International Association for the Study of Lung Cancer Study of Reproducibility in Assessment of Pathologic Response in Resected Lung Cancers After Neoadjuvant Therapy.

INTRODUCTION: Pathologic response has been proposed as an early clinical trial end point of survival after neoadjuvant treatment in clinical trials of NSCLC. The International Association for the Study of Lung Cancer (IASLC) published recommendations for pathologic evaluation of resected lung cancers after neoadjuvant therapy. The aim of this study was to assess pathologic response interobserver reproducibility using IASLC criteria. METHODS: An international panel of 11 pulmonary pathologists reviewed hematoxylin and eosin-stained slides from the lung tumors of resected NSCLC from 84 patients who received neoadjuvant immune checkpoint inhibitors in six clinical trials. Pathologic response was assessed for percent viable tumor, necrosis, and stroma. For each slide, tumor bed area was measured microscopically, and pre-embedded formulas calculated unweighted and weighted major pathologic response (MPR) averages to reflect variable tumor bed proportion. RESULTS: Unanimous agreement among pathologists for MPR was observed in 68 patients (81%), and inter-rater agreement (IRA) was 0.84 (95% confidence interval [CI]: 0.76-0.92) and 0.86 (95% CI: 0.79-0.93) for unweighted and weighted averages, respectively. Overall, unweighted and weighted methods did not reveal significant differences in the classification of MPR. The highest concordance by both methods was observed for cases with more than 95% viable tumor (IRA = 0.98, 95% CI: 0.96-1) and 0% viable tumor (IRA = 0.94, 95% CI: 0.89-0.98). The most common reasons for discrepancies included interpretations of tumor bed, presence of prominent stromal inflammation, distinction between reactive and neoplastic pneumocytes, and assessment of invasive mucinous adenocarcinoma. CONCLUSIONS: Our study revealed excellent reliability in cases with no residual viable tumor and good reliability for MPR with the IASLC recommended less than or equal to 10% cutoff for viable tumor after neoadjuvant therapy.

Defining Morphologic Features of Invasion in Pulmonary Nonmucinous Adenocarcinoma With Lepidic Growth: A Proposal by the International Association for the Study of Lung Cancer Pathology Committee.

INTRODUCTION: Since the eight edition of the Union for International Cancer Control and American Joint Committee on Cancer TNM classification system, the primary tumor pT stage is determined on the basis of presence and size of the invasive components. The aim of this study was to identify histologic features in tumors with lepidic growth pattern which may be used to establish criteria for distinguishing invasive from noninvasive areas. METHODS: A Delphi approach was used with two rounds of blinded anonymized analysis of resected nonmucinous lung adenocarcinoma cases with presumed invasive and noninvasive components, followed by one round of reviewer de-anonymized and unblinded review of cases with known outcomes. A digital pathology platform was used for measuring total tumor size and invasive tumor size. RESULTS: The mean coefficient of variation for measuring total tumor size and tumor invasive size was 6.9% (range: 1.7%-22.3%) and 54% (range: 14.7%-155%), respectively, with substantial variations in interpretation of the size and location of invasion among pathologists. Following the presentation of the results and further discussion among members at large of the International Association for the Study of Lung Cancer Pathology Committee, extensive epithelial proliferation (EEP) in areas of collapsed lepidic growth pattern is recognized as a feature likely to be associated with invasive growth. The EEP is characterized by multilayered luminal epithelial cell growth, usually with high-grade cytologic features in several alveolar spaces. CONCLUSIONS: Collapsed alveoli and transition zones with EEP were identified by the Delphi process as morphologic features that were a source of interobserver variability. Definition criteria for collapse and EEP are proposed to improve reproducibility of invasion measurement.

Multicenter study of diffuse pleural mesothelioma. histopathological and immunohistochemical features / Estudio multicéntrico de características histopatológicas e inmunohistoquímicas del mesotelioma pleural difuso

Abstract The pathological diagnosis of diffuse pleural mesothelioma (DPM) contributes to treatment selection and clinical trials interpretation. To know its characteristics and evaluate the viability of comprehensive pathological diagnosis of DPM in Argentina we did a retrospective descriptive study of DPM cases reported from 2009 to 2018. We analyzed 398 cases corresponding to 238 (60%) men and 160 (40%) women, median age 66 years, from surgical biopsies (78%), small biopsies (16.5%) and surgical resections (5.5%). The 77% were epithelioid (E-DPM), 12% biphasic, 10% sarcomatoid, and 4 cases transitional variant. In E-DPM the main pattern was tubular in 36% and solid in 33%. There was a second pattern in 179 cases. Considering the main pattern and the second together, 48% presented tubular subtype and 48% solid subtype. Stroma, necrosis, and nuclear score showed significant differences between E-DPM and non-epithelioid mesotheliomas. Overall tumor grade was predominantly low in E-DPM, except for 42% of the solid main pattern. We recognized the transitional variant extensively in 4 cases and focally in 8. The immunohistochemical antibody panel used included pan-cytokeratin, calretinin, WT-1, cytokeratin 5, CEA and TTF-1. The expression of cytokeratin 5, calretinin and WT-1 was lower in the sarcomatoid type (43%, 87 and 37%) than in the epithelioid type (92%, 98% and 93%). This study highlights the tumor heterogeneity of DPM that shows the diagnostic difficulty, and the feasibility of evaluating histological aggressiveness in E-DPM, B-DPM and S-DPM in our country.

