Cytopathology of pulmonary adenocarcinoma with a single histological pattern using the proposed International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society (IASLC/ATS/ERS) classification

Invasion and Grading of Pulmonary Non-Mucinous Adenocarcinoma

Lung adenocarcinoma staging and grading were recently updated to reflect the link between histologic growth patterns and outcomes. The lepidic growth pattern is regarded as "in-situ," whereas all other patterns are regarded as invasive, though with stratification. Solid, micropapillary, and complex glandular patterns are associated with worse prognosis than papillary and acinar patterns. These recent changes have improved prognostic stratification. However, multiple pitfalls exist in measuring invasive size and in classifying lung adenocarcinoma growth patterns. Awareness of these limitations and recommended practices will help the pathology community achieve consistent prognostic performance and potentially contribute to improved patient management.

Second opinion for pulmonary and pleural cytology is valuable for patient care

INTRODUCTION

Thoracic cytology can be challenging due to limited procured material or overlapping morphology between benign and malignant entities. In such cases, expert consultation might be sought. This study aimed to characterize all pulmonary and pleural cytology consult cases submitted to our practice and provide recommendations on approaching difficult cases.

MATERIALS AND METHODS

All thoracic (pulmonary and pleural) cytology cases submitted for expert consultation to the University of Michigan (MLabs) from 2013 to mid-2022 were reviewed. Cases where cytology was only part of a hematopathology or surgical pathology consult were excluded. Patient demographics, specimen location, procedure performed, referring diagnosis, and our diagnoses were recorded for each case. Diagnoses were categorized according to the Papanicolaou Society of Cytopathology recommendations for pulmonary and effusion cytology. Discordant diagnoses were stratified as major or minor. Data was analyzed using chi-square analysis and logistic models.

RESULTS

We received 784 thoracic cytology consult cases, including 530 exfoliative samples and 307 fine-needle aspirations. The most common anatomic locations sampled were the bronchial wall (n = 194, 23%), lung nodule (n = 322, 38%), and pleura (n = 296, 35%). 413 cases had a diagnostic discrepancy (48.3%), with 274 (66%) minor and 139 (34%) major discrepancies. By location, pleural effusion specimens had the highest probability of a discrepant diagnosis (P = 0.003). By specimen type, fine-needle aspiration samples were significantly more likely to have a discrepant diagnosis (P = 0.06).

CONCLUSION

Nearly half of the thoracic cytology cases submitted for expert second opinion had diagnostic discrepancies. Consequently, consulting a tertiary medical care center with cytopathology expertise for challenging thoracic cytology diagnoses is beneficial.

Updates on lung adenocarcinoma: invasive size, grading and STAS

Advancements in the classification of lung adenocarcinoma have resulted in significant changes in pathological reporting. The eighth edition of the tumour-node-metastasis (TNM) staging guidelines calls for the use of invasive size in staging in place of total tumour size. This shift improves prognostic stratification and requires a more nuanced approach to tumour measurements in challenging situations. Similarly, the adoption of new grading criteria based on the predominant and highest-grade pattern proposed by the International Association for the Study of Lung Cancer (IASLC) shows improved prognostication, and therefore clinical utility, relative to previous grading systems. Spread through airspaces (STAS) is a form of tumour invasion involving tumour cells spreading through the airspaces, which has been highly researched in recent years. This review discusses updates in pathological T staging, adenocarcinoma grading and STAS and illustrates the utility and limitations of current concepts in lung adenocarcinoma.

Thoracic SMARCA4-deficient undifferentiated tumor with associated granulomatous reaction and response to pembrolizumab

Thoracic SMARCA4-deficient undifferentiated tumor (SMARCA4-UT) is a rare entity that was recently described in the current World Health Organization Classification of Tumors. These lesions are highly aggressive with dismal prognosis, and most patients present with metastasis at the time of diagnosis. While there are about 100 cases of SMARCA4-UT described in the literature, there are only few existing reports that describe the cytomorphology of these lesions. We present a patient with masses involving the mediastinum, right lung, right supraclavicular lymph node and right adrenal gland. Subsequent core-needle biopsy of the right supraclavicular lymph node showed epithelioid to pleomorphic tumor cells with prominent nucleoli and associated granulomatous inflammation. The tumor cells were positive for CD34 and synaptophysin, and were negative for cytokeratins. SMARCA4 and SMARCA2 both showed loss of expression, which led to the diagnosis of SMARCA4-UT. The patient underwent treatment with pembrolizumab (PD-1 blocker), carboplatin, etoposide, and radiotherapy, resulting in an almost 55% reduction in the size of the primary tumor. Our case illustrates that an associated granulomatous inflammation might be an uncommon presentation of an already rare malignancy, and awareness of this phenomenon would prevent from mistaking SMARCA4-UT for other more well-known entities that can present with granulomas.

