Cytologic diagnosis of lung cancer. Principles and problems

This diagnostic seminar discusses the current status of the principles and problems of cytology as it is applied to the diagnosis of lung cancer. This discussion is divided into four major parts. Part I presents a discussion of cytopreparatory techniques and cytology of the lung in the absence of cancer. The cytology of benign proliferations which may mimic cancer is emphasized. The role of cytology in the diagnosis of pulmonary infectious organisms is noted. Part II discusses lung cancer as manifested in specimens of sputum, bronchial washings, and bronchial brushings. Part III presents some data on the validity of cytology with respect to role of specimen number and type in lung cancer diagnosis and cell typing in lung cancer. The continued usefulness and importance of multiple specimens of sputum for lung cancer diagnosis are documented. Part IV presents a brief synopsis of fine needle aspiration biopsy of lung cancer.     

Fine-needle aspiration as the initial diagnostic modality in malignant lung disease

Cytologic detection of lung cancer is accepted, accurate, and time-honored. Typically, cytologic workup of a radiologic abnormality proceeds sequentially from sputum to bronchoalveolar cytology, and, if necessary, to fine-needle aspiration biopsy (FNA). Initial use of FNA in lung cancer diagnosis is controversial, but increasingly popular. We therefore decided to objectively assess current practice in cytologic lung cancer diagnosis at our institution. All pulmonary cytologic diagnoses for 1993 and the first half of 1994 were retrieved. Positive diagnoses were then used to access all patient data. Patients were stratified according to the specimen from which the first positive diagnosis was obtained. Of 542 pulmonary cytology specimens, 15% were sputa, 65% were bronchoalveolar, and 20% were FNAs. One hundred sixty-one of 172 malignant diagnoses were first diagnoses. Three percent of first malignant diagnoses were made from sputa, 47% were from lavages, and 50% were from FNAs. Although FNAs comprised just 20% of all pulmonary cytologies, 50% of all new malignant cytologic diagnoses were made by FNA. Initial use of FNA is successful, has a high diagnostic yield and low complication rate, and offers the most direct approach to diagnosis. Diagn Cytopathol 1996;14:268–272. © 1996 Wiley-Liss, Inc.     

The value of cytology in the diagnostics of lung cancer

In order to elucidate the relative contributions made by cytology and histology in the diagnosis of lung cancer, we studied the cytology and histology reports of all patients who received a microscopic diagnosis of lung cancer in our hospital during the 7 years 1996-2002. This gave a total of 407 patients. The most frequent diagnoses were squamous cell carcinoma (34.9%), adenocarcinoma (24.8%), and small cell carcinoma (17.8%). One hundred and fifteen patients (28.3%) received their microscopic diagnosis based only on cytology, which therefore proved to be of great diagnostic value. The most useful type of cytology specimen was taken by bronchial lavage or bronchial brushing. These types of specimens provided the diagnosis in 71 patients (17.4%). Cytology was especially capable of finding squamous cell carcinomas. Small cell carcinomas were underrepresented (9.6% versus 17.8%) and unspecified carcinomas greatly overrepresented (9.6% versus 2.9%) among the diagnoses obtained by cytology alone. We conclude that cytology is of considerable diagnostic value, although not as specific as histology for the subtyping of carcinomas. Clinicians should be more aware of the usefulness of cytology, especially in cases where it is difficult to obtain bronchoscopic biopsy samples for histological examination.     

Rinse fluid and imprint smear cytology of bronchial biopsies in diagnosis of lung tumors

The usefulness of rinse fluid and imprint smear cytology of the bronchial biopsy has been studied in diagnosis of lung cancer. However, scarce data is available regarding rinse fluid cytology of biopsy. The aim of this study was to evaluate these cytologic techniques for their diagnostic accuracy. Bronchial biopsy was taken in 52 patients clinically/radiologically suspected to have lung carcinoma. Imprint smears of the biopsy were prepared, following which it was put in balanced saline solution to collect rinse fluid of biopsy before transferring it to formalin for fixation. Cytological diagnosis from imprint and rinse fluid smears was compared with histopathological diagnosis. Malignancy was detected in 45 cases of 52 patients on histopathology. Positive result was given by rinse fluid cytology in 34 (65.4%) cases while diagnostic accuracy was 78.8%. The imprint smears were positive for malignancy in 44 (84.6%) cases with diagnostic accuracy of 98.08%. There were no false-positive results, but one case was incorrectly typed by both the techniques. Imprint smear cytology has a better diagnostic accuracy and efficacy over rinse fluid while the two cytologic techniques can be used in combination routinely with biopsy to provide an early and reliable diagnosis in lung cancer.     