Resumen El diagnóstico patológico del mesotelioma pleural difuso (MPD) contribuye a la selección del tratamiento y a la interpretación de los ensayos clínicos. Para conocer sus características y evaluar la viabilidad del diagnóstico patológico de MPD en Argentina se realizó un estudio descriptivo retros pectivo de los casos de MPD informados de 2009 a 2018. Se analizaron 398 casos correspondientes a 238 (60%) hombres y 160 (40%) mujeres, mediana de edad de 66 años, a partir de biopsias quirúrgicas (78%), biopsias pequeñas (16.5%) y resecciones quirúrgicas (5.5%). El 77% fue epitelioide (E-MPD), 12% bifásicos, 10% sarcomatoides y 4 casos variante transicional. En E-MPD se encontró como patrón principal el tubular en 36% y el sólido en 33%. Hubo un segundo patrón en 179 casos. Considerando el principal y el segundo patrón en conjunto, el 48% presentó subtipo tubular y el 48% subtipo sólido. El estroma, la necrosis y el score nuclear mostraron diferencias significativas entre E-MPD y mesoteliomas no epitelioides. El grado general del tumor fue predominantemente bajo en E-MPD, a excepción del 42% del patrón principal sólido. Reconocimos la variante transicional en forma extensa en 4 casos y focalmente en 8. La expresión de citoqueratina 5, calretinina y WT-1 fue menor en el tipo sarcomatoide (43%, 87 y 37%) que en el tipo epitelioide (92%, 98% y 93%). Este estudio destaca la heterogeneidad tumoral de MPD que evidencia la dificu ltad en el diagnóstico y la viabilidad de evaluar la agresividad histológica en E-MPD, B-MPD y S-MPD en nuestro país.

Multicenter study of diffuse pleural mesothelioma. Histopathological and immunohistochemical features.

The pathological diagnosis of diffuse pleural mesothelioma (DPM) contributes to treatment selection and clinical trials interpretation. To know its characteristics and evaluate the viability of comprehensive pathological diagnosis of DPM in Argentina we did a retrospective descriptive study of DPM cases reported from 2009 to 2018. We analyzed 398 cases corresponding to 238 (60%) men and 160 (40%) women, median age 66 years, from surgical biopsies (78%), small biopsies (16.5%) and surgical resections (5.5%). The 77% were epithelioid (E-DPM), 12% biphasic, 10% sarcomatoid, and 4 cases transitional variant. In E-DPM the main pattern was tubular in 36% and solid in 33%. There was a second pattern in 179 cases. Considering the main pattern and the second together, 48% presented tubular subtype and 48% solid subtype. Stroma, necrosis, and nuclear score showed significant differences between E-DPM and non-epithelioid mesotheliomas. Overall tumor grade was predominantly low in E-DPM, except for 42% of the solid main pattern. We recognized the transitional variant extensively in 4 cases and focally in 8. The immunohistochemical antibody panel used included pan-cytokeratin, calretinin, WT-1, cytokeratin 5, CEA and TTF-1. The expression of cytokeratin 5, calretinin and WT-1 was lower in the sarcomatoid type (43%, 87 and 37%) than in the epithelioid type (92%, 98% and 93%). This study highlights the tumor heterogeneity of DPM that shows the diagnostic difficulty, and the feasibility of evaluating histological aggressiveness in E-DPM, B-DPM and S-DPM in our country.

El diagnóstico patológico del mesotelioma pleural difuso (MPD) contribuye a la selección del tratamiento y a la interpretación de los ensayos clínicos. Para conocer sus características y evaluar la viabilidad del diagnóstico patológico de MPD en Argentina se realizó un estudio descriptivo retrospectivo de los casos de MPD informados de 2009 a 2018. Se analizaron 398 casos correspondientes a 238 (60%) hombres y 160 (40%) mujeres, mediana de edad de 66 años, a partir de biopsias quirúrgicas (78%), biopsias pequeñas (16.5%) y resecciones quirúrgicas (5.5%). El 77% fue epitelioide (E-MPD), 12% bifásicos, 10% sarcomatoides y 4 casos variante transicional. En E-MPD se encontró como patrón principal el tubular en 36% y el sólido en 33%. Hubo un segundo patrón en 179 casos. Considerando el principal y el segundo patrón en conjunto, el 48% presentó subtipo tubular y el 48% subtipo sólido. El estroma, la necrosis y el score nuclear mostraron diferencias significativas entre E-MPD y mesoteliomas no epitelioides. El grado general del tumor fue predominantemente bajo en E-MPD, a excepción del 42% del patrón principal sólido. Reconocimos la variante transicional en forma extensa en 4 casos y focalmente en 8. La expresión de citoqueratina 5, calretinina y WT-1 fue menor en el tipo sarcomatoide (43%, 87 y 37%) que en el tipo epitelioide (92%, 98% y 93%). Este estudio destaca la heterogeneidad tumoral de MPD que evidencia la dificu ltad en el diagnóstico y la viabilidad de evaluar la agresividad histológica en E-MPD, B-MPD y S-MPD en nuestro país.