Three-dimensional structural analysis of papillary thyroid carcinoma nuclei with serial block-face scanning electron microscopy (SBF-SEM)

Nuclear morphology of carcinoma cells is critical for the pathological diagnosis of papillary thyroid carcinoma (PTC). However, three-dimensional architecture of PTC nuclei is still elusive. In this study, we analyzed the three-dimensional ultrastructure of PTC nuclei using serial block-face scanning electron microscopy which takes advantage of the high-throughput acquisition of serial electron microscopic images and three-dimensional reconstruction of subcellular structures. En bloc-stained and resin-embedded specimens were prepared from surgically removed PTCs and normal thyroid tissues. We acquired two-dimensional images from serial block-face scanning electron microscopy and reconstructed three-dimensional nuclear structures. Quantitative comparisons showed that the nuclei of carcinoma cells were larger and more complex than those of normal follicular cells. The three-dimensional reconstruction of carcinoma nuclei divided intranuclear cytoplasmic inclusions into "open intranuclear cytoplasmic inclusions" connecting to cytoplasm outside the nucleus and "closed intranuclear cytoplasmic inclusions" without that connection. Cytoplasm with abundant organelles was observed in open inclusions, but closed inclusions contained fewer organelles with or without degeneration. Granules with a dense core were only observed in closed inclusions. Our observations suggested that open inclusions originate from nuclear invaginations, and disconnection from cytoplasm leads to closed inclusions.

Cytological features of stromal spindle cells and their prognostic significance in lung adenocarcinoma

INTRODUCTION

Cancer-associated fibroblasts (CAFs) in the tumour microenvironment play a key role in tumour development, proliferation, invasion, and metastasis. The cytological features of spindle cells including CAFs-defined as stromal spindle cells (SSCs) adjacent to cancer cells-are frequently encountered in pulmonary adenocarcinomas. This study aimed to investigate the association between the presence of SSCs in cytological specimens and the clinicopathological features.

METHODS

We evaluated 211 patients with pulmonary adenocarcinoma who underwent surgical resection. All participants had cytological specimens corresponding to the histological specimens available for review.

RESULTS

Of the 211 cases examined, 89 were SSC-positive (SSC+ ) and 122 were SSC-negative (SSC- ). SSC+ cases were more frequently associated with higher pathological stage (P < 0.001), lymph node metastasis (P = 0.002), anaplastic lymphoma kinase (ALK) gene rearrangement (P = 0.04), high tumour grade (P < 0.001), solid and micropapillary predominant pattern (P = 0.02), and lymphatic vessel (P = 0.003), blood vessel (P < 0.001), and pleural invasion (P = 0.03) as compared to SSC- cases. Patients with SSC+ adenocarcinoma had a significantly shorter recurrence-free survival than those with SSC- adenocarcinoma (P = 0.009). Cytologically, necrotic background (P = 0.002), mucinous cancer cells (P = 0.02), pleomorphic cells (P < 0.001), and mutual cell inclusions (P = 0.01) were observed more frequently in SSC+ adenocarcinomas.

CONCLUSIONS

The presence of SSCs could be an important cytological feature for predicting poor prognosis in lung adenocarcinomas.

Scrape cytology and radiological solid size correlation can be used in the intraoperative management of subsolid lung nodules

BACKGROUND

The term radiologic subsolid lung nodule (SLN) represents a heterogeneous group of non-neoplastic and neoplastic lesions. Intraoperative evaluation (IO) is often required to differentiate and diagnose. The current study aims to investigate the feasibility and reliability of scrape cytology (SC) and radiologic solid size correlation for the IO diagnosis of SLNs.

