Immunohistochemical and molecular characterization of clear cell carcinoma of the lung

Salivary gland-like low-grade clear cell carcinomas of the thoracic cavity: A clinical, immunohistochemical, and molecular analysis of three cases

Three cases of an unusual neoplasm with striking clear cell features resembling salivary gland origin of the thoracic cavity are presented. The patients were three men between the ages of 52 and 69 years (average: 60.5 years), who presented with non-specific symptoms, such as chest pain, cough, and dyspnea. Diagnostic imaging showed that two tumors were intrapulmonary neoplasms, one in right lower lobe and one in the left upper lobe, while the third tumor was located in the anterior mediastinum. Surgical resection was accomplished in all cases. Grossly, the tumors were described as light tan, soft and well-delineated. Necrosis and hemorrhage were not present. Histologically, the three tumors showed similar morphological features consisting of a neoplastic cellular proliferation arranged in small lobules and round glandular structures, some of which contained amorphous eosinophilic secretions. Individual tumor cells had abundant clear cytoplasm, round nuclei, and inconspicuous nucleoli. Cellular atypia was minimal and only scattered mitotic figures were present. Immunohistochemical studies showed that the tumor cells were positive for pancytokeratin and GATA-3, focally and weakly positive for DOG1 and TRPS1 while negative for numerous other epithelial and neuroendocrine markers. Molecular analysis showed negative results for EGFR, ROS1, or ALK mutation, MAML2 and EWSR1 rearrangement and ETV6::NTRK3 fusion, respectively. Clinical follow up showed that all patients were alive without tumor recurrence or metastasis. We believe that the histological features, immunohistochemical profile, and the results of the molecular analysis are supportive of a yet undescribed tumor entity, provisionally designated as salivary gland-like low-grade clear cell carcinomas.

Non-small cell lung carcinoma with clear cell features: a clinicopathologic, immunohistochemical, and molecular study of 31 cases

Non-small cell lung carcinoma with predominantly clear cell features is a rare histologic presentation of lung carcinoma. We have examined 31 cases of lung carcinomas showing extensive clear cell features. The patients were 10 women and 21 men aged 47-92 years (mean: 70 years). The tumors showed a predilection for the right upper and lower lobes and measured from 0.8 to 9.5 cm (mean: 4.2 cm). By immunohistochemistry, 9 cases were typed as adenocarcinoma, 19 cases as squamous cell carcinoma, and 3 showed a "null" phenotype with complete loss of markers for adenocarcinoma or squamous cell carcinoma. Most cases that typed as adenocarcinoma showed a solid growth pattern. A subset of the solid adenocarcinoma cases showed a distinctive "pseudosquamous" morphology. Next-generation sequencing was performed in 20 cases and showed a variety of molecular alterations. The most common abnormalities were found in the TP53 gene (9 cases), FGFR gene family (8 cases), KRAS (5 cases), AKT1 (5 cases), and BRAF (3 cases). Clinical follow-up was available in 21 patients; 16/21 patients died of their tumors from 6 months to 12 years after initial diagnosis (mean: 4.2 years, median: 1.5 years). Four patients were alive and well from 4 to 27 years (mean: 11.5 years, median: 7.5 years); all were pathologic stage 1 or 2. NSCLC with clear cell features can display aggressive behavior and needs to be distinguished from various other tumors of the lung that can show clear cell morphology. The identification of targetable molecular alterations in some of these tumors may be of value for therapeutic management.

Non-Small Cell Lung Carcinoma With Clear Cell Features and FGFR3::TACC3 Gene Rearrangement : Clinicopathologic and Next Generation Sequencing Study of 7 Cases