Endobronchial ultrasound‐guided fine‐needle aspiration cytology of bronchial low‐grade mucoepidermoid carcinoma: Rapid on‐site evaluation of cytopathologic findings

Bronchial mucoepidermoid carcinoma (MEC) is rare, comprising about 0.2% of primary lung tumors. Endobronchial ultrasound (EBUS) guided fine‐needle aspiration (FNA) cytology is an integral tool in the diagnosis and staging of malignant lung tumors. Rapid on‐site evaluation (ROSE) has been proven useful as a guide for assessing the adequacy and accuracy of the FNA samples. Therefore, comprehensive knowledge of diagnostic cytomorphologic findings of MEC is critical for ROSE. We reported a 46‐year‐old woman with 6 weeks of cough productive of yellow sputum that did not improve on antibiotics. A chest CT demonstrated a well‐circumscribed nodule in the right lower lobe bronchus that extended into the lung parenchyma. EBUS‐guided FNA was performed to obtain diagnostic materials. The ROSE of cytology specimen revealed numerous tight clusters of cells with well‐defined, but scant cytoplasm. These cells were relatively small and bland with high N/C ratio, resembling benign ductal cells. Neither cilia nor intranuclear inclusions were noted. Focal extracellular metachromatic mucinous materials were also noted. A preliminary diagnosis of “low‐grade epithelial neoplasm, favor low grade MEC” was rendered. The definitive diagnosis was confirmed by both cytology and core biopsy. EBUS‐guided FNA cytology can be a reliable method for the diagnosis of bronchial low grade MEC. The cyto‐morphology of ROSE can indicate the diagnosis of low grade MEC and direct the appropriate follow‐up triage of the specimen.Diagn. Cytopathol. 2013;41:1096–1099. © 2012 Wiley Periodicals, Inc.     

Fine‐needle aspiration cytology of non‐small cell lung carcinoma: A paradigm shift

Lung carcinoma is one of the commonest causes of cancer related death. Fine‐needle aspiration cytology (FNAC) is a well‐established technique in the diagnosis of various malignant tumors. FNAC is now an important technique in classifying lung carcinomas and also detecting salient mutational changes in lung carcinomas. The judicious use of the various immunological markers such as TTF‐1, p40, CK 5/6, CK 7 and Napsin may help in sub‐classification of non‐small cell lung carcinomas (NSCLC). The mutational changes in epidermal growth factor receptor (EGFR) and ALK genes are needed in targeted therapy of adenocarcinoma of lung. With the help of immunocytochemistry, polymerase chain receptor, fluorescent in situ hybridization and next generation sequencing, one can detect various mutational changes in NSCLC. In this review article, we have discussed the role of cytology and other ancillary techniques to classify lung carcinomas. The important mutational changes in lung carcinoma for targeted therapy have also been discussed in detail.     

Percutaneous fine-needle cytology for lung cancer diagnosis

The authors have performed 1,758 needle cytology procedures since 1966 in cases suspected of lung cancer. The results of percutaneous aspiration fine-needle cytology in 232 patients with lung cancer lesions between January 1973 and August 1984 are discussed. Of the 232 cases, lung cancer was diagnosed in 211 cases by this needle cytology technique. This procedure was performed only in peripheral tumors. Positive diagnosis was obtained in 32 out of 36 cases (88.89%) of tumors less than 2 cm in diameter and 179 out 196 cases (91.33%) 2 cm or more in diameter. Twenty-one cases showed false-negative results for malignant diagnosis. There were two false-positive cases, which were resected on a diagnosis of lung cancer that was later revised to inflammatory lesions. The specimens were apparently obtained from areas of severely atypical squamous metaplastic cells. Among 1,758 procedures, 209 complications were observed. In conclusion, for the diagnosis of peripheral lung cancer, percutaneous needle cytology yields a high degree of diagnostic accuracy and is safe, rapid, and economical.     