METHODS

Sixty-eight patients with SLN signs were eligible to take part in the study due to intraoperatively prepared SC slides. We managed to complete the blind radiologic solid size measurement and cytologic evaluation retrospectively. Cases were grouped into three categories based on their cytological features: Group-0 (Benign), Group-1 (mild atypical features), and Group-2 (severe atypical features/unequivocally carcinoma). IO diagnoses were given by combining the radiologic solid size and cytological findings.

RESULTS

Cytological features of Group-1 were observed in 100%, 93%, 32.5%, and 17% of the AIS, MIA, IA, and benign lesions, respectively. Cytological features of Group-2 were observed in 67.5%, and 7% of the IA and MIA, respectively. By combining cytology with radiologic solid size, 100%, 85%, 71%, and 83% of the AIS, IA, MIA, and benign lesions respectively were diagnosed correctly. Fifteen (15%) percent of the IA cases were underdiagnosed as MIA since their radiological solid sizes were less than 0.5 cm with cytological features of Group-1. Conversely, 29% of the MIA cases were overdiagnosed as IA since their radiological solid sizes were greater than 0.5 cm.

CONCLUSION

SLNs should be handled with caution in terms of IO management. SC and radiologic solid size correlation both provide a practical and tissue-protecting approach for the IO evaluation of SLNs, ensuring a high consistency between IO and definitive diagnosis.

Cytological characteristics of histological types of lung cancer by cytomorphometric and flow cytometric analyses using liquid-based cytology materials

BACKGROUND

Distinguishing the histological types of lung cancer is essential for determining treatment strategies in clinical practice. In this study, cytomorphological characteristics and proliferative activities were compared among histological types of lung cancer by cytomorphometric and flow cytometric analyses using liquid-based cytology (LBC) samples.

METHODS

Scraped LBC samples from 73 surgically resected specimens were collected between August 2018 and November 2019. Papanicolaou-stained and paired Ki-67-stained slides were used for cytomorphometric analyses. Another sample for each case was analyzed using a flow cytometric system (LC-1000). The cell proliferation index (CPIx) was calculated to evaluate proliferative activity.

RESULTS

In total, 73 cases, including cases of adenocarcinoma (n = 53), squamous cell carcinoma (n = 14), small cell carcinoma (n = 1), large cell neuroendocrine carcinoma (NEC; n = 3), and pleomorphic carcinoma (n = 2) were evaluated. Small cell carcinoma and large cell NEC were categorized into a single group, NEC. The adenocarcinoma group tended to have a larger nuclear area and longer perimeter than other histological types. The NEC group had a considerably higher Ki-67 labeling index and significantly higher CPIx than other histological types (p = .030). A significant positive correlation was observed between the Ki-67 labeling index and CPIx for all cases (r = 0.362, p = .002).

CONCLUSION

The Ki-67 labeling index and flow cytometric analyses focus on proliferative activity for the distinction of histological types of lung cancer, thereby guiding clinical decision-making.

Comparison of small biopsy and cytology specimens: Subtyping of pulmonary adenocarcinoma

Objectives

The aims of this study was to investigate the use of cytologic samples for subclassification of lung adenocarcinoma and the cytologic-histologic correlation in lung adenocarcinoma subtypes using small samples.

Methods and Methods

Cytological characteristics of lung adenocarcinoma subtypes were summarized by a literature review. Cytology samples from 115 patients with lung adenocarcinoma confirmed by small biopsies were classified by subtype. The diagnostic concordance of subtypes between biopsy and cytology samples was assessed.

Results

Among the 115 cases, 62 (53.9%) had acinar predominant pattern, 16 (13.9%) were papillary predominant pattern, 29 (25.2%) had solid predominant pattern, 3 (2.6%) had lepidic predominant pattern, and 5 (4.3%) had micropapillary predominant pattern. All corresponding cytologic samples were classified into five subtypes based on cytomorphology features, with concordance rates of 74.2% (46 patients) in c-acinar subtype, 56.3% (nine patients) in c-papillary subtype, 24.1% (seven patients) in c-solid subtype, 66.7% (two patients) in c-lepidic subtype, and 40% (two patients) in c-micropapillary subtype. Collectively, the cytology and small biopsy concordance rate was approximately 57.4%.