Seven cases of primary lung tumors characterized histologically by clear cell morphology and a distinctive FGFR3::TACC3 gene rearrangement are described. The tumors arose in 4 women and 3 men, aged 47 to 81 years (mean=68). They occurred in peripheral locations, predominantly subpleural, and ranged in size from 1.4 to 6.5 cm (mean=4.1 cm). All tumors showed a solid growth pattern with abundant central areas of necrosis and marked nuclear pleomorphism. The tumors demonstrated clear cell histology, with large cohesive tumor cells displaying atypical nuclei and abundant clear cytoplasm. Immunohistochemical stains identified a squamous phenotype in 5 cases and an adenocarcinoma phenotype in 2 cases. One case was a squamous cell carcinoma with focal glandular component, and one of the squamous cell carcinomas showed focal sarcomatoid changes. Next generation sequencing identified FGFR3::TACC3 gene rearrangements in all 7 cases. One case demonstrated a concurrent activating FGFR3 mutation and a second case demonstrated concurrent FGFR3 amplification. Two cases harbored a concurrent KRAS G12D mutation. One case harbored both KRAS and EGFR mutations, and 1 case had a concurrent TP53 mutation. Non-small cell lung carcinoma harboring FGFR3::TACC3 gene rearrangements is extremely rare, and this rearrangement may potentially be enriched in tumors that demonstrate clear cell histology. Identification of FGFR3::TACC3 in patients with lung carcinomas with clear cell features may be of importance as they could potentially be candidates for therapy with tyrosine kinase inhibitors.

Diagnosis of lung adenocarcinoma with clear cell features in pleural effusion: Cytomorphologic features, immunocytochemical studies, and differential diagnosis

Clear cell adenocarcinoma (CCA) of the lungs is no longer referred to as a subtype in recent classifications of lung adenocarcinoma. Like signet ring features, clear cell features are regarded as cytological features rather than histological subtypes. Additionally, in serous fluids, adenocarcinoma metastasis with clear cell features is a diagnostic challenging entity due to other tumors that come to mindfirst during the differential diagnosis. Here we report a case, diagnosed as CCA of lung metastasis in pleural fluid and evaluated its differential diagnosis.

Clear cell adenocarcinoma of the lung: a SEER analysis

Clear cell adenocarcinoma (CCA) in lung has been considered as a rare subtype of lung adenocarcinoma. However, recent classifications of lung adenocarcinoma proposed to discontinue CCA due to lack of available data with clinical significance. Patients with CCA and lung adenocarcinoma not otherwise specified (LANOS) were queried from The Surveillance, Epidemiology, and End Results Program (SEER) database. Cancer-specific survival was studied according to gender (male, female), age (0-69, 70+), SEER specific stage A system (localized, regional and distant), year of diagnosis (1973-2000, 2001-2013), surgery (yes, no), and radiation therapy (yes, no) using Kaplan-Meier curves. Multivariate analysis was used to study independent predictors of cancer-specific survival. A total of 1,227 and 233,154 patients with the diagnosis of CCA and LANOS respectively were found in the SEER database. CCA histology was significantly associated with an early year of diagnosis, younger age, early stage, surgery, and lack of radiation. Kaplan-Meier curves showed that patients with CCA histology had significantly better cancer-specific survival (P<0.0001, Log-Rank). Subset analysis demonstrated the difference in cancer-specific survival between CCA and NOS histology was significant in localized and regional but not distant stage disease (P=0.0453, 0.0009, 0.0664, respectively). Patients with CCA histology have superior survival in the locoregional stage according to our SEER analysis, suggesting its unique role in prognosis despite it being removed from recent pathologic classifications.

Clinical Presentation and Treatment Options for Clear Cell Lung Cancer: University of Cincinnati A Case Series and Literature Review of Clear Cell Lung Cancer

Clear cell carcinomas are common finding in renal, ovarian and uterine carcinomas. However, clear cell lung cancer (CCLC), first described by Liebow and Castleman in 1963, is considered an extremely rare variant of lung tumors. The 2011 WHO classification of lung tumors considered CCLC as a rare cytologic feature of squamous cell or adenocarcinomas. It is no longer recognized as a formal subtype, albeit it can be referred to in the pathological diagnosis as “with clear cell features” even with marginal fractions of the tumor cells. Such recognition is needed since the variation in clinical features and outcome in this subset of patients. The disease has a clinically vague natural history, is characterized by slight female predominance and is often seen in the elderly. As frequently encountered with rare diseases, its clinical course and treatment options have many questions still yet to be answered. In this paper, we review both the natural history and treatment options mentioned in literature, in the light of our experience by reporting a case series of four patients diagnosed with CCLC and highlight their aspects.