Fluoreszenz-in-situ-Hybridisierung

Fluorescence in situ hybridization (FISH) is a powerful method for the identification of chromosomal aberrations to improve the diagnostic performance of cytology. FISH is applicable to almost any type of cytological specimen irrespective of cell type, staining or fixation modality. Multi-target tests for the simultaneous analysis of four chromosomes or chromosomal loci improves the sensitivity of cytological diagnosis in bladder and lung cancer and is most helpful in equivocal cytology. FISH also allows a reliable distinction between malignant mesothelioma and reactive mesothelial cells. Specific translocations can easily be detected by FISH for precise diagnosis of lymphomas and sarcomas. Testing for HER-2 amplification has become a standard method to select patients with breast cancer for therapy with trastuzumab. Co-analysis of HPV and selected genes could become a useful approach in gynecological cytology. The spectrum of diagnostic FISH applications is continuously growing.     

Endobronchial ultrasound-guided fine-needle aspiration and liquid-based thin-layer cytology

BACKGROUND: Optimal management of patients with lung cancer requires accurate cell typing of tumours and staging at the time of diagnosis. Endobronchial ultrasound-guided lymph node aspiration as a method of diagnosing and staging lung cancer is a relatively new technique. AIM: To report the use of liquid-based-thin-layer cytology for the processing and reporting of these specimens. METHODS: The specimens obtained from 80 patients were processed using the ThinPrep system, with the remainder of the samples being processed as a cell block. RESULTS: 40 of the 81 procedures yielded malignant cells (30 non-small cell carcinoma, 8 small-cell carcinoma and 2 combined small-cell carcinoma/non-small-cell carcinoma). The cell blocks were found to contain sufficient material to allow the immunohistochemical characterisation of tumour cells with a range of antibodies. CONCLUSION: The use of liquid-based-thin-layer cytological techniques provides high-quality specimens for diagnostic purposes. When used in conjunction with cell blocks, sufficient material may be obtained to allow immunohistochemical studies to confirm the tumour cell type. Given the current move towards centralisation of pathology services, this approach gives the pathologist high-quality specimens without the need for direct onsite support at the time of the procedure.     

Ciliated muconodular papillary tumors of the lung: Cytologic features and diagnostic pitfalls in intraoperative examinations

Ciliated muconodular papillary tumors (CMPTs) of the lung are rare, likely benign neoplastic lesions. Here we describe a case of a CMPT, focusing on its cytologic features, which to our knowledge have not been reported previously. Owing to dull back pain, a 69‐year‐old male non‐smoker underwent CT, which revealed a 1.3 × 1.3‐cm solid nodule in the peripheral field of the left lower lung lobe. A wedge resection of the nodule was performed, with the provisional diagnosis being primary lung cancer. Macroscopic examination of a resected specimen showed a 1.2‐cm grayish nodule. Touch imprint smear cytology revealed ciliated columnar cells and mucous cells, as well as abundant extracellular mucin on inflammatory background of lymphocytes and histiocytes. Histologic examination revealed a nodular papillary tumor composed of ciliated columnar cells, mucous cells, and basal cells surrounded by a mucin pool. No nuclear atypia or mitotic figures were identified. The final diagnosis was CMPT. The postoperative course was uneventful, with no recurrence at 8 months after surgery. Although a CMPT is a rare lung tumor, it should be considered when cytological or histological examination of a solitary peripheral lung nodule shows non‐atypical ciliated cells and mucous cells surrounded by mucin.     

Advanced imaging technology applications in cytology

Novel techniques have been developed to image cells at cellular and subcellular levels. They allow images to be analyzed with ultra‐high resolution, in 2D and/or 3D. Several of these tools have been tested on cytology specimens demonstrating emerging applications that are likely to change the field of cytopathology. This review covers several of these advanced imaging methods. The use of optical coherence tomography to perform optical biopsies during endoscopic ultrasound procedures or visualize cells within effusion samples is discussed. The potential for quantitative phase microscopy to accurately screen Pap test slides or resolve indeterminate diagnoses in urine cytology is reviewed. The article also examines the application of 3D cytology using LuCED for lung cancer detection in sputum samples and the feasibility of imaging flow and mass cytometry to measure multiple biomarkers at the single cell level. Although these novel technologies have great potential, further research is necessary to validate their routine use in cytopathology practice.     