Conclusion

Subtyping of lung adenocarcinoma using cytologic specimens is challenging and the consistency rate varies with the subtype. Acinar predominant tumors have an excellent cytologic-histologic correlation compared to tumors with predominant solid or micropapillary pattern. Evaluating cytomorphologic features of different lung adenocarcinoma subtypes can reduce the false-negative rate of lung adenocarcinoma, particularly for the mild, atypical micropapillary subtype, and improve diagnostic accuracy.

Machine learning-based gene alteration prediction model for primary lung cancer using cytologic images

BACKGROUND

Understanding the gene alteration status of primary lung cancers is important for determining treatment strategies, but gene testing is both time-consuming and costly, limiting its application in clinical practice. Here, potential therapeutic targets were selected by predicting gene alterations in cytologic specimens before conventional gene testing.

METHODS

This was a retrospective study to develop a cytologic image-based gene alteration prediction model for primary lung cancer. Photomicroscopic images of cytology samples were collected and image patches were generated for analyses. Cancer-positive (n = 106) and cancer-negative (n = 32) samples were used to develop a neural network model for selecting cancer-positive images. Cancer-positive cases were randomly assigned to training (n = 77) and validation (n = 26) data sets. Another neural network model was developed to classify cancer images of the training data set into 4 groups: anaplastic lymphoma kinase (ALK)-fusion, epidermal growth factor receptor (EGFR), or Kirsten rat sarcoma viral oncogene homologue (KRAS) mutated groups, and other (None group), and images of the validation data set were classified. A decision algorithm to predict gene alteration for cases with 3 probability ranks was developed.

RESULTS

The accuracy and precision for selecting cancer-positive patches were 0.945 and 0.991, respectively. Predictive accuracy for the EGFR and KRAS groups in the validation data set was ~0.95, whereas that for the ALK and None groups was ~0.75 and ~ 0.80, respectively. Gene status was correctly predicted in the probability rank A cases. The model extracted characteristic conventional cytologic findings in images and a novel specific feature was discovered for the EGFR group.

CONCLUSIONS

A gene alteration prediction model for lung cancers by machine learning based on cytologic images was successfully developed.

Cytomorphometric and flow cytometric analyses using liquid-based cytology materials in subtypes of lung adenocarcinoma

BACKGROUND

The histological classifications of invasive lung adenocarcinoma subtypes are considered to predict patient prognosis after surgical treatment. The objectives of this study were to evaluate cytomorphological characteristics and proliferative activities among the histological predominant patterns by performing cytomorphometric and flow cytometric analyses using liquid-based cytology materials.

METHODS

Cytological samples fixed by liquid-based cytology preservatives from 53 surgically-resected lung adenocarcinoma specimens were obtained between August 2018 and November 2019. The Papanicolaou-stained and paired Ki-67-stained slides were analyzed for calculating nuclear morphology (nuclear area, nuclear perimeter and nuclear circularity) and Ki-67 labeling index using software. The cell proliferation index (CPIx) was calculated and cellular information including cell cycle stage of tumor cells was obtained by flow cytometry.

RESULTS

The 53 cases included papillary (n = 29), acinar (n = 8), lepidic (n = 5), and solid (n = 4) subtypes, and invasive mucinous adenocarcinoma (n = 7) were also included. In the lepidic pattern, nuclear area (79.6 ± 28.8 μm² ) and perimeter (34.1 ± 6.1 μm) were relatively larger and longer than those of the other predominant patterns. The Ki-67 labeling index of the solid pattern (27.9 ± 12.5%) was highest compared with those of other predominant patterns. There were statistically significant differences in the lepidic versus solid patterns and the papillary versus solid patterns (p = .013 and p = .039, respectively). The calculated mean CPIx of the lepidic and the acinar patterns were approximately two-fold higher than those of the other predominant patterns.

CONCLUSION

By revealing the differences of cytomorphological characteristics, these methodologies might be used for diagnosing cytopathological materials using digital cytopathology.

Pulmonary carcinomas arising in association with scar: Cytomorphologic features in histologically confirmed cases

BACKGROUND

Lung carcinoma arising in association with scar tissue is a well-reported but much debated phenomenon. Scar tissue complicates imaging and pathologic tumor measurement for cancer staging. To the best of our knowledge, the cytological findings in lung scar carcinoma (LSC) have not been described in the literature. Therefore, the aim of this study was to characterize the findings in fine-needle aspirations (FNA) from histologically confirmed LSCs.

