001). Although the remaining 57 cases had different marker combinations, a correlation was found with ADC histology for TTF1+ samples (independent of other markers) and with SQCC for p63+/TTF1- immunophenotype (P < .001). p40 was never expressed in p63+ ADC, whereas Naps-A was restricted to ADC and DSC-3 to SQCC lineage. The percentage of unclassified NSCLC-NOS decreased from 36% to 14%. Combinations of 2 antibodies (TTF1/DSC-3 or p63/Naps-A) in the same section allowed diagnostic optimization in scant cytological samples.

CONCLUSIONS

[corrected] This 4-antibody panel approach may contribute to refine lung cancer classification in FNAC cell blocks, remarkably reducing the NSCLC-NOS diagnostic category.