Comparison of plasma-thrombin, HistoGel, and CellGel cell block preparation methods with paired ThinPrep slides in the setting of mediastinal granulomatous disease

Patterns of HER2 expression and genomic correlates in lung cancer, with a focus on preanalytical variables impacting immunohistochemical staining results

AIMS

Fam-trastuzumab deruxtecan-nxki (T-DXd) was recently approved for advanced stage or metastatic solid tumours with human epidermal growth factor receptor 2 (HER2) immunohistochemical (IHC) 3+ staining. Data on HER2 IHC testing and knowledge of genomic correlates in lung cancer are scarce. This study analyses genomic characteristics of HER2-expressing tumours and addresses issues with preanalytical variables for lung cancer specimens.

METHODS

HER2 IHC staining was performed on selected archival cytology and surgical pathology lung cancer specimens for patients eligible for T-DXd therapy. Patient and tumour characteristics and next-generation sequencing (NGS) data were correlated with HER2 IHC results.

RESULTS

166 patients with thoracic tumour samples had HER2 expression assessed: 46% were IHC 0, 28% IHC 1+, 13% IHC 2+ and 13% IHC 3+. HER2 IHC scores were overall lower for cytology cell blocks as compared with surgical pathology specimens; 79% of cases with paired specimens had a decrease in their HER2 IHC score from their surgical specimen to their paired cytology specimen. Of specimens with HER2 IHC 3+ and NGS available, only 14% (3/21) had concomitant ERBB2 alterations. Among all specimens, ERBB2 point mutations were noted in 4% (4/110) and ERBB2 amplification in 3% (3/110). The majority of HER2 3+ cases with paired NGS (17/21, 81%) had non-ERBB2 genomic alterations, including: KRAS, TP53, and STK11 mutations.

CONCLUSIONS

HER2 IHC 3+ is seen in a small but clinically significant proportion of samples and is associated with a variety of co-occurring non-ERBB2 genomic alterations. Preanalytical variables including specimen fixation can significantly impact the assessment of HER2 expression via immunohistochemistry.

Pericardial effusion cytology: malignancy rates, patterns of metastasis, comparison with pericardial window, and genomic correlates

INTRODUCTION

Cytologic evaluation of pericardial fluid is essential for diagnosing malignant pericardial effusions secondary to metastatic disease and for guiding appropriate clinical management; however, large cohort and up-to-date studies on malignancy rates and distribution of primary tumor sites is lacking.

MATERIALS AND METHODS

A retrospective analysis of pericardial fluid specimens from 2 large academic medical centers over a 10-year period was conducted. Clinical and specimen characteristics were correlated with cytologic diagnoses, and compared with surgical pathology pericardial specimens when available. In addition, genomic testing results were examined in a subset of malignant cases.

RESULTS

A total of 1667 pericardial fluid specimens were evaluated, with 15.3% diagnosed as malignant. Lung cancer (50.6%) was by far the most common primary tumor causing malignant pericardial effusions, followed by breast (13.0%), hematolymphoid (12.6%), and gastrointestinal (6.1%) cancers. A subset of patients with paired cytology and surgical pathology pericardial specimens showed concordance in 84.2% of cases, with discordant cases more frequently presenting with a positive cytology but negative surgical pathology result. Genomic analysis of a subset of malignant pericardial effusions revealed the most frequently mutated genes to be TP53, KRAS, CDKN2A/B, and PIK3CA, with a larger proportion of high tumor mutational burden (≥10 muts/Mb) in pericardial fluid samples compared to primary or metastatic sites.

CONCLUSIONS

While lung cancer is the most frequent cause of a cytology-confirmed malignant pericardial effusion, familiarity with relative frequencies of metastases from other sites can be particularly helpful, especially in the diagnostic work-up of an occult malignant pericardial effusion.

Comparison of three specimen collection techniques in tissue coagulum clot-based cell block preparation of endobronchial ultrasound-guided transbronchial needle aspiration

OBJECTIVES

The performance of cell blocks (CBs) can vary significantly depending on the specimen collection and processing techniques used. This study compared the efficiency of three distinct specimen collection methods for endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) samples.

MATERIALS AND METHODS

From June 2021 to June 2023, the study involved 1450 patients who underwent EBUS-TBNA, resulting in the sampling of 1941 lesions. For these samples, three distinct specimen processing methods were employed to prepare tissue coagulum clot-based CBs. Specifically, the filter paper method was employed in 470 cases (yielding 626 samples), the centrifugation method in 500 cases (yielding 673 samples), and the funnel filtration method in 480 cases (yielding 642 samples).

