Diagnostic value of clot examination for malignant cells in serous effusions

EGFR testing in paraffin-embedded cell block cytology material is reliable with increased detection for effusion fluid

INTRODUCTION

Cytology is integral to lung cancer diagnosis. Aspiration and exfoliative fluid specimens represent valuable tumor material for molecular testing. In this study, a large retrospective cohort of EGFR tests was reviewed to address the adequacy, detection and discrepancy rate in tests performed with cytology material.

METHODS

EGFR tests performed from 2013 to 2022 were reviewed and classified by the modality of obtaining tissue and by tissue type. EGFR tests for tissue specimens were performed on unstained sections of paraffin-embedded material on glass slides. Adequacy and types of mutation(s) detected were analysed. Cases where multiple EGFR testing was performed on the same patient were reviewed for discordance.

RESULTS

There were 5,504 tests retrieved, with 1,855, 3,607 and 42 performed on cytology, surgical and blood specimens. Lung and excision specimens were more often adequate (p < 0.001). Cytology material showed lower adequacy rates (p < 0.01). EGFR detection (positive) rate was higher in pleural fluid compared to biopsy (59.8 % vs 50.7 %, p = 0.022), but similar between lung and lymph node cytology and non-cytology specimens. Effusion fluid specimens had the highest adequacy (81.5 %) and detection rate (59.3 %) among cytology specimens (p < 0.001). Four (4.4 %) cases showed discordant results in cytology specimens. Two were false negatives in the non-cytology material. Only in one case was cytology material genuinely discrepant. The remaining discordance was attributed to the interval treatment effect.

CONCLUSION

The findings support that EGFR testing in cell block is reliable and complements tissue material. In addition, pleural fluid appears to be superior to pleural biopsies for molecular testing.

Architectural aspects of cell-blocks as small biopsies

Cell-block preparations have become an essential part of integrated cytology diagnosis. They are essentially microbiopsies that are formalin fixed and embedded in paraffin. This has become more prevalent with greater sample procurement due to the advent of newer biopsy techniques and needles. Cell-blocks allow retrieval of small tissue fragments from cytology specimens that sometimes cannot be processed by alternate cytologic techniques. They represent concentrated, cell-enriched preparations that provide cytologists with the opportunity to evaluate cellular architecture, as well as to perform ancillary testing. A cell-block compatible sample may thus obviate the need for a more invasive procedure such as a tissue biopsy. Microscopic examination of cell-blocks is quick, avoids obscuring material, permits cells to be evaluated in one focal plane, and allows the histologic architecture such as glandular differentiation, papillary formations, and sometimes invasion to be easily identified. This new era of “cytohistology” accordingly requires practicing cytologists to become more familiar with histopathology. This review article discusses the benefit of various architectural patterns identifiable in cell-blocks employed as an adjunct to Pap tests, exfoliative fluid specimens, and fine-needle aspirations.

[Clinical Value of Cell Block in the Diagnosis of Malignant Pleural Effusion]

背景与目的

恶性胸腔积液（malignant pleural effusion, MPE）是原发于胸膜或转移至胸膜的恶性肿瘤造成的胸腔积液。MPE患者预后差，应在减少病人痛苦的前提下，准确而快速的明确MPE的性质及病因，为后续治疗提供有效依据。

方法

103例患者应用自然静止法或血凝集法制得胸水沉淀物，结合HE染色及免疫组化染色，在诊断MPE上与其他方法相比较。

结果

103例MPE中，胸腔积液沉淀物方法确诊90例（诊断率87.4%）；32例仅通过沉淀物诊断，74例指出病理类型，23例明确原发灶；与71例同时行有创方法比较，诊断率为81.7%与87.3%；对比液基细胞学，检出率为86.7%和44.0%。

结论

胸腔积液沉淀物方法不仅可以增加细胞学诊断率且与其他有创方法诊断率近乎一致，同样可确定MPE病理类型及原发灶，是有创方法的较佳补充，甚至对于部分患者胸水沉淀物是唯一确诊方法。

Utility of cell blocks obtained by catheter aspiration via a guide sheath during endobronchial ultrasonography

BACKGROUND

The demand for adequate tissue samples for both morphological assessment and molecular studies on lung cancer treatment has increased. The aim of this study was to evaluate whether cell blocks (CBs) prepared from endobronchial ultrasonography with guide sheath (EBUS-GS) rinsing following catheter aspiration provide additional information.