The International Association for the Study of Lung Cancer Global Survey on Programmed Death-Ligand 1 Testing for NSCLC.

INTRODUCTION: Programmed death-ligand 1 (PD-L1) immunohistochemistry (IHC) is required to determine the eligibility for pembrolizumab monotherapy in advanced NSCLC worldwide and for several other indications depending on the country. Four assays have been approved/ Communauté Européene-In vitro Diagnostic (CV-IVD)-marked, but PD-L1 IHC seems diversely implemented across regions and laboratories with the application of laboratory-developed tests (LDTs). METHOD: To assess the practice of PD-L1 IHC and identify issues and disparities, the International Association for the Study of Lung Cancer Pathology Committee conducted a global survey for pathologists from January to May 2019, comprising multiple questions on preanalytical, analytical, and postanalytical conditions. RESULT: A total of 344 pathologists from 64 countries participated with 41% from Europe, 24% from North America, and 18% from Asia. Besides biopsies and resections, cellblocks were used by 75% of the participants and smears by 11%. The clone 22C3 was most often used (69%) followed by SP263 (51%). They were applied as an LDT by 40% and 30% of the users, respectively, and 76% of the participants developed at least one LDT. Half of the participants reported a turnaround time of less than or equal to 2 days, whereas 13% reported that of greater than or equal to 5 days. In addition, quality assurance (QA), formal training for scoring, and standardized reporting were not implemented by 18%, 16%, and 14% of the participants, respectively. CONCLUSIONS: Heterogeneity in PD-L1 testing is marked across regions and laboratories in terms of antibody clones, IHC assays, samples, turnaround times, and QA measures. The lack of QA, formal training, and standardized reporting stated by a considerable minority identifies a need for additional QA measures and training opportunities.

Ciliated muconodular papillary tumor and thymoma: unusual presentation for two types of rare tumors: a case report.

We present the case of 68-year-old woman with presumptive diagnosis of lung malignancy and lymph node mediastinal disease surgically treated that resulted in two independent lesions: a ciliated muconodular papillary tumor (CMPT) and a B2 thymoma. The nodule was in right lower lobe (RLL) had irregular borders and fluorodeoxyglucose-positron emission tomography (FDG-PET) scan confirmed a 20 mm mass irradiating towards the visceral pleura and small central cavitation and moderate uptake [standardized uptake value (SUV) =2.7]. In the anterior mediastinum there was a solid 25 mm nodule with an SUV of 2.4, interpreted as a pre-vascular lymph node enlargement. Lobectomy by video-thoracoscopy has been made and anterior mediastinum mass closely related to the thymus was resected. Pulmonary tumor diagnosis was CMPT and thymoma B2 diagnosis was did in mediastinal nodule. CMPT are extremely rare lesions made up of a bronchiolar-like epithelial proliferation, with basal and mucinous cells, that usually presents as a solid or subsolid peripheral pulmonary nodule. Thymomas represent the most frequent tumor of anterior mediastinum constituted by epithelial thymic cells proliferation. There is no association described in the literature between the two histological entities. Our aim is to alert about this CMPT lung tumor and its unusual coexistence with a mediastinal mass which simulates N2 metastatic lung cancer. We considered that establish specific treatment guidelines are needed for these diseases with different prognoses.

The Promises and Challenges of Tumor Mutation Burden as an Immunotherapy Biomarker: A Perspective from the International Association for the Study of Lung Cancer Pathology Committee.