RESULTS

Out of these 1941 samples, the diagnostic yield for samples obtained using filter paper, centrifugation, and funnel filtration methods was 84.7 %, 87.7 %, and 92.5 %, respectively. In the subgroup of patients diagnosed with non-small cell lung cancer, the adequacy rate for molecular testing in samples processed through filter paper, centrifugation, and funnel filtration methods was 57.7 %, 82.0 %, and 88.3 %, respectively. In the centrifugation group, the combination of the CBs and cell pellet achieved an adequacy rate of 96.5 %.

DISCUSSION

The cellular yield of CBs from EBUS-TBNA was significantly enhanced using centrifugation and funnel filtration methods. The funnel filtration method offered a more convenient and cost-effective approach, reducing cellular loss due to sample dispersion in the fixative medium. The use of the centrifugation method to prepare CBs, along with the retrieval of cell pellets from the residual fixative medium, can maximize the specimen adequacy rate for molecular testing.

Advances in diagnostic liquid-based cytology

Liquid-based cytology (LBC) has changed the landscape of gynaecological cytology. A growing demand exists for LBC in diagnostic cytology, particularly for ancillary testing, such as immunocytochemistry and molecular testing. Ancillary testing solely based on conventional preparation (CP) methods remains challenging. Recently, the increased demand for specialist testing and minimally invasive techniques, such as endoscopic ultrasonography fine-needle aspiration, to obtain cellular samples has led to an increasing demand for ancillary testing on cytology LBC supernatant, slides and cell block (CB). This facilitates the diagnosis and prognosis in cytology samples enabling personalized treatment. An understanding of the history and future prospects of LBC is crucial for its application in routine diagnostics by cytopathologists and cytotechnologists. In this review, we initiated an internet search using the keyword 'liquid-based cytology', and we conducted a literature review to discuss the usefulness of combined diagnosis of LBC and CP, immunocytochemistry and molecular testing and assessed the quality of nucleic acids in diagnostic LBC. High-quality and cell-rich diagnostic LBC surpassed the CP method alone in terms of reliability and versatility of ancillary testing in cytological diagnosis. Conclusively, diagnostic LBC lends itself to various new technologies and is expected to continue evolving with innovations in the future.

[SFE-AFCE-SFMN 2022 consensus on the management of thyroid nodules: Interest and place of thyroid cytology]

The SFE-AFCE-SFMN 2022 consensus deals with the management of thyroid nodules, a symptom that is a frequent reason for consultation in endocrinology. Thyroid nodules are very common and mostly benign. Thyroid ultrasound and thyroid fine-needle aspiration biopsy (FNAB) are the reference tests for the analysis of these nodules. The aim of this article is to describe for the cytopathologist the key points of the SFE-AFCE-SFMN 2022 consensus involving thyroid cytology: the indications for thyroid FNAB, the technique and analysis, and the management (treatment, follow-up) following this cytological screening examination, a key element in the management of the thyroid nodule.

Cell blocks in cytology: review of preparation methods, advantages, and limitations

Cell blocks are cytologic preparations that are processed as paraffin embedded blocks in a manner comparable to formalin-fixed paraffin-embedded tissue in surgical pathology. In addition to serving as an adjunct to other cytologic preparations for morphologic diagnosis, cell blocks play an increasingly important role as they yield tissue sections that can be utilized for ancillary testing such as immunohistochemical stains and molecular studies. While essentially universally viewed as playing a pivotal role in cytopathology practice, there are various factors that limit their use in practice and contribute to dissatisfaction with cell block quality. Cell block preparation, as opposed to tissue processing in surgical pathology, is more variable with many different protocols in use today. This review explores the most commonly used cell block preparation techniques currently in use with review of the unique advantages and limitations each method presents. The goal of this work is to serve as a resource that can aid in making more informed decisions about which cell block protocol may work best for individual laboratories.

A novel method for making cell blocks with higher cellular yield

INTRODUCTION

Cytopathology is an important part of pathology that is used to diagnose disease on the cellular level. The application of the cell block (CB) technique plays a vital role in cytological diagnosis, as blocks and slides can be further used for special stains, immunohistochemistry (IHC), and molecular pathological analysis. Several methods for making CBs have been reported, but their procedures and cellular yield are still deemed unsatisfactory. In this article, we used gellan gum (GG) as an adjuvant for CBs, which resulted in higher cellular yield with simpler procedures.

