Optimizing molecular testing of lung cancer needle biopsy specimens: potential solutions from an interdisciplinary qualitative study.

BACKGROUND: Molecular testing can detect actionable genomic alterations and tumor cell surface proteins in patients with non-small cell lung cancer (NSCLC). However, utilization remains suboptimal, representing missed treatment opportunities. This study aimed to identify challenges and potential solutions to obtaining percutaneous lung needle biopsy specimens for successful molecular testing in patients with advanced NSCLC. METHODS: This interdisciplinary qualitative study included ten radiologists and four pathologists from academic and community settings across the United States who routinely perform and analyze percutaneous lung needle biopsies. Participants underwent semi-structured one-on-one interviews (Phase 1). Interview questionnaires were constructed based on a literature review of key lines of inquiry and conducted by professional market researchers using the theoretical domains framework. Primary barriers to molecular testing were identified using thematic analysis. Subsequently, multidisciplinary focus groups were convened to identify potential solutions (Phase 2). RESULTS: Four themes emerged as barriers to molecular testing and were matched to the clinical workflow: (1) biopsy request, (2) biopsy procedure, (3) specimen analysis, and (4) communication. The nineteen potential solutions included adding a "checkbox" to indicate molecular testing in the biopsy request, leveraging pre-procedural imaging to guide biopsies, conserving tissue through appropriate allocation strategies and next generation sequencing panels instead of sequential single-gene assays, instituting reflex-molecular testing upon NSCLC diagnosis, tracking and communicating biopsy outcomes at multidisciplinary tumor boards, and improving integration of radiologists and pathologists into oncology care teams. CONCLUSIONS: Potential solutions exist to increase successful molecular testing of lung needle biopsy specimens in patients with advanced NSCLC.

The association of prostatic lipids with progression, racial disparity and discovery of biomarkers in prostate cancer.

BACKGROUND: It remains under-investigated whether prostatic lipid profiles are associated with pathogenesis, progression, racial disparity, and discovery of biomarkers in prostate cancer (PCa). METHODS: The electrospray ionization-tandem mass spectrometry was applied to quantitate prostatic lipids in human and mouse PCa and non-cancer prostatic tissues. Biostatistics and bioinformatics were used to compare the concentrations of prostatic lipids at levels of total lipid, group, class and individual species between PCa and benign prostatic tissues, between races, and among pathological conditions of PCa. RESULTS: Prostatic concentrations of total lipids as well as neutral lipids were significantly higher in PCa than in benign prostatic tissues in all population and Caucasian American population, but not in African American population. The prostatic phospholipid were not statistically different between PCa and benign prostatic tissues in all study populations. Cholesteryl ester is the only lipid class significantly higher in PCa than in benign prostatic tissues in all study populations. A panel of prostatic lipid parameters in each study population was identified as diagnostic and prognostic biomarkers with >60% of sensitivity, specificity and accuracy simultaneously. Lipid profiling on mouse prostatic tissues further confirmed correlation of prostatic lipid profiles to the pathogenesis and progression of PCa. In addition, a few prostatic lipids in mouse can serve as prognostic biomarkers in differentiation of indolent from aggressive PCa. CONCLUSION: The prostatic lipids are widely associated with the pathogenesis, progression and racial disparity of PCa. A panel of prostatic lipids can serve as diagnostic, prognostic and race-specific biomarkers for PCa.

Adherence to National Comprehensive Cancer Network ALK Testing Guidelines for Patients with Advanced Non-Small Cell Lung Cancer in U.S. Community Medical Centers.