Immune checkpoint inhibitor (ICI) therapies have revolutionized the management of patients with NSCLC and have led to unprecedented improvements in response rates and survival in a subset of patients with this fatal disease. However, the available therapies work only for a minority of patients, are associated with substantial societal cost, and may lead to considerable immune-related adverse events. Therefore, patient selection must be optimized through the use of relevant biomarkers. Programmed death-ligand 1 protein expression by immunohistochemistry is widely used today for the selection of programmed cell death protein 1 inhibitor therapy in patients with NSCLC; however, this approach lacks robust sensitivity and specificity for predicting response. Tumor mutation burden (TMB), or the number of somatic mutations derived from next-generation sequencing techniques, has been widely explored as an alternative or complementary biomarker for response to ICIs. In theory, a higher TMB increases the probability of tumor neoantigen production and therefore, the likelihood of immune recognition and tumor cell killing. Although TMB alone is a simplistic surrogate of this complex interplay, it is a quantitative variable that can be relatively readily measured using currently available sequencing techniques. A large number of clinical trials and retrospective analyses, employing both tumor and blood-based sequencing tools, have evaluated the performance of TMB as a predictive biomarker, and in many cases reveal a correlation between high TMB and ICI response rates and progression-free survival. Many challenges remain before the implementation of TMB as a biomarker in clinical practice. These include the following: (1) identification of therapies whose response is best informed by TMB status; (2) robust definition of a predictive TMB cut point; (3) acceptable sequencing panel size and design; and (4) the need for robust technical and informatic rigor to generate precise and accurate TMB measurements across different laboratories. Finally, effective prediction of response to ICI therapy will likely require integration of TMB with a host of other potential biomarkers, including tumor genomic driver alterations, tumor-immune milieu, and other features of the host immune system. This perspective piece will review the current clinical evidence for TMB as a biomarker and address the technical sequencing considerations and ongoing challenges in the use of TMB in routine practice.

A Grading System for Invasive Pulmonary Adenocarcinoma: A Proposal From the International Association for the Study of Lung Cancer Pathology Committee.

INTRODUCTION: A grading system for pulmonary adenocarcinoma has not been established. The International Association for the Study of Lung Cancer pathology panel evaluated a set of histologic criteria associated with prognosis aimed at establishing a grading system for invasive pulmonary adenocarcinoma. METHODS: A multi-institutional study involving multiple cohorts of invasive pulmonary adenocarcinomas was conducted. A cohort of 284 stage I pulmonary adenocarcinomas was used as a training set to identify histologic features associated with patient outcomes (recurrence-free survival [RFS] and overall survival [OS]). Receiver operating characteristic curve analysis was used to select the best model, which was validated (n = 212) and tested (n = 300, including stage I-III) in independent cohorts. Reproducibility of the model was assessed using kappa statistics. RESULTS: The best model (area under the receiver operating characteristic curve [AUC] = 0.749 for RFS and 0.787 for OS) was composed of a combination of predominant plus high-grade histologic pattern with a cutoff of 20% for the latter. The model consists of the following: grade 1, lepidic predominant tumor; grade 2, acinar or papillary predominant tumor, both with no or less than 20% of high-grade patterns; and grade 3, any tumor with 20% or more of high-grade patterns (solid, micropapillary, or complex gland). Similar results were seen in the validation (AUC = 0.732 for RFS and 0.787 for OS) and test cohorts (AUC = 0.690 for RFS and 0.743 for OS), confirming the predictive value of the model. Interobserver reproducibility revealed good agreement (k = 0.617). CONCLUSIONS: A grading system based on the predominant and high-grade patterns is practical and prognostic for invasive pulmonary adenocarcinoma.

IASLC Multidisciplinary Recommendations for Pathologic Assessment of Lung Cancer Resection Specimens After Neoadjuvant Therapy.

Currently, there is no established guidance on how to process and evaluate resected lung cancer specimens after neoadjuvant therapy in the setting of clinical trials and clinical practice. There is also a lack of precise definitions on the degree of pathologic response, including major pathologic response or complete pathologic response. For other cancers such as osteosarcoma and colorectal, breast, and esophageal carcinomas, there have been multiple studies investigating pathologic assessment of the effects of neoadjuvant therapy, including some detailed recommendations on how to handle these specimens. A comprehensive mapping approach to gross and histologic processing of osteosarcomas after induction therapy has been used for over 40 years. The purpose of this article is to outline detailed recommendations on how to process lung cancer resection specimens and to define pathologic response, including major pathologic response or complete pathologic response after neoadjuvant therapy. A standardized approach is recommended to assess the percentages of (1) viable tumor, (2) necrosis, and (3) stroma (including inflammation and fibrosis) with a total adding up to 100%. This is recommended for all systemic therapies, including chemotherapy, chemoradiation, molecular-targeted therapy, immunotherapy, or any future novel therapies yet to be discovered, whether administered alone or in combination. Specific issues may differ for certain therapies such as immunotherapy, but the grossing process should be similar, and the histologic evaluation should contain these basic elements. Standard pathologic response assessment should allow for comparisons between different therapies and correlations with disease-free survival and overall survival in ongoing and future trials. The International Association for the Study of Lung Cancer has an effort to collect such data from existing and future clinical trials. These recommendations are intended as guidance for clinical trials, although it is hoped they can be viewed as suggestion for good clinical practice outside of clinical trials, to improve consistency of pathologic assessment of treatment response.

PD-L1 Testing for Lung Cancer in 2019: Perspective From the IASLC Pathology Committee.