METHODS

We produced CBs from rinse fluid obtained from washing the inside of the sheath with saline after conventional EBUS-GS between May 2012 and April 2013. During the first 7 months, the sheath was aspirated with 20mL of negative pressure while moving the catheter back and forth [aspiration group (Asp)]. During the next 5 months, the sheath was not aspirated, but only rinsed out [conventional group (Con)]. Patients diagnosed with lung cancer by EBUS-GS and/or CBs were identified and evaluated. The diagnostic rate of each sampling method was compared between the two groups. The number of tumor cells was also compared between the CB and EBUS-guided transbronchial lung biopsy (EBUS-TBB) groups.

RESULTS

EBUS-GS was performed on 113 patients. Fifty-five patients were included in this study (Asp=30, Con=25). The diagnostic yield of CBs in Asp was higher than that in Con (56.7% vs 32.0%; p=0.06). Asp showed no significant difference in the number of tumor cells between CB and EBUS-TBB. One patient who showed negative EBUS-TBB pathological results but positive CB results was diagnosed only by immunohistological staining of CB.

CONCLUSION

CB prepared from EBUS-GS rinsing following catheter aspiration may provide additional information.

[Value of Cell Block in the Diagnosis of Malignant Pleural Effusion]

背景与目的  恶性胸腔积液(malignant pleural effusion, MPE)是由原发于胸膜的恶性肿瘤或者是转移至胸膜的恶性肿瘤造成的胸腔积液。对于不明原因的单侧胸腔积液, 首要任务是排除或者是确诊恶性胸腔积液。胸腔积液沉淀物是将送检胸腔积液细胞学剩余的胸腔积液进行离心或者是自然静置所获得的细胞块。此技术具有操作简单、有创性小、重复性高、对恶性胸腔积液的诊断率相对较高等特点, 在恶性胸腔积液的诊断、治疗等方面起着重要的作用。本文主要从沉淀物的制作方法、免疫组织化学染色检查的鉴别诊断价值、沉淀物的诊断优势及沉淀物行基因检测的临床应用价值等方面来论述胸腔积液沉淀物对恶性胸腔积液的诊断价值。

Pleural effusion of malignant aetiology: cell block technique to establish the diagnosis

We describe cases of two previously healthy women presenting with progressively worsening breathlessness for 1-2 months. In both cases, physical examination was suggestive of a left-sided pleural effusion, confirmed by chest X-ray. Analysis of aspirated fluid showed a lymphocytic exudate, but cytological analysis was negative for malignancy in both patients. CT scan revealed malignancies as the underlying cause of the effusions. Both patients were managed with intercostal drainage in order to collect a sufficient amount of pleural fluid to perform a new technique in our hospital: cell block. This proved to be extremely useful in assessing the definitive diagnosis and management of both women. We briefly discuss the approach to a malignant pleural effusion and the aid of this not-so-new technique.

An improved high-output cell microarray technology

AIMS

Cell microarray (CMA) is a high-throughput scientific research tool, which has greatly accelerated many analyses based at the cellular level. However, there are few described methods for constructing CMAs. Here, we introduce a new, simple, high-output CMA method that is applicable to a broad range of cellular samples.

METHODS

In this method, a recipient block (length, 3.6 cm; width, 2.7 cm; depth, 2 cm) with 40 dot markers was moulded using a transparent plastic box. Adenocarcinoma cells were collected from malignant pleural effusions, cell cylinders were moulded with plastic piping and the cylinders were manually arrayed one by one into the corresponding location of the 60 °C pre-softened recipient block using the guide holes drilled with a steel needle. We constructed a 40-cylinder CMA to prove this method. The expression of cytokeratin 7 (CK7) in the CMA was examined to confirm antigen preservation and epidermal growth factor receptor (EGFR) gene mutation was screened for in five samples.

RESULTS

The CMA prepared by this method had well-defined array configurations, good cellular morphology and well-preserved proteins and DNA. A total of 1000 sections could be easily gained from this CMA block.

CONCLUSIONS

This simple and low-cost method provides a novel way of preparing a high-output CMA.