BACKGROUND: National Comprehensive Cancer Network (NCCN) guidelines recommend biomarker testing as the first step in the management of patients with advanced non-small cell lung cancer (aNSCLC). We assessed anaplastic lymphoma kinase (ALK) testing rates and factors related to underuse in community medical systems between 2012 and 2019 to understand guideline adoption. METHODS: A retrospective observational study using a nationwide electronic health record (EHR)-derived deidentified database was conducted. Patients with aNSCLC diagnosed in community medical centers from January 2012 to May 2019 were included to describe the ALK testing trend. This cohort was further restricted to patients diagnosed after 2015 to understand factors associated with testing underuse using mixed-effects multivariable logistic regression models. RESULTS: Trends for increased ALK testing rates by year were observed in both NCCN guideline-eligible patients (59.5% in 2012 to 84.1% in 2019) and -ineligible patients (15.6% to 50.8%) in a cohort of 41,728 patients. Histology type and smoking status had the greatest impact on test use. Compared with patients with nonsquamous histology and no smoking history, patients with squamous histology and no smoking history (adjusted odds ratio [aOR], 7.6; 95% confidence interval [CI], 5.6-10.4), NSCLC histology not otherwise specified (NOS) with smoking history (aOR, 3.4; 95% CI, 2.8-4.2); NSCLC NOS/nonsmoker (aOR, 1.8; 95% CI, 1.1-3.2), and nonsquamous/smoker (aOR, 1.5; 95% CI, 1.3-1.7) were less likely to be tested. Factors related to underuse also included Eastern Cooperative Oncology Group performance status, stage at initial diagnosis, and demographics. CONCLUSION: This analysis of real-world data shows increasing test use by year; however, one fifth of patients eligible for ALK testing still remain untested and potentially missing therapeutic options. IMPLICATIONS FOR PRACTICE: Advancement in treatment of lung cancer is accompanied by an increasing number of tests that should be run to determine potential therapy options for each patient. This study assessed adoption of testing recommendations for anaplastic lymphoma kinase rearrangements in a national database. Although test use increased over the time period studied (2012-2019), there is still room for improvement. Efforts are needed to increase test use in undertested groups, thus enabling eligible patients to benefit from novel lung cancer therapies.

Micropapillary adenocarcinoma of lung: Morphological criteria and diagnostic reproducibility among pulmonary pathologists.

CONTEXT: Invasive micropapillary adenocarcinoma (MPC) is an aggressive variant of lung adenocarcinoma, frequently manifesting with advanced stage lymph node metastasis and decreased survival. OBJECTIVE: Identification of this morphology is important, as it is strongly correlated with poor prognosis regardless of the amount of MPC component. To date, no study has investigated the morphological criteria used to objectively diagnose it. DESIGN: Herein, we selected 30 cases of potential MPC of lung, and distributed 2 digital images per case among 15 pulmonary pathology experts. Reviewers were requested to diagnostically interpret, assign the percentage of MPC component, and record the morphological features they identified. The noted features included: columnar cells, elongated slender cell nests, extensive stromal retraction, lumen formation with internal epithelial tufting, epithelial signet ring-like forms, intracytoplasmic vacuolization, multiple nests in the same alveolar space, back-to-back lacunar spaces, epithelial nest anastomosis, marked pleomorphism, peripherally oriented nuclei, randomly distributed nuclei, small/medium/large tumor nest size, fibrovascular cores, and spread through air-spaces (STAS). RESULTS: Cluster analysis revealed three subgroups with the following diagnoses: "MPC", "combined papillary and MPC", and "others". The subgroups correlated with the reported median percentage of MPC. Intracytoplasmic vacuolization, epithelial nest anastomosis/confluence, multiple nests in the same alveolar space, and small/medium tumor nest size were the most common criteria identified in the cases diagnosed as MPC. Peripherally oriented nuclei and epithelial signet ring-like forms were frequently identified in both the "MPC" and "combined papillary and MPC" groups. CONCLUSIONS: Our study provides objective diagnostic criteria to diagnose MPC of lung.

Interpathologist Diagnostic Agreement for Non-Small Cell Lung Carcinomas Using Current and Recent Classifications.