The recent development of immune checkpoint inhibitors (ICIs) has led to promising advances in the treatment of patients with NSCLC and SCLC with advanced or metastatic disease. Most ICIs target programmed cell death protein 1 (PD-1) or programmed death ligand 1 (PD-L1) axis with the aim of restoring antitumor immunity. Multiple clinical trials for ICIs have evaluated a predictive value of PD-L1 protein expression in tumor cells and tumor-infiltrating immune cells (ICs) by immunohistochemistry (IHC), for which different assays with specific IHC platforms were applied. Of those, some PD-L1 IHC assays have been validated for the prescription of the corresponding agent for first- or second-line treatment. However, not all laboratories are equipped with the dedicated platforms, and many laboratories have set up in-house or laboratory-developed tests that are more affordable than the generally expensive clinical trial-validated assays. Although PD-L1 IHC test is now deployed in most pathology laboratories, its appropriate implementation and interpretation are critical as a predictive biomarker and can be challenging owing to the multiple antibody clones and platforms or assays available and given the typically small size of samples provided. Because many articles have been published since the issue of the IASLC Atlas of PD-L1 Immunohistochemistry Testing in Lung Cancer, this review by the IASLC Pathology Committee provides updates on the indications of ICIs for lung cancer in 2019 and discusses important considerations on preanalytical, analytical, and postanalytical aspects of PD-L1 IHC testing, including specimen type, validation of assays, external quality assurance, and training.

Best Practices Recommendations for Diagnostic Immunohistochemistry in Lung Cancer.

Since the 2015 WHO classification was introduced into clinical practice, immunohistochemistry (IHC) has figured prominently in lung cancer diagnosis. In addition to distinction of small cell versus non-small cell carcinoma, patients' treatment of choice is directly linked to histologic subtypes of non-small cell carcinoma, which pertains to IHC results, particularly for poorly differentiated tumors. The use of IHC has improved diagnostic accuracy in the classification of lung carcinoma, but the interpretation of IHC results remains challenging in some instances. Also, pathologists must be aware of many interpretation pitfalls, and the use of IHC should be efficient to spare the tissue for molecular testing. The International Association for the Study of Lung Cancer Pathology Committee received questions on practical application and interpretation of IHC in lung cancer diagnosis. After discussions in several International Association for the Study of Lung Cancer Pathology Committee meetings, the issues and caveats were summarized in terms of 11 key questions covering common and important diagnostic situations in a daily clinical practice with some relevant challenging queries. The questions cover topics such as the best IHC markers for distinguishing NSCLC subtypes, differences in thyroid transcription factor 1 clones, and the utility of IHC in diagnosing uncommon subtypes of lung cancer and distinguishing primary from metastatic tumors. This article provides answers and explanations for the key questions about the use of IHC in diagnosis of lung carcinoma, representing viewpoints of experts in thoracic pathology that should assist the community in the appropriate use of IHC in diagnostic pathology.

PD-L1 Immunohistochemistry Comparability Study in Real-Life Clinical Samples: Results of Blueprint Phase 2 Project.

OBJECTIVES: The Blueprint (BP) Programmed Death Ligand 1 (PD-L1) Immunohistochemistry Comparability Project is a pivotal academic/professional society and industrial collaboration to assess the feasibility of harmonizing the clinical use of five independently developed commercial PD-L1 immunohistochemistry assays. The goal of BP phase 2 (BP2) was to validate the results obtained in BP phase 1 by using real-world clinical lung cancer samples. METHODS: BP2 were conducted using 81 lung cancer specimens of various histological and sample types, stained with all five trial-validated PD-L1 assays (22C3, 28-8, SP142, SP263, and 73-10); the slides were evaluated by an international panel of pathologists. BP2 also assessed the reliability of PD-L1 scoring by using digital images, and samples prepared for cytological examination. PD-L1 expression was assessed for percentage (tumor proportional score) of tumor cell (TC) and immune cell areas showing PD-L1 staining, with TCs scored continuously or categorically with the cutoffs used in checkpoint inhibitor trials. RESULTS: The BP2 results showed highly comparable staining by the 22C3, 28-8 and SP263 assays; less sensitivity with the SP142 assay; and higher sensitivity with the 73-10 assay to detect PD-L1 expression on TCs. Glass slide and digital image scorings were highly concordant (Pearson correlation >0.96). There was very strong reliability among pathologists in TC PD-L1 scoring with all assays (overall intraclass correlation coefficient [ICC] = 0.86-0.93), poor reliability in IC PD-L1 scoring (overall ICC = 0.18-0.19), and good agreement in assessing PD-L1 status on cytological cell block materials (ICC = 0.78-0.85). CONCLUSION: BP2 consolidates the analytical evidence for interchangeability of the 22C3, 28-8, and SP263 assays and lower sensitivity of the SP142 assay for determining tumor proportion score on TCs and demonstrates greater sensitivity of the 73-10 assay compared with that of the other assays.

Interobserver Variation among Pathologists and Refinement of Criteria in Distinguishing Separate Primary Tumors from Intrapulmonary Metastases in Lung.

