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.

Tissue Continues to Be the Issue: Role of Histopathology in the Context of Recent Updates in the Radiologic Classification of Interstitial Lung Diseases.

CONTEXT.­: High-resolution computed tomography (HRCT) imaging has an increasingly important role in clinical decision-making in patients with interstitial lung diseases. The recent Fleischner Society white paper on the diagnostic criteria for idiopathic pulmonary fibrosis highlights the advances in our understanding of HRCT imaging in interstitial lung diseases. OBJECTIVE.­: To discuss the evidence and recommendations outlined in the white paper as it pertains to the radiologic diagnosis of interstitial lung disease, specifically highlighting the current limitations of HRCT in confidently predicting histopathologic findings. DATA SOURCES.­: The recent Fleischner Society white paper and other studies pertaining to the role of HRCT in predicting histopathology in interstitial lung diseases are reviewed. CONCLUSIONS.­: High-resolution computed tomography is highly predictive of a usual interstitial pneumonia (UIP) pattern on histopathology when the HRCT shows a typical UIP pattern on a "confident" read by the radiologist. A probable UIP pattern is also very predictive of a UIP pattern on histopathology, and histopathologic confirmation is not needed for most patients demonstrating this pattern in the appropriate clinical setting. A UIP pattern may be seen in a substantial proportion of patients with an "indeterminate UIP" pattern on HRCT and in many patients for whom the HRCT suggests an alternative diagnosis; histopathologic confirmation should be considered in patients demonstrating these patterns whenever feasible.

Association of Tumor Mutational Burden With DNA Repair Mutations and Response to Anti-PD-1/PD-L1 Therapy in Non-Small-Cell Lung Cancer.

PURPOSE: To examine clinical predictors of tumor mutational burden (TMB), to explore the association between TMB and DNA repair mutations, and to analyze TMB as a biomarker for response to immune checkpoint blockade in non-small-cell lung cancer. PATIENTS AND METHODS: TMB scores were determined retrospectively for 72 consecutive patients at our institution with next-generation sequencing comprehensive genomic profiling testing by Foundation Medicine. TMB scores were correlated with a number of clinical variables and presence of DNA repair mutations. Thirty-four patients were treated with anti-programmed cell death 1 (PD-1)/programmed death ligand 1 (PD-L1) therapies, and survival analyses based on TMB score were performed. In addition, tissue immunohistochemical analysis was performed for a subset of patients. RESULTS: History of smoking, but not other clinical variables, including prior treatment lines, stage of disease, and number of metastatic sites, predicted higher TMB score. Higher TMB score was significantly associated with greater number of DNA repair mutations. In the subset of patients treated with immune checkpoint blockade, higher TMB score significantly predicted overall survival, but not progression-free survival (hazard ratio = 0.10, P = .003; hazard ratio 1.1, P = .84, respectively). In a small subset of patients, PD-1/PD-L1 staining did not independently predict progression-free survival or overall survival. CONCLUSION: Tissue TMB was significantly associated with smoking history and number of DNA repair mutations. TMB is a promising biomarker for response to anti-PD-1/PD-L1 therapy, with higher TMB score predicting longer overall survival.

High Frequency of MYD88 L265P Mutation in Primary Ocular Adnexal Marginal Zone Lymphoma and Its Clinicopathologic Correlation: A Study From a Single Institution.

CONTEXT.­: The pathogenesis of primary ocular adnexal marginal zone lymphoma (POAMZL) remains unclear. The reported associations with Chlamydia psittaci infection and MYD88 mutations are highly variable. OBJECTIVE.­: To examine MYD88 L265P mutation in ocular marginal zone lymphomas and correlate with clinicopathologic features and Chlamydia infection. DESIGN.­: Presence of MYD88 L265P mutation and Chlamydia infection in lymphoma was analyzed by using sensitive polymerase chain reaction (PCR) methods. RESULTS.­: The MYD88 L265P mutation was identified in 8 of 22 POAMZLs (36%), including 2 of 3 cases in which PCR failed to detect clonal IGH gene rearrangement; none of the 4 secondary marginal zone lymphomas were positive. Test results for Chlamydia were negative in all cases. Patients with and without the MYD88 mutation had similar clinicopathologic features. CONCLUSIONS.­: The MYD88 mutational analysis provides important information in diagnostic workup of POAMZL. The frequent MYD88 mutation suggests a critical role of this aberration in the pathogenesis of POAMZL and may serve as a therapeutic target for patients with progressive disease.