METHODS

CBs were prepared by using GG, copper sulfate, plasma/thrombin, or pregelatinized starch methods. The procedures of each of these four methods were then compared. CB sections were stained with hematoxylin and eosin (H&E), and the background and morphological features seen by H&E staining were compared. A preliminary IHC and fluorescence in situ hybridization (FISH) study was performed using cytology specimens from eleven and five cases, respectively. The expression of immunocomplex by IHC and the molecular signals detected by FISH were compared in CB sections made by the four methods and a section derived from the biopsy specimen block from the same patient. Feulgen staining, Alcian blue staining, and Masson trichrome staining were performed on the CB sections from 3 cases of pleural fluid. The cellular yield of CB sections from 83 cases according to the four methods was compared using NDP analysis software.

RESULTS

The results demonstrated that sections derived from CBs made with GG had a clear background and good morphological features by H&E staining. The expression of immunocomplex by IHC and the molecular signals of FISH detection in the sections from CBs made by GG were accurately located just as those in biopsy sections from the same patient. The DNA, acidic mucus, and fibrin could be clearly identified through special stains in the CB sections. The procedures involved in the GG method were easily controllable and the coagulated gel increased the ease by which the CB was embedded and sectioned. Specifically, sections from CBs made by the GG method contained higher cellular yield because cells could be concentrated on the bottom of the gel after centrifugation.

CONCLUSION

This novel method for making CBs is a practical, simple method that can result in higher cellular yield. This method is therefore worth promoting in clinical applications.

SFE-AFCE-SFMN 2022 Consensus on the management of thyroid nodules : Recommendations in thyroid cytology: from technique to interpretation

The SFE-AFCE-SFMN 2022 consensus deals with the management of thyroid nodules, a condition that is a frequent reason for consultation in endocrinology. In more than 90% of cases, patients are euthyroid, with benign non-progressive nodules that do not warrant specific treatment. The clinician's objective is to detect malignant thyroid nodules at risk of recurrence and death, toxic nodules responsible for hyperthyroidism or compressive nodules warranting treatment. The diagnosis and treatment of thyroid nodules requires close collaboration between endocrinologists, nuclear medicine physicians and surgeons, but also involves other specialists. Therefore, this consensus statement was established jointly by 3 societies: the French Society of Endocrinology (SFE), French Association of Endocrine Surgery (AFCE) and French Society of Nuclear Medicine (SFMN); the various working groups included experts from other specialties (pathologists, radiologists, pediatricians, biologists, etc.). This section deals with the technique and interpretation of thyroid fine-needle aspiration biopsy (FNAB), a reference test for the analysis of thyroid nodules.

Impact of a Modified HistoGel Method for Processing Endocervical Curettage Specimens on Diagnostic Yield

OBJECTIVES

Endocervical curettage (ECC) specimens may be limited by scant tissue. We evaluated whether a cellular concentration processing method could improve their diagnostic quality.

METHODS

Between October 2018 and June 2019, ECC specimens were assigned chronologically to one of two groups: nonconcentrated ECC (NECC) or concentrated ECC (CECC). NECC specimens underwent routine histologic processing. CECC specimens were processed using a published HistoGel-based cell block method. We reviewed diagnoses for ECCs, concurrent cervical biopsies and/or loop electrosurgical excision procedures (LEEPs), and preceding Papanicolaou (Pap) smears. We performed multivariate logistic regression analyses to evaluate the impact of processing method on ECC adequacy and discordance between Pap smear and worst tissue diagnoses.

RESULTS

NECC and CECC adequacy was 88.2% and 84.7% (P = .06). ECC adequacy was greater if concurrent biopsy/LEEP was performed (odds ratio [OR] = 1.76, P < .01). Discordance between Pap smear and worst tissue diagnoses was 9.5% and 13.3% (P = .04) for cases with NECC and CECC processing, although processing method was not significant in multivariate analysis (OR = 0.74, P = .11). Adequate ECC sampling and concurrent biopsy/LEEP were independently associated with concordance between Pap smear and worst tissue diagnosis (OR = 0.46, P < .01 and OR = 0.65, P = .02).

CONCLUSIONS

ECC processing method did not significantly affect either specimen adequacy (P = .06) or diagnostic discordance (P = .11) when controlled for other factors.