METHODS

LSCs were identified on retrospective search. Cases with preoperative FNA material were reviewed, including non-scar cases that were used for comparison. The clinical and histopathology findings were recorded.

RESULTS

Twenty-seven cases associated with scar tissue had material for review and 35 cases not associated with scar tissue were used for comparison. The proportion of fibrosis in resection specimens ranged from 10% to 80%. Five (19%) FNA cases were hypocellular. There was no statistically significant difference between the scar and non-scar groups in terms of overall cellularity and diagnostic categories (P = .113 and P = .17, respectively). There was correlation between cytology and dominant pattern on histology in 19 (79%) adenocarcinoma cases. Spindle cells and fibrous or fibroelastotic fragments were present in 22 (81%) cases.

CONCLUSION

This is the first study describing the cytology associated with LSCs. The presence of fibrosis did not adversely impact cellularity, which is likely due to multiple excursions and selective microdissection of tumor cells by the FNA needle. The cytomorphological and histological patterns correlated in most cases. FNA is able to provide a preoperative diagnosis of carcinoma despite the presence of fibrosis.

Appreciation of Pattern in Diagnosis of Lung Adenocarcinoma from Cytology Specimen: Our Experience with Fine Needle Aspiration Cytology and Cell Block in a Resource Constraint Setup

BACKGROUND AND AIMS

Advent of personalised treatment needs correct diagnosis of lung adenocarcinoma with its molecular subtyping. Minimal use of special stain or immunohistochemistry (IHC) in small specimens save material for molecular testing. Various histologic patterns in adenocarcinoma (ADC) subtypes have different prognostic implications and current recommendation is to describe these patterns in small specimens. Aim of this study was to diagnose adenocarcinoma from cytology specimens depending on adenocarcinoma pattern on fine needle aspiration smears and cell blocks. We also studied the additional role of cell blocks as a platform for special stain and IHC.

MATERIALS AND METHODS

Conventional smears and cell block (CB) preparation were examined from transthoracic CT guided FNA samples of suspicious lung malignancy cases. Clear defining architectural pattern and cytomorphological features in favour of adenocarcinoma were evaluated and mucin stain and IHC were used as and when required.

RESULTS

A total of 86 cases were included in this study, of which 83 cases were diagnosed as adenocarcinoma, 52 (62.5%) showed clear cut evidence of adenocarcinoma from smears and CBs. CB morphology alone aided the diagnosis in 12. Various ADC patterns in combination or alone were appreciated in these 64 cases. Sixteen needed mucin stain and 3 needed IHC for diagnosis. Forty one were ADC with solid pattern of which 39 showed high nuclear grade.

CONCLUSION

Adequately cellular FNA smears and corresponding cell blocks of optimal quality can aid effectively in diagnosing adenocarcinoma and appreciating its pattern. Therefore, it would minimize the need for special stain and/or IHC with preservation of more material for molecular testing.

Morphological characterization and molecular profiling of malignant pericardial effusion in patients with pulmonary adenocarcinoma

Context

Malignant pericardial effusions (MPCEs) is a common complication observed in advanced pulmonary adenocarcinoma. In such cases, investigating molecular alterations can have significant therapeutic implication in determining anticancer drugs.

Aim

The objective was to evaluate the significance of cell block technique in the diagnosis of MPCE and further investigate the morphological and molecular profiles of MPCE in patients with pulmonary adenocarcinoma.

Setting and Design

Cytopathological and molecular profiles of 19 MPCE cases in patients with pulmonary adenocarcinoma were retrospectively analyzed. The control group consisted of 14 malignant pleural effusion (MPE) cases in patients with pulmonary adenocarcinoma.

Materials and Methods

Anaplastic lymphoma kinase (ALK) and tyrosine-protein kinase Met (C-MET) expression was evaluated by fluorescence in situ hybridization (FISH). Epithelial growth factor receptor (EGFR) and K-Ras (KRAS) mutations were detected by ARMS real-time polymerase chain reaction (RT-PCR).

Statistical Analysis Used

Associations between MPCE and MPE were analyzed using Fisher's exact test.