Analysis of mutational and clinicopathologic characteristics of lung adenocarcinoma with clear cell component

Introduction

Lung adenocarcinoma with clear cell component is extremely rare and the cases reported in literature remain scarce. The biological behaviors, clinicopathologic characteristics, mutational status and prognosis of lung adenocarcinoma with clear cell component are still uncertain.

Methods

Thirty-eight lung adenocarcinomas with clear cell component and 1659 lung adenocarcinomas were subjected to the study. All the corresponding clinicopathologic data, the distributions of relapse-free survival (RFS) and overall survival (OS), and the status of gene mutations were investigated.

Results

Of 1697 adenocarcinomas, 38 (2.2%) had clear cell component. Fifty percent of adenocarcinomas with clear cell component (11/22) harbored EGFR mutation, 41 percent (9/22) harbored KRAS mutation and 5 percent (1/22) harbored AKT1 mutation. Univariable analysis revealed that sex, age, tumor stage, tumor size, nodal stage and pathology were all significant predictors of RFS and OS while the tumor size and nodal stage were still significant predictors in multivariable analysis. There were significantly differences in RFS and OS for lung adenocarcinomas with clear cell component compared with those lung adenocarcinomas.

Conclusions

Lung adenocarcinoma with clear cell component is a rare, malignant tumor with poor prognosis and displays more frequent EGFR and KRAS mutations.

High-grade fetal adenocarcinoma of the lung is a tumour with a fetal phenotype that shows diverse differentiation, including high-grade neuroendocrine carcinoma: a clinicopathological, immunohistochemical and mutational study of 20 cases

AIMS

High-grade fetal adenocarcinoma (H-FLAC) is a rare variant of pulmonary adenocarcinoma; this study aims to elucidate its clinicopathological features and genetic abnormalities.

METHODS AND RESULTS

Clinicopathological, immunohistochemical and mutational analyses were performed on 20 surgically resected lung cancers that showed H-FLAC histology in various proportions. These tumours predominantly occurred in elderly males and in 10 patients who were heavy smokers. Four cases were pure H-FLAC, and 16 cases were mixed H-FLAC, which were found to be combined with conventional-type adenocarcinoma (15 cases), large-cell neuroendocrine carcinoma (three cases), small-cell carcinoma (one case), enteric adenocarcinoma (two cases), choriocarcinoma (two cases), and a solid-clear cell pattern (seven cases). The fetal phenotype and diverse differentiation were supported by the immunoexpression of α-fetoprotein (95%), thyroid transcription factor-1 (TTF-1) (50%), neuroendocrine markers (30-45%), proneural markers (50-69%), and CDX2 (40%). Except for TTF-1 expression (pure H-FLACs, 0%; mixed H-FLACs, 63%), there were no significant differences in histological or immunohistochemical findings between pure and mixed H-FLACs. EGFR, KRAS, BRAF and PIK3CA mutations were identified in 20%, 0%, 0% and 7% of the tumours, respectively.

CONCLUSIONS

Lung adenocarcinomas with H-FLAC features possess the potential for multidirectional differentiation, and are not strongly associated with known major driver gene mutations.

Large cell carcinoma of the lung: a tumor in search of an author. A clinically oriented critical reappraisal

