Acta Cytologica最新文献

Background: Immunocytochemistry (ICC) is suitable for use on a range of cytology preparations, such as cell blocks, air-dried slides, ethanol-fixed slides, direct smears, cytospins, and liquid-based cytology (LBC) samples. However, it must be standardized against the gold standard of formalin-fixed paraffin-embedded tissues with adequate number of positive and negative controls. The role of ICC in lung cancer is crucial, as most lung cancer specimens are cytology samples. Accurate diagnosis and testing of certain biomarkers rely heavily on both diagnostic and predictive ICC.

Summary: Key ICC markers important in lung cancer include, but are not limited to, diagnostic ICCs such as TTF-1, p40, Napsin A, and p63, as well as predictive ICCs like ALK, ROS-1, PD-L1, and NTRK.

Key messages: With proper validation, immunocytochemistry for lung cancer can be effectively performed on direct smears, cytospins, and other specimens, even when resources for preparing cell blocks are unavailable. This is particularly true for diagnostic antibodies, but it is important to exercise caution with predictive ICC. Nonetheless, a low threshold for molecular testing should be maintained. PD-L1 ICC can be challenging and should ideally be performed on formalin-fixed cell blocks or biopsies when available.

Background: Cytological samples play a critical role in diagnosing advanced-stage tumors and those arising in difficult-to-reach anatomical sites such as the pancreatobiliary tract, lung, thyroid, suprarenal, pelvis, and others such as salivary glands. These samples are often the only available material for accurate diagnosis and for performing ancillary studies, such as immunocytochemistry (ICC) or the detection of molecular biomarkers.

Summary: While the use of immunohistochemistry is well established and standardized on formalin-fixed-paraffin-embedded histological tissue, in cytological samples, it presents unique challenges. Methods used for obtaining and processing these specimens are complex and are not standardized among laboratories. Moreover, there is also diversity in the types of cytological samples potentially suitable for ICC.

Key messages: This review explores the current landscape of ICC practices in European and North American laboratories, highlighting variability in methods and the need for standardization to ensure reliable results and reproducibility of ICC on cytological specimens.

Background: Fine-needle aspiration cytology serves as an important preoperative diagnostic tool for thyroid nodules. Despite its excellent diagnostic accuracy, diagnoses based solely on morphological observation can be challenging. Therefore, various ancillary diagnostic techniques have been applied, including immunocytochemistry (ICC). This review discusses the application and evaluation of ICC in thyroid fine needle aspiration.

Summary: Currently, three immunostaining preparation methods are available for cytological materials: liquid-based cytology, cell block, and cell transfer. ICC proves valuable in scenarios such as tumour diagnosis, assessment of differentiation and grading of carcinomas, estimation of primary organs in metastatic carcinomas, and detection of gene abnormalities. However, ICC, while useful, is not as accurate as immunohistochemistry and is more difficult to evaluate.

Key messages: If the pitfalls and limitations are understood and effectively navigated, ICC could play a significant role in decreasing the non-diagnostic rate, thus leading to more accurate and valuable diagnoses and reductions in the re-aspiration rate.

Introduction: Integrated on-slide positive controls are a standard quality assurance and quality control measure for immunohistochemistry on formalin-fixed paraffin-embedded tissue sections. They ensure identical analytical conditions for the control and patient samples. Our aim was to develop a procedure for preparing integrated on-slide positive controls for immunocytochemistry (ICC) on methanol-fixed cytospins.

Methods: Leftover diagnostic cytology samples with sufficient cells and confirmed expression of Calretinin, MOC31, TTF1, and hormone receptors were used as control samples. Cells from the control samples were deposited on the peripheral part of objective slides using standard cytocentrifuge equipment. Cytospins were immediately fixed in methanol for at least 30 min and then covered with polyethylene glycol (PEG). Completely dry and solid PEG was removed from the central part of the objective slides and stored at room temperature. Patient samples were subsequently added to the central part of a PEG-protected slide, with an appropriate positive control placed on the peripheral part, and then fixed in methanol. ICC was performed on the Ventana/Roche automated platform ULTRA, using optimized and validated protocols for TTF1, hormone receptors, and double immunostaining for Calretinin/MOC31. The quality of ICC reactions for both deposits on the same slide and potential cell carryover was evaluated retrospectively.