Results

MPCE was found to have micropapillary and solid pattern predominant with mucin secretion compared to acinar patterns, as seen in MPE. Seventeen MPCE cases (89.5%) and all MPE cases (100%) underwent molecular analysis. Mutations in EGFR and KRAS, ALK rearrangement, and C-MET amplification were observed in MPCE and MPE with statistical differences. Additionally, two MPCE cases demonstrated EGFR T790M mutation and multiple insertions at L858.

Conclusions

MPCE shows micropapillary and solid cytological patterns predominant with mucin secretion. MPCE are suitable to analyze oncogenic mutations and to develop targeted therapy for patients with pulmonary adenocarcinoma. Further molecular investigations may reveal novel molecular alterations.

Cardiac tamponade as an initial presentation of papillary carcinoma with psammoma bodies and intranuclear grooves-A diagnostic dilemma

Involvement of body fluids by adenocarcinoma is a common phenomenon. However, metastasis to the pericardial fluid by adenocarcinoma is a rare occurrence. The most common malignancies associated with malignant pericardial effusion are carcinoma of the lung, breast, esophagus, melanoma, lymphoma, and leukemia. Here, we discuss a case of a 36-year-old female with hemorrhagic pericardial effusion presenting with cardiac tamponade and psammoma bodies which was suspected and reported as metastatic papillary carcinoma of thyroid on cytomorphology; however, the immunocytochemical and radiological features confirmed metastatic papillary adenocarcinoma of lung contrary to the thyroid which is more common and expected.

Nonsmall cell lung cancer with rare exon 7 p.A289V mutation in the EGFR gene responds to Icotinib treatment: A case report

RATIONALE

Mutation p.A289V involving extracellular region of epidermal growth factor receptor (EGFR) exon 7 has not yet been reported in nonsmall cell lung cancer (NSCLC). Studies have shown p.A289V mutation responding to tyrosine kinase inhibitors (TKIs) in glioblastoma cell lines suggesting the point mutation as a potential therapeutic target. However, sufficient evidence of the effect of TKI treatment on the p.A289V mutation involved in NSCLC is not available.

PATIENT CONCERNS

An 80-year-old nonsmoker male with lung mass was suffering from severe bone pain.

DIAGNOSIS

Needle biopsy and positron emitted tomography/computed tomography were performed. The patient was diagnosed with advanced NSCLC adenocarcinoma with bone and lymphatic metastasis. Next-generation sequencing of circulating tumor DNA was performed, which identified a p.A289V mutation in the EGFR gene of the patient.

INTERVENTIONS

Our patient refused to receive chemotherapy and tried Icotinib treatment.

OUTCOMES

Our patient had a partial response to Icotinib after treatment for 5 months during the therapeutic trial by TKIs. The patient showed adverse symptoms of mild diarrhea and rash (Common Terminology Criteria for Adverse Events grade 1) during the treatment.

LESSONS

In this case, Icotinib prevented completion of the signal transduction cascade of p.A289V mutant in NSCLC. Our finding may expand the EGFR mutation spectrum for TKI treatment in NSCLC. However, the finding needs to be confirmed at a larger scale with NSCLC in Chinese and other populations.

Molecular genetic alterations in thyroid transcription factor 1-negative lung adenocarcinoma in cytology specimens: A subset with aggressive behavior and a poor prognosis

BACKGROUND

Patients with thyroid transcription factor 1 (TTF1)-negative pulmonary adenocarcinoma (ADC) have been reported to have a worse prognosis and to lack epidermal growth factor receptor (EGFR) mutations. This study describes a series of cytology specimens from patients with clinically confirmed pulmonary carcinoma negative for TTF1.

METHODS

A search for TTF1-negative ADC from 2010 to 2017 was performed. Each patient's clinical history, pathology specimens, and molecular results were noted. Two hundred ten patients with TTF1-positive pulmonary ADC formed the control group.