Multiple tumor nodules are seen with increasing frequency in clinical practice. On the basis of the 2015 WHO classification of lung tumors, we assessed the reproducibility of the comprehensive histologic assessment to distinguish second primary lung cancers (SPLCs) from intrapulmonary metastases (IPMs), looking for the most distinctive histologic features. An international panel of lung pathologists reviewed a scanned sequential cohort of 126 tumors from 48 patients and recorded an agreed set of histologic features, including tumor typing and predominant pattern of adenocarcinoma, thereby opining whether the case was SPLC, IPM, or a combination thereof. Cohen κ statistics of 0.60 on overall assessment of SPLC or IPM indicated a good agreement. Likewise, there was good agreement (κ score 0.64, p < 0.0001) between WHO histologic pattern in individual cases and SPLC or IPM status, but the proportions diversified for histologic pattern and SPLC or IPM status (McNemar test, p < 0.0001). The strongest associations for distinguishing between SPLC and IPM were observed for nuclear pleomorphism, cell size, acinus formation, nucleolar size, mitotic rate, nuclear inclusions, intraalveolar clusters, and necrosis. Conversely, the associations for lymphocytosis, mucin content, lepidic growth, vascular invasion, macrophage response, clear cell change, acute inflammation keratinization, and emperipolesis did not reach significance with tumor extent. Comprehensive histologic assessment is recommended for distinguishing SPLC from IPM with good reproducibility among lung pathologists. In addition to main histologic type and predominant patterns of histologic subtypes, nuclear pleomorphism, cell size, acinus formation, nucleolar size, and mitotic rate strongly correlate with pathologic staging status.

The Use of Immunohistochemistry Improves the Diagnosis of Small Cell Lung Cancer and Its Differential Diagnosis. An International Reproducibility Study in a Demanding Set of Cases.

INTRODUCTION: The current WHO classification of lung cancer states that a diagnosis of SCLC can be reliably made on routine histological and cytological grounds but immunohistochemistry (IHC) may be required, particularly (1) in cases in which histologic features are equivocal and (2) in cases in which the pathologist wants to increase confidence in diagnosis. However, reproducibility studies based on hematoxylin and eosin-stained slides alone for SCLC versus large cell neuroendocrine carcinoma (LCNEC) have shown pairwise κ scores ranging from 0.35 to 0.81. This study examines whether judicious use of IHC improves diagnostic reproducibility for SCLC. METHODS: Nineteen lung pathologists studied interactive digital images of 79 tumors, predominantly neuroendocrine lung tumors. Images of resection and biopsy specimens were used to make diagnoses solely on the basis of morphologic features (level 1), morphologic features along with requested IHC staining results (level 2), and all available IHC staining results (level 3). RESULTS: For the 19 pathologists reading all 79 cases, the rate of agreement for level 1 was 64.7%, and it increased to 73.2% and 77.5% in levels 2 and 3, respectively. With IHC, κ scores for four tumor categories (SCLC, LCNEC, carcinoid tumors, and other) increased in resection samples from 0.43 to 0.60 and in biopsy specimens from 0.43 to 0.64. CONCLUSIONS: Diagnosis using hematoxylin and eosin staining alone showeds moderate agreement among pathologists in tumors with neuroendocrine morphology, but agreement improved to good in most cases with the judicious use of IHC, especially in the diagnosis of SCLC. An approach for IHC in the differential diagnosis of SCLC is provided.

Tumores carcinoides pulmonares tratados quirúrgicamente valor pronóstico de la 7ª estadificación TNM

Con el objetivo de evaluar el valor pronóstico de la 7a estadificación TNM se analizaron 43 mujeres (61%) y 28 hombres (39%) con diagnóstico de tumor carcinoide tratados quirúrgicamente desde enero/1975 hasta diciembre/2011. Mediana de edad: 38 años (13-67). Presentaron carcinoide típico (CT) 63 (89%) pacientes y 8 (11%) carcinoide atípico (CA). Mediana de seguimiento: 4 años (1 - 24 años). Los estadios correspondientes a CT fueron: IA = 33 (52%), IB = 10 (16%), IIA = 2 (3%), IIB = 2 (3%), IIIA = 12 (19%) y IIIB = 2 (3%); para los CA fueron: IA = 1 (12.5%), IIB = 1 (12.5%), IIIA = 2 (25%) y IIIB = 4 (50%). No hubo diferencia estadísticamente significativa en la supervivencia global a cinco años en el análisis estratificando por estadios (p = 0.689), ni analizando separadamente cada tipo histológico (CT p = 0.547; CA p = 0.592). El intervalo libre de enfermedad fue significativamente menor (CT: 3 años vs CA: 2 años, p = 0.000) y las recaídas más frecuentes en el grupo de carcinoides atípicos (CA: 50% vs CT: 2%, p = 0.000). Los pacientes con CT presentaron buena evolución aun en estadios avanzados, mientras que los que tuvieron CA presentaron menor tiempo de supervivencia e intervalo libre de enfermedad, y mayor frecuencia de recurrencia. El subtipo histológico resultó un factor significativo de pronóstico, mientras que la 7ª estadificación TNM no contribuyó en predecir la supervivencia en los tumores carcinoides.