Results: In the period from October 2021 to December 2023, the majority of integrated positive controls (364/368, 99%) consistently exhibited unequivocally positive reactions for TTF-1 (n = 93), hormone receptors (n = 84), and double staining for Calretinin/MOC31 (n = 191), with easily interpretable ICC reactions on corresponding patient samples. No obvious carryover of cells from the control sample to the patient sample was observed during this period.

Conclusion: A novel approach developed for preparing integrated on-slide positive controls for ICC on methanol-fixed cytospins using standard cytocentrifugation is low-cost and can be widely applied in diagnostic cytology laboratories. Simultaneous ICC procedures for the control and patient samples on the same slide ensure identical analytical conditions for both samples, providing the highest level of quality control while reducing costs. Interpreting both ICC reactions on the same slide is time-efficient and convenient.

Background: Immunocytochemistry (ICC) is a widely available and extensively used ancillary method in diagnostic cytopathology with great variability in all test phases and a low level of adequate quality management. The non-standardized ICC landscape is now challenged with the introduction of the new European (EU) In Vitro Diagnostic Medical Devices Regulation (IVDR). According to this regulation, ICC on cytological slides falls under the category of Laboratory-Developed Tests (LDT), which requires rigorous standardization, validation, and thorough quality management.

Summary: Complete standardization of pre-analytical and analytical steps in ICC is impossible due to the complexity of the method and the constantly evolving antibodies, detection systems, and platforms. However, similar to the approach in immunohistochemistry, improving and standardizing "best practices" in quality management will result in high-quality, correct, accurate, and reliable ICC results. In this review, the current challenges of ICC in diagnostic cytopathology will be discussed, along with practical insights into ICC standardization and validation.

Key messages: Control slides prepared in the same manner as the patient samples, optimized ICC protocols, and participation in external quality control for ICC are the pillars of good quality management and essential to ensure safe and reliable patient diagnostics.

Introduction: Cancer genome analysis using next-generation sequencing requires adequate and high-quality DNA samples. Genomic analyses were conventionally performed using formalin-fixed paraffin-embedded sections rather than cytology samples such as cell block or smear specimens. Specimens collected from liquid-based cytology (LBC) have the potential to be sources of high-quality DNA suitable for genetic analysis even after long-term storage.

Methods: We collected breast tumor/lesion fractions from 92 residual LBC specimens using fine-needle aspiration (FNA) biopsy, including breast carcinoma (1 invasive carcinoma and 4 ductal carcinomas in situ), papillomatous lesion (5 intraductal papillomas), and fibroepithelial lesion (19 phyllodes tumors and 53 fibroadenomas) samples, and others (1 ductal adenoma, 1 hamartoma, 1 fibrocystic disease, and 7 unknown). DNA was extracted from all samples and subjected to DNA integrity number (DIN) score analysis.

Results: Average DIN score collected from 92 LBC specimens was significantly higher score. In addition, high-quality DNA with high DIN values (7.39 ± 0.80) was successfully extracted more than 12 months after storage of residual LBC specimens.

Conclusion: Residual LBC specimens collected from FNA of the breast were verified to carry high-quality DNA and could serve as an alternate source for genetic analysis.

Introduction: Pulmonary Langerhans cell histiocytosis (PLCH) is a rare interstitial lung disease characterized by the accumulation of Langerhans cells within the lung tissue. The diagnosis of PLCH traditionally involves clinical, radiological, and lung biopsy histopathological evaluations.

Case presentation: We present 2 cases where the diagnosis of PLCH was confirmed through the analysis of bronchoalveolar lavage (BAL) fluid cytology using immunoperoxidase technique, highlighting the significance of this minimally invasive technique in the diagnostic process. Clinical and radiological examination suggested advanced interstitial lung disease characterized by a fibrocystic pattern in both cases. The cytologic analysis of the BAL fluid revealed typical histiocytes with longitudinal grooves and eosinophils, which was better seen on liquid-based cytology (LBC) smears. ICC with CD1a, Langerin, and S-100 confirmed the diagnosis of PLCH.

Conclusion: Detecting PLCH through the examination of BAL cytology poses challenges, yet it is achievable, particularly with the assistance of LBC and ICC.