Papillary transitional-cell carcinoma of the upper urinary tract: a cytological review

Urinary cytology is a well-accepted diagnostic procedure for bladder carcinomas but it is utilized less frequently for diagnosis of upper urinary tract tumors. Accurate diagnosis depends on a suitable specimen as well as knowledge of diagnostic traps. This review article with several case studies emphasizes the various techniques used to obtain optimal samples, correct interpretative criteria, and diagnostic pitfalls. Technological advances for objective grading and predicting the biological behavior of tumors are also discussed.     

Molecular/biomarker testing in lung cytology: A practical approach

The increasing comprehension of molecular mechanisms underlying lung cancer and the discovery of targetable genomic alterations has dramatically change the pathological approach to lung cancer, especially non-small cell lung cancer (NSCLC). This unstoppable knowledge has taken pathologists to the leading front on lung cancer management. This is especially relevant in the world of cytopathology where “doing more with less” is a daily challenge. Nowadays with a growing number of predictive biomarkers needed to manage patients with NSCLC, there has been a paradigm shift in care and handling of diagnostic samples. One of the main emphasis and interest relies on the utilization of cytologic samples and small biopsies for not only diagnostic purposes but also for ancillary testing. Moreover, lung cytopathology is in continuous evolutions with implementation of new diagnostic techniques, new tools, and facing new challenges. The goal of this paper will be to provide the reader with the necessary concepts than can be used to exploit the cytological samples in order to use these samples for comprehensive diagnosis and relevant ancillary testing purposes.     

Fluorescence in situ hybridization (fish): A user's guide to optimal preparation of cytologic specimens

Fluorescence in situ hybridization (FISH) is a reliable method for tagging centromeric regions of specific chromosomes in interphase nuclei. Not only is FISH useful for chromosome enumeration, but as region-specific chromosome probes are developed, the clinical applications and potentials for use by pathologists are extensive. This technique lends itself particularly to use in cytology preparations because the cells are disaggregated and monolayer preparations yield excellent technical hybridization results. Over a 7-mo period we processed cytologic samples in an attempt to define and outline a method for optimal specimen processing for FISH use in cell suspensions, techniques applicable to all fresh cytology specimens which can also be used for the processing of surgical pathology aspirates and other material. All samples should be promptly processed to ensure specimen viability, and triaged on an individual basis to ensure preparation of moderately cellular monolayered cytospins. Equivalent nuclear probe signals have been obtained with several sample fixation methods air-drying, 95% ethanol, methanol (Diff-Quik fixative), and Carnoy's solution. No difference was noted in the nuclear probe signals or specimen adhesion on positively charged or noncharged slides. After initial fixation our slides remained at room temperature until FISH was performed, without any adverse effects. A short digestion with proteinase K and subsequent rehybridization yielded positive results on samples that originally yielded poor nuclear probe signals. © 1995 Wiley-Liss, Inc.     

Automated cytology. The state of the art

Analytical cytology is the science of automatically analyzing morphologic, biochemical, biophysical, and functional aspects of cells by machine. Two basic techniques are used: image cytometry, in which microscopic objects on a slide or in a photograph are analyzed; and flow cytometry, in which biologic particles in aqueous suspensions are forced to pass through a measuring device. The latter technique has the added power of sorting particles according to type for further study. Currently, analytic cytology is being studied for use in the following areas: WBC differentiation, cell-cycle kinetics, prescreening for uterine cancer, screening of high-risk groups, monitoring of tumor therapy, and microbial and chromosome analysis. In all these areas, analytic cytology has the potential to improve existing techniques and to make results more uniform; likewise, its sensitivity, accuracy, and speed may well allow a breadth and depth of analysis not presently allowed by human study.     