CONTEXT.­: Measurement of interpathologist diagnostic agreement (IPDA) should allow pathologists to improve current diagnostic criteria and disease classifications. OBJECTIVES.­: To determine how IPDA for pathologists' diagnoses of non-small cell lung carcinoma (NSCLC) is affected by the addition of a set of mucin and immunohistochemical (IHC) stains to hematoxylin-eosin (H&E) alone, by recent NSCLC reclassifications, by simplification of these classifications, and by pathologists' practice location, pulmonary pathology expertise, practice duration, and lung carcinoma case exposure. DESIGN.­: We used a Web-based survey to present core images of 54 NSCLC cases to 22 practicing pathologists for diagnosis, initially as H&E only, then as H&E plus mucin and 4 IHC stains. Each case was diagnosed according to published 2004, 2011, and 2015 NSCLC classifications. Cohen's kappa was calculated for the 231 pathologist pairs as a measure of IPDA. RESULTS.­: Twenty-two pathologists diagnosed 54 NSCLC cases by using 4 published classifications. IPDA is significantly higher for H&E/mucin/IHC diagnoses than for H&E-only diagnoses. IPDA for H&E/mucin/IHC diagnoses is highest with the 2015 classification. IPDA is estimated higher after collapse of stated diagnoses into subhead or dichotomized classes. IPDA for H&E/mucin/IHC diagnoses with the 2015 World Health Organization classification is similar for community and academic pathologists, and is higher when pathologists have pulmonary pathology expertise, have more than 6 years of practice experience, or diagnose more than 100 new lung carcinoma cases per year. CONCLUSIONS.­: Higher IPDA is associated with use of mucin and IHC stains, with the 2015 NSCLC classification, and with pathologists' pulmonary pathology expertise, practice duration, and frequency of lung carcinoma cases.

Impact of Recent Developments in Lung Cancer on the Practice of Pathology.

Landmark events in the field of lung cancer in the past year have the potential to significantly alter the practice of pathology. Three key events are (1) approval of payment for low-dose computed tomography screening for lung cancer, (2) publication of an extensively revised World Health Organization classification of lung cancers, and (3) approval of immunohistochemistry based companion diagnostics by the US Food and Drug Administration. We briefly review these milestones in the context of their impact on the practice of pathology.

Intrapleural adenoviral delivery of human plasminogen activator inhibitor-1 exacerbates tetracycline-induced pleural injury in rabbits.

Elevated concentrations of plasminogen activator inhibitor-1 (PAI-1) are associated with pleural injury, but its effects on pleural organization remain unclear. A method of adenovirus-mediated delivery of genes of interest (expressed under a cytomegalovirus promoter) to rabbit pleura was developed and used with lacZ and human (h) PAI-1. Histology, ß-galactosidase staining, Western blotting, enzymatic and immunohistochemical analyses of pleural fluids (PFs), lavages, and pleural mesothelial cells were used to evaluate the efficiency and effects of transduction. Transduction was selective and limited to the pleural mesothelial monolayer. The intrapleural expression of both genes was transient, with their peak expression at 4 to 5 days. On Day 5, hPAI-1 (40-80 and 200-400 nM of active and total hPAI-1 in lavages, respectively) caused no overt pleural injury, effusions, or fibrosis. The adenovirus-mediated delivery of hPAI-1 with subsequent tetracycline-induced pleural injury resulted in a significant exacerbation of the pleural fibrosis observed on Day 5 (P = 0.029 and P = 0.021 versus vehicle and adenoviral control samples, respectively). Intrapleural fibrinolytic therapy (IPFT) with plasminogen activators was effective in both animals overexpressing hPAI-1 and control animals with tetracycline injury alone. An increase in intrapleural active PAI-1 (from 10-15 nM in control animals to 20-40 nM in hPAI-1-overexpressing animals) resulted in the increased formation of PAI-1/plasminogen activator complexes in vivo. The decrease in intrapleural plasminogen-activating activity observed at 10 to 40 minutes after IPFT correlates linearly with the initial concentration of active PAI-1. Therefore, active PAI-1 in PFs affects the outcome of IPFT, and may be both a biomarker of pleural injury and a molecular target for its treatment.

Novel aspects of urokinase function in the injured lung: role of α2-macroglobulin.