RESULTS

Fifty specimens were identified from 50 patients (26 females and 24 males). The median age was 58.5 years. The smoking history was as follows: 38 smokers/former smokers (76%), 10 nonsmokers (20%), and 2 patients with an unknown status (4%). Thirty-nine patients (78%) had no previous history of malignancy. The clinical stages were as follows: stage I or II (n = 2 [4%]), stage III (n = 9 [18%]), stage IV (n = 37 [74%]), and unknown (n = 2 [4%]). Patients' mean survival was 10.3 months. Molecular results were available in 43 cases. Twenty-seven cases (63%) had no mutation identified; when they were compared with the control group, TTF1-negative patients had overall shorter survival (P = .0047), even though no statistically significant difference was seen on the clinical stage. Known mutations were less frequent (P = .0095) in TTF-negative tumors (KRAS mutations, n = 11 [25%]; anaplastic lymphoma kinase [ALK], n = 3 [7%]; and EGFR, n = 2 [5%]). This was particularly true for EGFR mutations (P = .047). However, ALK rearrangements were present at an increased frequency in the TTF1-negative group (P = .018).

CONCLUSIONS

Patients with TTF1-negative lung ADC have worse overall survival, a lower frequency of known mutations, and a higher frequency of ALK alterations.

Investigation of the molecular mechanisms of hepatic injury upon naphthalene exposure in zebrafish (Danio rerio)

Naphthalene has been used worldwide as a commercial insecticide for decades, which when detected in the environment can have various negative effects on non-target organism, such as hepatotoxicity. However, the molecular mechanisms of how naphthalene acts to affect the liver in zebrafish (Danio rerio) remains unknown. In this study, we evaluated the potential toxic effects of naphthalene on livers in female adult zebrafish over a 21-day subacute exposure. Global hepatic gene expression was examined by microarrays and the results indicated the regulated genes were associated significantly with vital hepatic injury pathways and GO categories upon naphthalene exposure, such as disruptions in lipid metabolism, inflammatory response, and the carcinogenic processes. According to our observations of liver histology, nuclear enlargement as a potential indicator of cancers and hepatic lipometabolic disorder precisely were supported. The 96 h acute naphthalene tests on Tg(lysC:DsRed) and LiPan lines larvae revealed recruitment of neutrophils by the liver, as well as decreased liver size, which further confirmed hepatic inflammation response to naphthalene exposure. Thus, these findings advance the field of ecotoxicology by unveiling a new role of naphthalene as a leading cause of liver damage and provide potential biomarker-genes for environmental naphthalene monitoring.

Pulmonary Non-Small Cell Carcinoma With Morphologic Features of Adenocarcinoma or "Non-Small Cell Carcinoma Favor Adenocarcinoma" in Cytologic Specimens Share Similar Clinical and Molecular Genetic Characteristics

OBJECTIVES

Define if the presence of morphologic features of adenocarcinoma (ACA) in non-small cell lung carcinoma (NSCLC) on cytology specimens correlates with clinical and biologic features.

METHODS

A total of 209 cases of NSCLC diagnosed on fine-needle aspiration in a 3-year period were included.

RESULTS

After morphologic review, the cases were classified as ACA (n = 115), NSCLC favor ACA (n = 43), and NSCLC-not otherwise specified (NOS) (n = 18). Squamous cell (SCC) (n = 14) and NSCLC favor SCC (n = 19) were excluded from further analysis. Patients with EGFR-mutated tumors had longer overall survival than those with EGFR wild-type tumors (P = .01). When comparing cases with morphologic features of ACA, NSCLC favor ACA, and NSCLC-NOS, there were no differences in the presence or absence of tested mutations, clinical stage, or survival.

CONCLUSION

Patients diagnosed with pulmonary ACA, NSCLC favor ACA, or NSCLC-NOS in cytology specimens have similar clinical stage, survival, and molecular alterations.

A comparison of ALK gene rearrangement and ALK protein expression in primary lung carcinoma and matched metastasis

AIMS

The 2013 College of American Pathologists, the Association for Molecular Pathology and the International Association for the Study of Lung Cancer guideline for EGFR and ALK testing in lung carcinoma indicates that either the primary tumour or the metastasis is suitable for testing. The heterogeneity of gene mutations has been studied extensively, while similar reports on gene rearrangements are limited. The aim of this study was to determine if ALK status between primary tumour and matched metastasis differs.