We analyzed 43 women (61%) and 28 men (39%) surgically treated for carcinoid tumors from Jan/1975 to Dec/2011. Median age: 38 years (13-67). Typical carcinoid (TC) appeared in 63 (89%) patients, 8 (11%) suffered from atypical carcinoid (AC). Median follow-up: 4 years (1-24). TC stages were: IA = 33 (52%), IB = 10 (16%), IIA = 2 (3%), IIB = 2 (3%), IIIA = 12 (19%) and IIIB = 2 (3%); AC stages were: IA = 1 (12.5%), IIB = 1 (12.5%), IIIA = 2 (25%) and IIIB = 4 (50%). TNM classification did not show significant differences on 5-years survival period by stage (p = 0.689), even according to histological type (TC: p = 0.547; AC: p = 0.592). The disease-free survival rate was significantly lower (TC: 3 years vs. AC: 2 years, p = 0.000) and relapses were more frequent in AC (AC: 50% vs. TC: 2%, p = 0.000). The 7th TNM staging was not influential in estimating survival from carcinoid tumours in our population. The histological subtype was a better prognostic factor.

Observational study of patients with gastroenteropancreatic and bronchial neuroendocrine tumors in Argentina: Results from the large database of a multidisciplinary group clinical multicenter study.

Neuroendocrine tumors (NET) include a spectrum of malignancies arising from neuroendocrine cells throughout the body. The objective of this clinical investigation of retrospectively and prospectively collected data was to describe the prevalence, demographic data, clinical symptoms and methods of diagnosis of NET and the treatment and long-term follow-up of patients with NET. Data were provided by the participating centers and assessed for consistency by internal reviewers. All the cases were centrally evaluated (when necessary) by the pathologists in our group. The tissue samples were reviewed by hematoxylin and eosin and immunohistochemical staining techniques to confirm the diagnosis of NET. In total, 532 cases were documented: 461 gastroenteropancreatic-NET (GEP-NET) and 71 bronchial NET (BNET). All the tumors were immunohistochemically defined according to the World Health Organization (WHO) and European Neuroendocrine Tumor Society criteria. The most common initial symptoms in GEP-NET were abdominal pain, diarrhea, bowel obstruction, flushing, gastrointestinal bleeding and weight loss. The most common tumor types were carcinoid (58.0%), non-functional pancreatic tumor (23.0%), metastatic NET of unknown primary (16.0%) and functional pancreatic tumor (3.0%). Of the BNET, 89.0% were typical and 11.0% atypical carcinoids. Of the patients with GEP-NET, 59.2% had distant metastasis at diagnosis. The locations of the primary tumors in GEP-NET were the small bowel (26.9%), pancreas (25.2%), colon-rectum (12.4%), appendix (7.6%), stomach (6.9%), esophagus (2.8%), duodenum (2.0%) and unknown primary (16.3%). The histological subtypes based on the WHO classification were well-differentiated NET (20.1%), well-differentiated neuroendocrine carcinomas (66.5%) and poorly differentiated neuroendocrine carcinomas (10.3%). Overall, 67.3% of the patients underwent surgery, 41.2% with curative intent and 26.1% for palliative purposes. The 5-year survival rates were 65.1% (95% confidence interval, 58.0-71.4%) in GEP-NET and 100.0% in typical carcinoid of the lung. This observational, non-interventional, longitudinal study aimed to accumulate relevant information regarding the epidemiology, clinical presentation and current practices in the treatment of NET patients in Argentina, providing insight into regional differences and patterns of care in this heterogeneous disease.

[Surgically treated bronchopulmonary carcinoid tumours. Prognostic value of TNM staging 7a edition]. / Tumores carcinoides pulmonares tratados quirúrgicamente. Valor pronóstico de la 7a estadificación TNM.

We analyzed 43 women (61%) and 28 men (39%) surgically treated for carcinoid tumors from Jan/1975 to Dec/2011. Median age: 38 years (13-67). Typical carcinoid (TC) appeared in 63 (89%) patients, 8 (11%) suffered from atypical carcinoid (AC). Median follow-up: 4 years (1-24). TC stages were: IA = 33 (52%), IB = 10 (16%), IIA = 2 (3%), IIB = 2 (3%), IIIA = 12 (19%) and IIIB = 2 (3%); AC stages were: IA = 1 (12.5%), IIB = 1 (12.5%), IIIA = 2 (25%) and IIIB = 4 (50%). TNM classification did not show significant differences on 5-years survival period by stage (p = 0.689), even according to histological type (TC: p = 0.547; AC: p = 0.592). The disease-free survival rate was significantly lower (TC: 3 years vs. AC: 2 years, p = 0.000) and relapses were more frequent in AC (AC: 50% vs. TC: 2%, p = 0.000). The 7th TNM staging was not influential in estimating survival from carcinoid tumours in our population. The histological subtype was a better prognostic factor.