The level of active urokinase (uPA) is decreased in lung fluids of patients with acute lung injury/acute respiratory distress syndrome (ALI/ARDS) whereas α(2)-macroglobulin (α(2)-M), a plasma proteinase inhibitor, is a major component of these fluids. Since there have been reports describing the ability of α(2)-M to form complexes with uPA in vitro, we hypothesized that α(2)-M may interact with uPA in the lung to modulate its biological activity. Pulmonary edema fluids and lung tissues from patients with ALI/ARDS were evaluated for the presence of uPA associated with α(2)-M. Complexes between α(2)-M and uPA were detected in alveolar edema fluids as well as in lungs of patients with ALI/ARDS where they were located mainly in close proximity to epithelial cells. While uPA bound to α(2)-M retains its amidolytic activity towards low-molecular-weight substrates, it is not inhibited by its main physiological inhibitor, plasminogen activator inhibitor 1. We also investigated the functional consequences of formation of complexes between uPA and α(2)-M in vitro. We found that when α(2)-M:uPA complexes were added to cultures of human bronchial epithelial cells (BEAS-2B), activation of nuclear factor-κB as well as production of interleukin-6 and -8 was substantially suppressed compared with the addition of uPA alone. Our findings indicate for the first time that the function of uPA in patients with ALI/ARDS may be modulated by α(2)-M and that the effects may include the regulation of the fibrinolytic and signaling activities of uPA.

Revolution in lung cancer: new challenges for the surgical pathologist.

CONTEXT: Traditionally, lung cancer has been viewed as an aggressive, relentlessly progressive disease with few treatment options and poor survival. The traditional role of the pathologist has been primarily to differentiate small cell carcinoma from non-small cell carcinoma on biopsy and cytology specimens and to stage non-small cell carcinomas that underwent resection. In recent years, our concepts of lung cancer have undergone a revolution, including (1) the advent of successful, new, molecular-targeted therapies for lung cancer, many of which are associated with specific histologic cell types and subtypes; (2) new observations on the natural history of lung cancer derived from ongoing high-resolution computed tomography screening studies and recent histologic findings; and (3) proposals to revise the classification of lung cancers, particularly adenocarcinomas, in part because of the first 2 developments. OBJECTIVE: To summarize the important, new developments in lung cancer, emphasizing the role of the surgical pathologist in personalized care for patients with lung cancer. DATA SOURCES: Information about the new developments in lung cancer was obtained from the peer-review medical literature and the authors' experiences. CONCLUSIONS: For decades, we have perceived lung cancer as a relentlessly aggressive and mostly incurable disease for which the surgical pathologist had a limited role. Today, surgical pathologists have an important and expanding role in the diagnosis and treatment of lung cancer, and it is essential to keep informed of new advances.

Neutrophil alpha-defensins cause lung injury by disrupting the capillary-epithelial barrier.

RATIONALE: The involvement of neutrophil activation in the sentinel, potentially reversible, events in the pathogenesis of acute lung injury (ALI) is only partially understood. alpha-Defensins are the most abundant proteins secreted by activated human neutrophils, but their contribution to ALI in mouse models is hindered by their absence from murine neutrophils and the inability to study their effects in isolation in other species. OBJECTIVES: To study the role of alpha-defensins in the pathogenesis of ALI in a clinically relevant setting using mice transgenic for polymorphonuclear leukocyte expression of alpha-defensins. METHODS: Transgenic mice expressing polymorphonuclear leukocyte alpha-defensins were generated. ALI was induced by acid aspiration. Pulmonary vascular permeability was studied in vivo using labeled dextran and fibrin deposition. The role of the low-density lipoprotein-related receptor (LRP) in permeability was examined. MEASUREMENTS AND MAIN RESULTS: Acid aspiration induced neutrophil migration and release of alpha-defensins into lung parenchyma and airways. ALI was more severe in alpha-defensin-expressing mice than in wild-type mice, as determined by inspection, influx of neutrophils into the interstitial space and airways, histological evidence of epithelial injury, interstitial edema, extravascular fibrin deposition, impaired oxygenation, and reduced survival. Within 4 hours of insult, alpha-defensin-expressing mice showed greater disruption of capillary-epithelial barrier function and ALI that was attenuated by systemic or intratracheal administration of specific inhibitors of the LRP. CONCLUSIONS: alpha-Defensins mediate ALI through LRP-mediated loss of capillary-epithelial barrier function, suggesting a potential new approach to intervention.

Anti-chemokine autoantibody:chemokine immune complexes activate endothelial cells via IgG receptors.