METHODS AND RESULTS

Fifteen ALK fluorescence in-situ hybridization (FISH) rearranged and 19 non-ALK FISH rearranged adenocarcinomas were collected retrospectively based on availability of tissue from a matched metastatic site. Sixty-eight samples were tested by ALK FISH (Vysis ALK break-apart FISH kit) and ALK immunohistochemistry (IHC) (Ventana ALK D5F3 CDx assay). Overall agreement of FISH and IHC was 88%, with IHC showing 100% specificity and 71% sensitivity. Concordance between primary site and metastasis by ALK FISH was seen in 30 cases (88%), and in 32 cases (94%) by ALK IHC. Five discordant cases were found (15%). Three ALK FISH discordant cases had low percentage of ALK FISH-positive tumour cells (average 23%, range: 18-31%) and all were negative by ALK IHC. One IHC discordant case had a high percentage of ALK FISH-positive tumour cells (67%), and was ALK IHC-negative. One FISH discordant case showed ALK FISH- and ALK IHC-positive primary tumour, but ALK FISH- and ALK IHC-negative metastasis.

CONCLUSIONS

ALK FISH results show more frequent discordances between primary tumour and matched metastases than ALK IHC, due probably to technical challenges and sample quality. This observation indicates that the quality of sample and technical expertise of the laboratory should guide the decision about ALK testing in clinical practice.

Prognostic considerations of the new World Health Organization classification of lung adenocarcinoma

The 2015 World Health Organization (WHO) lung adenocarcinoma classification divides tumours into categories of indolent pre-invasive, minimally invasive and predominantly lepidic and, by examining predominant patterns of invasion, allows for further stratification into intermediate and high-grade tumours. The impact of the 2015 classification on prognosis was reviewed by a PubMed search for search terms "adenocarcinoma", "lung pathology" and "prognosis" and relevant publications reviewed. These were sorted for data on stage and survival as impacted by histological classification, and survival studies were separated into all stage versus stage 1 studies. Predictive aspects of histological classification were also examined, but molecular correlates were not. The separation of adenocarcinoma in situ and minimally invasive adenocarcinoma from invasive subtypes as distinct prognostic entities and the prognostic significance, for disease specific and overall survival for low- and high-grade categories, are discussed. The impact on stage at presentation including risk of node metastasis by histology is examined, as well as histology in relation to recurrence after surgery. Early data with regard to the value of predominant histology in the prediction of chemotherapy response will also be explored.

Recent advances in the pathology and molecular genetics of lung cancer: A practical review for cytopathologists

Lung cancer is one of the most common causes of cancer-related death worldwide. Better understanding of the molecular genetic characteristics of non-small cell lung carcinoma (NSCLC), particularly adenocarcinoma, has opened the opportunity for targeted therapies. With the different molecular abnormalities and the different responses to new targeted therapies based on the histological subtype of NSCLC, there came a need to further classify NSCLC into squamous cell carcinoma and adenocarcinoma, and to perform the appropriate molecular testing in these different subtypes to guide management decisions. Given that approximately 70% of lung cancer patients have only small biopsies or cytology specimens available, incorporating the testing of these specimens into the cytopathology laboratory has been crucial. Herein, we review current concepts and recommendations on NSCLC subtyping and molecular testing that are relevant for the cytopathology community.

Classification of different patterns of pulmonary adenocarcinomas

The epidemic increase of adenocarcinoma histology accounting for more than 50% of primary lung malignancies and the advent of effective molecular targeted-therapies against specific gene alterations characterizing this tumor type have led to the reconsideration of the pathologic classification of lung cancer. The new 2015 WHO classification provided the basis for a multidisciplinary approach emphasizing the close correlation among clinical, radiologic and molecular characteristics and histopathologic pattern of lung adenocarcinoma. The terms 'bronchioloalveolar carcinoma' and 'mixed adenocarcinoma' have been eliminated, introducing the concepts of 'adenocarcinoma in situ', 'minimally invasive adenocarcinoma' and the use of descriptive predominant patterns in invasive adenocarcinomas (lepidic, acinar, papillary, solid and micropapillary patterns). 'Invasive mucinous adenocarcinoma' is the new definition for mucinous bronchioloalveolar carcinoma, and some variants of invasive adenocarcinoma have been included, namely colloid, enteric and fetal-type adenocarcinomas. A concise update of the immunomorphologic, radiological and molecular characteristics of the different histologic patterns of lung adenocarcinoma is reported here.