Large cell carcinoma (LCC) is a merely descriptive term indicating a subtype of lung cancer with no specific features of small-cell lung cancer (SCLC), adenocarcinoma (ADC) or squamous cell carcinoma (SQC). This diagnosis is allowed on surgical specimens only, whereas its counterpart in biopsy/cytology samples is non-small-cell lung carcinoma (NSCLC), not otherwise specified (NOS). Although these two terms do not fulfill the same concept, they can be interchangeable synonyms at the clinical level, reflecting, in different ways, the inability to define a specific subtype. Immunohistochemistry (IHC), next generation sequencing (NGS) analysis and, historically, electron microscopy have been unveiling diverse cell differentiation lineages in LCC, resulting in LCC-favor ADC, LCC-favor SQC and LCC-favor large-cell neuroendocrine carcinoma (LCNEC), the latter hopefully to be included into the neuroendocrine tumor (NET) group in the future. Paradoxically, however, the interpretation issues of LCC/NSCLC-NOS are not diminishing, but even increasing albeight an accurate diagnosis is oncologically required and crucial. Also, rare LCC/NSCLC-NOS cases exhibiting null/unclear phenotype, are difficult to classify, and this terminology could be maintained for the sake of classification (basically these tumors are serendipitous ADC, as also confirmed by the lack of p40). In this review article, seven relevant issues to LCC have been addressed by using a question-answer methodology, with final key points discussing major interpretation issues. In conclusion, most LCC/NSCLC-NOS may be eventually re-classified and addressed by exploiting IHC and/or molecular testing to satisfy the criteria of precision medicine (the right drug, to the right patient, at the right time).

Utility of Immunohistochemistry in the Diagnosis of Pleuropulmonary and Mediastinal Cancers: A Review and Update

Context

Immunohistochemistry has become an indispensable ancillary tool for the accurate classification of pleuropulmonary and mediastinal neoplasms necessary for therapeutic decisions and predicting prognostic outcome in the era of personalized medicine. Diagnostic accuracy has significantly improved because of the continuous discoveries of tumor-associated biomarkers and the development of effective immunohistochemical panels.

Objective

To increase the accuracy of diagnosis and classify pleuropulmonary neoplasms through immunohistochemistry.

Data Sources

Literature review, authors' research data, and personal practice experience.

Conclusions

This review article has shown that appropriately selecting immunohistochemical panels enables pathologists to effectively diagnose most primary pleuropulmonary neoplasms and differentiate primary lung tumors from a variety of metastatic tumors to the lung. The discovery of new mutation-specific antibodies identifying a subset of specific gene-arranged lung tumors provides a promising alternative and cost-effective approach to molecular testing. Knowing the utilities and pitfalls of each tumor-associated biomarker is essential to avoiding potential diagnostic errors.

Advances in lung adenocarcinoma classification: a summary of the new international multidisciplinary classification system (IASLC/ATS/ERS)

Due to advances in the understanding of lung adenocarcinoma since the advent of its 2004 World Health System classification, an international multidisciplinary panel [sponsored by the International Association for the Study of Lung Cancer (IASLC), American Thoracic Society (ATS), and European Respiratory Society (ERS)] has recently updated the classification system for lung adenocarcinoma, the most common histologic type of lung cancer. Here, we summarize and highlight the new criteria and terminology, certain aspects of its clinical relevance and its potential treatment impact, and future avenues of research related to the new system.

Large cell carcinoma of lung: On the verge of extinction?

Pulmonary large cell carcinoma is a tumor whose existence as a defined entity has been challenged in recent years in the wake of advances in techniques to subtype lung cancer. Large cell carcinoma has been defined in the past as a tumor that lacks morphologic evidence of either glandular or squamous differentiation. This rather vague definition and the inclusion of more specific entities such as large cell neuroendocrine carcinoma, basaloid carcinoma, lymphoepithelioma-like carcinoma, clear cell carcinoma, and large cell carcinoma with rhabdoid phenotype as subtypes of large cell carcinoma has not only diluted the homogeneity of this entity but has also contributed to its use as a "wastebin" category for tumors lacking a definitive morphologic pattern. Today, there is increasing evidence that a large proportion of these tumors can be subtyped further using modern immunohistochemical and molecular methods. This is of special value not only from a diagnostic point of view but becomes increasingly important in terms of treatment choice since the selection of therapeutic modalities is often based on specific tumor histology. When viewed in this light, large cell carcinoma of the lung--as defined today--appears to be an outdated entity that needs to be reevaluated taking into account not only light microscopic findings but also the results of adjunct techniques such as immunohistochemistry and molecular profiling so that patients can benefit from more targeted therapies. This review examines the entity of pulmonary large cell carcinoma from these aspects and tries to delineate a practical diagnostic approach until further redefinition of this tumor is in place.