Our previous studies revealed that the presence in lung fluids of anti-IL-8 autoantibody:IL-8 immune complexes is an important prognostic indicator for the development and outcome of acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). Anti-IL-8:IL-8 complexes purified from lung edema fluids trigger chemotaxis of neutrophils, induce activation of these cells, and regulate their apoptosis, all via IgG receptor, FcgammaRIIa. Importantly, increased levels of FcgammaRIIa are present in lungs of patients with ARDS, where FcgammaRIIa is partially associated with anti-IL-8:IL-8 complexes. In the current study, we demonstrate the ability of anti-IL-8:IL-8 complexes to promote an inflammatory phenotype of human umbilical vein endothelial cells via interaction with FcgammaRIIa. Human umbilical vein endothelial cells cultured in the presence of the complexes become activated, as shown by increased phosphorylation of ERK, JNK, and Akt, and augmented nuclear translocation of NF-kappaB. Anti-IL-8:IL-8 complexes also up-regulate expression of intracellular adhesion molecule (ICAM)-1 on the cell surface. Furthermore, we detected increased levels of ICAM-1 on lung endothelial cells from mice in which lung injury was induced by generating immune complexes in alveolar spaces. On the other hand, ICAM-1 expression was unchanged in lungs of gamma chain-deficient mice, lacking receptors that interact with immune complexes. Moreover, in lung tissues from patients with ARDS, anti-IL-8:IL-8 complexes were associated with endothelial cells that expressed higher levels of ICAM-1. Our current findings implicate that anti-chemokine autoantibody:chemokine immune complexes, such as IL-8:IL-8 complexes, may contribute to pathogenesis of lung inflammation by inducing activation of endothelial cells through engagement of IgG receptors.

Pulmonary epithelioid hemangioendothelioma mimicking mesothelioma.

An intrathoracic mass was discovered on magnetic resonance imaging (MRI) of the spine in a 37-year-old Caucasian man with a 1 year history of progressively severe upper back pain. A subsequent chest CT scan indicated a 4 cm left hilar mass, extending to the apex and encasing a portion of the left bronchus and pulmonary artery. Initial bronchoscopic and transthoracic biopsies failed to obtain diagnostic material. The patient underwent thoracotomy and was found to have a locally advanced, surgically unresectable lung tumor, involving the pleura, pericardium and diaphragm. The patient failed to respond to radiochemotherapy, and died 11 months following the diagnosis with tamponade and metastasis to the skin of the thoracoabdominal wall. Histologically the tumor had an epithelioid and spindled appearance, without high-grade histological features, and was initially thought to represent biphasic diffuse malignant mesothelioma. Positive immunohistochemistry for vascular markers (CD31, CD34, and FLI-1) disclosed the vascular nature of the tumor. Mesothelioma markers were universally negative and cytokeratin was focally reactive only in some epithelioid cells. Epithelioid hemangioendothelioma is a rare tumor in the lung that can mimic other more common pathological entities, and should be included in the differential diagnosis of unusual pulmonary neoplasms with epithelioid or biphasic morphology.

Anti-IL-8 autoantibody:IL-8 immune complexes suppress spontaneous apoptosis of neutrophils.

Our previous studies demonstrated that a significant fraction of interleukin-8 (IL-8) in lung fluids from patients with acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS) is associated with anti-IL-8 autoantibodies (anti-IL-8:IL-8 immune complexes). Neutrophils have been implicated in the pathogenesis of ALI/ARDS, and moreover, it is well-established that apoptosis of neutrophils is delayed in patients with ALI/ARDS. The aim of this study was, therefore, to examine the role of anti-IL-8:IL-8 immune complexes in modulating spontaneous apoptosis of normal human neutrophils. Apoptosis was assessed by evaluating morphological changes, measuring enzymatic activity of caspase-3, and determining the extent of DNA degradation. We found that samples containing anti-IL-8:IL-8 immune complexes but not samples from which these complexes were removed inhibited neutrophil apoptosis. Furthermore, the former samples or effectively anti-IL-8:IL-8 complexes induced an increase in the level of antiapoptotic protein, Bcl-X(L). In contrast, levels of proapoptotic proteins Bax and Bak were decreased in the same conditions. Activity of both caspase-3 and caspase-9 was also suppressed by anti-IL-8:IL-8 complex-containing samples. Finally, we established that IgG receptor, FcgammaRIIa, mediates antiapoptotic activity of anti-IL-8:IL-8 complexes and that the key components of the FcgammaRIIa signaling pathway, Src, Syk, PI3 kinase, and ERK, may be involved in regulation of neutrophil apoptosis by the complexes. These studies demonstrate for the first time that anti-IL-8:IL-8 immune complexes have the ability to prolong neutrophil life.