Tumores primitivos traqueales / Tracheal primary Tumours

Antecedentes: Los tumores primitivos de la tráquea son infrecuentes y el éxito del tratamiento quirúrgico depende de la precisa indicación y selección de pacientes. Objetivos: Evaluar los factores histopatológicos y quirúrgicos que pudieran influir en la supervivencia de una serie de pacientes con tumores primarios de tráquea tratados quirúrgicamente. Material y métodos: Se estudiaron todos los pacientes con diagnóstico de tumor primitivo traqueal desde enero del 1971 hasta junio del 2011. Dieciséis de estos pacientes fueron motivo de una publicación previa. Las variables analizadas fueron: edad, tipo histológico, longitud de la resección y presencia de enfermedad en márgenes de resección. Para el análisis de supervivencia se utilizó el log rank test y las curvas de Kaplan Meier utilizando el paquete estadístico STATA 9.0. Los datos están expresados en medianas, rangos, IC 95% y porcentajes. El número de casos por grupo invalida realizar análisis multivariado. Resultados: Fueron estudiados 54 pacientes: 22 hombres (41%) y 32 mujeres (59%). Mediana de edad: 50 años. El tipo histológico más frecuente fue el carcinoma adenoide quístico (41%), seguido por el carcinoma epidermoide (19%), los tumores carcinoides (7.4%), adenocarcinomas (7.4%), el carcinoma mucoepidermoide de bajo grado (6%) y el fibrosarcoma (6%); el resto (13.2%) correspondió a lesiones benignas. La mediana de seguimiento para todos ellos fue de 2 años (rango 1-26 años). Al analizar separadamente los tumores adenoquísticos (22) y epidermoides (10), encontramos que la edad mayor a 50 años (HR 3.27, IC 95% 1.24-8.67, p = 0.017), el diagnóstico de carcinoma epidermoide (HR 12.29, IC 95% 3.18-47.49, p = 0.00), la presencia de márgenes de resección positivos (HR 5.78, IC 95% 1.42-23.64, p = 0.015) y las resecciones mayores a 6 cm (HR 11.86, IC 95% 3.31-42.44 p = 0.00) fueron factores asociados significativamente a menor tiempo de supervivencia. Conclusiones: En esta serie de tumores traqueales observamos que los pacientes mayores a 50 años, el carcinoma epidermoide, las resecciones extensas y los márgenes insuficientes fueron factores de mal pronóstico. Estos factores deben tenerse en consideración al establecer la estrategia terapéutica en cada paciente.

Background: Primary tracheal tumors are infrequent and their successful treatment depends on the selection of patients and precise surgical indications. The aim of this paper was to evaluate the histopathology and surgical factors that may influence survival in a series of patients with tracheal tumors that underwent surgery, endoscopic resection, prosthesis, and oncologic treatment. Methods: We revised the records of 54 patients with the diagnosis of tracheal tumors from January 1971 through June 2011. A report on sixteen of these patients was published previously. The following features were taken into account: age, histological type of the tumor, extent of resection of the involved trachea and the presence of remaining disease in the margins. The log Rank test and Kaplan Meier curves were used for survival analysis. Data were expressed as median, ranges, CI 95% and percentages. Multivariate analysis was not performed due to the small number of cases per group. Results: The series consisted of 54 patients, 22 men (41%) and 32 women (59%) . The median age was 50 years. The commonest histological type was adenocystic carcinoma (41%) followed by squamous cell carcinoma (19 %,) carcinoid tumors (7.4%) adenocarcinoma (7.4%), mucoepidermoid carcinoma (6%) and fibrosarcoma (6%). The remaining tumors were benign lesions (13.2%). The median follow up was 2 years, (range 1-26 years). Analyzing separately adenocystic carcinomas (22) and squamous cell carcinomas (10), we found that age older than 50 years (HR 3.27, 95% CI 1.24-8.67, p = 0.017), diagnosis of squamous cell carcinoma (HR 12.29, 95 % 3.18-47.49, p = 0.00), the presence of tumor in the margins (HR 5.78, 95% CI 1.42-23.64, p = 0.015), and resections greater than 6 cm (HR 11.86, 95% CI 3.31-42.44 p = 0.00) were significantly associated with shorter survival time. Conclusion: This larger series of cases confirm, and extend the conclusions of our previous report. We found that in both, adenocystic carcinoma (ACC) and squamous cell carcinoma (SCC), the age, the presence of tumor in the resection margins, and the extent of resection (more than 6 cm) were significantly associated with a poorer prognosis and shorter survival time.