EGFR analysis: Current evidence and future directions

Until a few years ago, only lung cancer histological specimens were considered suitable for testing epidermal growth factor receptor (EGFR) mutations. Then, several retrospective studies were designed to test EGFR mutation on a sizeable number of parallel cytological and histological samples obtained from the same patients and, even more recently, several institutions reported their prospective clinical experiences on routine specimens. Basing on these studies the College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology have recently considered cytological samples suitable for EGFR testing. Therefore, it seems timely to draw together the threads of this large body of information in order that cytopathologists can be knowledgeable partners in the multidisciplinary process of targeted cancer therapy and to help refine current testing guidelines. This review addresses (1) the more common proposed techniques including the use of direct cytologic smears cell blocks and liquid based cytology; (2) the issues related to current practice, which in Europe is external centralized testing that is usually done on samples containing very few cells; and (3) the future directions based on the implementation on lung cytology of next generation sequencing approaches. Diagn. Cytopathol. 2014;42:984–992. © 2014 Wiley Periodicals, Inc.     

Recent advances in thin-layer cytology.

In recent years liquid-based cytology has emerged as an alternative to conventional cytopreparatory methods. In particular, the ThinPrep system has found broad acceptance in non-gynecologic cytopreparation. Many laboratories have successfully applied this technique to body fluids (e.g. urine, pleural effusions), brushing samples (e.g. gastrointestinal tract, lung) and fine-needle aspiration. Most comparative studies have shown the ThinPrep system to perform as well as or better than conventional preparations in non-gynecologic cytology; plus, the residual cells within the vial can be used for DNA analysis or immunohistochemical and other special studies. Recently, the ThinPrep 2000 system has been approved for use in gynecologic cytology. This approval was based on a large, multicenter clinical study that showed the ThinPrep system to be favored over the conventional Pap smear for the detection of low-grade squamous intraepithelial lesions, or more severe lesions. At screening centers the improved rate of detecting low grade squamous intraepithelial lesions (LSIL) or more severe diagnosis was up to 73%, with an average improvement of 65% as compared to the conventional Pap smears. Also, for specimen adequacy, the ThinPrep method was statistically favored over conventional cytology methods. This multicenter clinical trial demonstrates the ThinPrep 2000 system was more effective than the conventional Pap smear for the detection of atypical cells and cervical cancer and its precursor lesions. In addition, by collecting cells in a liquid-based medium the opportunity is present to improve the Pap test by adjunctive testing for Human Papilloma Virus or other procedures. This creates the opportunity for improved triage and management of patients with cervical abnormalities. Diagn. Cytopathol. 1998;18:24–32. © 1998 Wiley-Liss, Inc.     

Immunohistochemistry in cytologic diagnosis using fine needle aspiration

The role of immunocytochemistry in fine-needle aspiration cytology. The Authors review the literature about fine-needle aspiration biopsy cytology in different organs and show the feasibility of the application to cytological specimen of immunocytochemical methods. Thus, they analyze 15 cases of tumors of various localization diagnosed by F.N.A.C. where immunocytochemistry succeeded in their correct typization. They also show the encouraging results of the immunocytochemical search of specific hormones in pituitary adenomas. Therefore the Authors emphasize the great usefulness of immunocytochemical techniques for the improvement of the diagnostic possibilities in the fine-needle aspiration cytology.     

Amebic lung abscess with coexisting lung adenocarcinoma: a unusual case of amebiasis

Amebic lung abscess with concurrent lung cancer, but without either a liver abscess or amebic colitis, is extremely uncommon. Here, we report a 70-year-old man presenting with pulmonary amebiasis and coexisting lung adenocarcinoma. During his first-time hospitalization, the diagnosis of lung amebiasis was confirmed by morphological observation and PCR in formalin-fixed and paraffin-embedded sediments of pleural effusion. Almost four months later, the patient was readmitted to hospital for similar complaints. On readmission, lung adenocarcinoma was diagnosed by liquid-based sputum cytology and thought to be delayed because coexisting amebic lung abscess. This case demonstrated that sediments of pleural effusion may be used for further pathological examination after routine cytology has shown negative results. At the same time, we concluded that lung cancer may easily go undetected in the patients with pulmonary amebiasis and repetitive evaluation by cytology and imaging follow-up are useful to find potential cancer.