MUC4 expression in non-small cell lung carcinomas: relationship to tumor histology and patient survival.

CONTEXT: Mucin 4 (MUC4) is a high-molecular-weight membrane-bound glycoprotein that is expressed in the foregut before epithelial differentiation. It is found in normal adult airway epithelium, non-small cell lung carcinoma (NSCLC) and in other human malignancies independent of mucus secretion. Although its tissue distribution has been studied, its utility in predicting prognosis in NSCLC is unknown. OBJECTIVE: To evaluate the relationship between MUC4 overexpression and long-term survival in patients with NSCLC. DESIGN: Immunohistochemical staining for MUC4 was performed on formalin-fixed, paraffin-embedded tissue samples from 343 cases of NSCLC arranged in a high-density tissue microarray. Information about long-term survival and tumor stage was collected for all patients. Semiquantitative assessment of MUC4 staining was correlated with survival (Kaplan-Meier analysis). RESULTS: MUC4 was frequently expressed in adenocarcinomas (151/187 [81%]), squamous cell carcinomas (69/ 88 [78%]), adenosquamous carcinomas (6/8 [75%]), and large cell carcinomas (33/60 [55%]). High levels of expression (combined score, 2+/3+) for MUC4 were more characteristic of adenocarcinomas (126/187 [68%]) and adenosquamous carcinomas (6/8 [75%]) than of squamous cell carcinomas (46/88 [52%]) and large cell carcinomas (17/60 [28%]) (P < .001). In patients with stage I and II adenocarcinoma, there was a trend toward longer patient survival with higher levels of MUC4 immunoreactivity compared with lower levels (P = .11). CONCLUSION: MUC4 expression is common in pulmonary adenocarcinomas and may indicate a more favorable prognosis in early-stage adenocarcinomas.

Expression of glutathione S-transferase pi and glutathione synthase correlates with survival in early stage non-small cell carcinomas of the lung.

The glutathione S-transferase (GST) family of genes encode for detoxification enzymes that protect against reactive oxygen species and influence host susceptibility to carcinogens, including tobacco smoke. It has not been determined whether isoenzyme GST-pi or glutathione synthase (GSH2) expression by tumor cells bears a relationship to survival. A total of 201 non-small cell lung cancers (NSCLC) with long-term follow-up were immunostained with antibodies to GST-pi and GSH2 using standard immunostaining techniques. Results were graded semiquantitatively using a scale of 0 to 3 (0 < or = 10%; 1 = 10%-50%; 2 = 51%-80%; 3 > or = 80%) for both nuclear and cytoplasmic staining. Results were correlated with patient survival using Kaplan-Meier analysis. Nuclear staining with GST-pi in greater than 10% of the cells was closely associated with decreased survival (P = .02) in stage I and II squamous cell carcinomas (n = 40). Cytoplasmic staining showed a similar trend that did not reach statistical significance. No significant correlation between GST-pi staining and survival was determined for other histologic types of NSCLC. Cytoplasmic GSH2 staining in greater than 80% of tumor cells was associated with a trend toward improved survival for stage I adenocarcinoma (P = .08) but did not show a relationship to survival for other histologic types of NSCLC. GST-pi expression predicts prognosis in stage I and II squamous cell lung carcinoma, and GSH2 expression may indicate better survival in early stage adenocarcinoma of the lung. Manipulation of GST-pi and GSH2 may be a potential basis for treatment of some NSCLC.

Expression of renal cell carcinoma-associated markers erythropoietin, CD10, and renal cell carcinoma marker in diffuse malignant mesothelioma and metastatic renal cell carcinoma.

CONTEXT: Metastatic renal cell carcinoma (MRCC) involving the thorax can be difficult to distinguish from diffuse malignant mesothelioma (DMM) using traditional morphologic approaches. Standard panels of immunohistochemical markers are of limited benefit. OBJECTIVE: To investigate several antibodies to renal cell carcinoma-associated proteins for differentiating MRCC from DMM. DESIGN: One hundred DMMs and 20 MRCCs were evaluated for immunoexpression of erythropoietin. The same cases and an additional 45 DMMs were evaluated for CD10 and renal cell carcinoma marker (RCCMa) immunoreactivity. RESULTS: Erythropoietin was expressed in 100% of DMMs and MRCCs. Staining for CD10 was observed in 54% of DMMs and 100% of MRCCs. RCCMa stained 26% of DMMs and 55% of MRCCs. Although erythropoietin staining was similarly strong and diffuse in both DMM and MRC, patterns of staining for RCCMa and CD10 differed between MRCC and DMM. Immunoreactivity was strong and diffuse for both RCCMa and CD10 in most MRCCs. Of CD10-positive DMMs, nearly half showed staining in less than 50% of tumor cells and about one fourth of positive cases exhibited only weak to moderately intense staining. Only half of RCCMa-positive DMMs showed staining in more than 49% of tumor cells and staining was only weak to moderately intense in most cases. CONCLUSIONS: Given the overlap in the expression of renal cell carcinoma markers in MRCC and DMM, results with these markers must be interpreted cautiously and should be used in conjunction with mesothelium-associated markers. Differences in expression may potentially help distinguish MRCC from DMM inasmuch as strong and diffuse expression of RCCMa and CD10 supports a diagnosis of MRCC over DMM.

Silicone thorax due to a ruptured breast implant.

A woman with a history of bilateral mastectomy and silicone implants for fibrocystic disease and a history of atrial septal defect repair presented with pleural nodules on a chest radiograph. A thorascopic biopsy performed for possible mesothelioma demonstrated chronic inflammation and focal pleural fibrosis due to a foreign-body reaction secondary to silicone. This was confirmed using scanning electron microscopy and energy-dispersive radiograph elemental analysis. As the population ages, the increasing frequency of ruptured silicone implants and the need for heart surgery may result in a corresponding increase in the risk for fibrothorax secondary to inadvertent silicone introduction during surgery.

Distinction of pulmonary small cell carcinoma from poorly differentiated squamous cell carcinoma: an immunohistochemical approach.

Accurate morphologic distinction between small cell carcinoma and poorly differentiated squamous cell carcinoma has critical therapeutic significance, but can be limited by crush artifact, tumor necrosis, limited tumor representation, and overlapping morphologic features. We evaluated a panel of antibodies for their efficacy in distinguishing between these neoplasms. Formalin-fixed paraffin-embedded tissue sections of small cell carcinomas and poorly differentiated squamous cell carcinomas underwent immunohistochemical staining with antibodies to thyroid transcription factor-1, p63, high molecular weight keratin, and p16(INK4A). Of 28 small cell carcinomas, 26 (93%) small cell carcinomas showed diffuse moderate or strong staining for thyroid transcription factor-1 with no staining for high molecular weight keratin and p63. In contrast, 27/28 (96%) poorly differentiated squamous cell carcinomas manifested opposite immunoreactivities, with diffuse moderate or strong staining for high molecular weight keratin and p63, and no or minimal staining for thyroid transcription factor-1. In two additional cases originally interpreted as small cell carcinoma, high molecular weight keratin highlighted small numbers of neoplastic large cells, leading to reclassification as combined small cell and non-small cell carcinomas. p16(INK4A) expression varied widely in poorly differentiated squamous cell carcinomas, but was consistently moderate or strong and diffuse in small cell carcinomas, and proved helpful in the two thyroid transcription factor-1-negative small cell carcinomas. This study demonstrates that a panel consisting of antibodies to thyroid transcription factor-1, p63, high molecular weight keratin, and p16(INK4A) is highly effective for distinguishing between small cell carcinoma and poorly differentiated squamous cell carcinoma. This panel also facilitates diagnosis of combined small cell and non-small cell carcinomas.