Rhinoscleroma.

CONTEXT.­: Rhinoscleroma is a rare, chronic, infectious granulomatous process involving the upper respiratory tract caused by gram-negative bacilli, Klebsiella rhinoscleromatis. The site most commonly affected is the nasopharynx; however, lesions in various other locations have been described. OBJECTIVE.­: To review the literature for all the reported cases of rhinoscleroma in the past 5 years. DATA SOURCES.­: Published cases of rhinoscleroma from a PubMed (National Center for Biotechnology Information, Bethesda, Maryland) search were reviewed. CONCLUSIONS.­: Rhinoscleroma in nonendemic regions is extremely rare; however, with increased travel, immigration, and globalization, it is imperative to recognize this entity because the symptoms can be devastating and in some cases fatal. Although nasopharynx is the common site of involvement, unusual sites such as the trachea can be involved in rare cases. Rhinoscleroma can be managed effectively with a combination of antibiotics and surgical debridement and repair; however, recurrence rates do remain high.

TLR4-dependent fibroblast activation drives persistent organ fibrosis in skin and lung.

Persistent fibrosis in multiple organs is the hallmark of systemic sclerosis (SSc). Recent genetic and genomic studies implicate TLRs and their damage-associated molecular pattern (DAMP) endogenous ligands in fibrosis. To test the hypothesis that TLR4 and its coreceptor myeloid differentiation 2 (MD2) drive fibrosis persistence, we measured MD2/TLR4 signaling in tissues from patients with fibrotic SSc, and we examined the impact of MD2 targeting using a potentially novel small molecule. Levels of MD2 and TLR4, and a TLR4-responsive gene signature, were enhanced in SSc skin biopsies. We developed a small molecule that selectively blocks MD2, which is uniquely required for TLR4 signaling. Targeting MD2/TLR4 abrogated inducible and constitutive myofibroblast transformation and matrix remodeling in fibroblast monolayers, as well as in 3-D scleroderma skin equivalents and human skin explants. Moreover, the selective TLR4 inhibitor prevented organ fibrosis in several preclinical disease models and mouse strains, and it reversed preexisting fibrosis. Fibroblast-specific deletion of TLR4 in mice afforded substantial protection from skin and lung fibrosis. By comparing experimentally generated fibroblast TLR4 gene signatures with SSc skin biopsy gene expression datasets, we identified a subset of SSc patients displaying an activated TLR4 signature. Together, results from these human and mouse studies implicate MD2/TLR4-dependent fibroblast activation as a key driver of persistent organ fibrosis. The results suggest that SSc patients with high TLR4 activity might show optimal therapeutic response to selective inhibitors of MD2/TLR4 complex formation.

Isolated orbital mass as the primary presentation of a triple-hit lymphoma transformed from a systemic follicular lymphoma.

PURPOSE: Triple-hit lymphoma is a highly aggressive B-cell lymphoma. We report a case of triple-hit lymphoma transformed from systemic follicular lymphoma (FL) after 9-year remission and presented primarily as an isolated orbital mass without systemic symptoms or lymphadenopathy. OBSERVATIONS: A 58-year-old female presented with intermittent vertical binocular diplopia, left upper eyelid swelling and pain and was found to have a 2.9 cm orbital mass. Histological section revealed a CD10-positive large B-cell lymphoma, consistent with transformation of FL. Fluorescent in situ hybridization (FISH) analysis demonstrated rearrangements involving C-MYC, BCL-2 and BCL-6 genes, indicating a high grade, triple-hit lymphoma. CONCLUSIONS AND IMPORTANCE: Triple-hit lymphoma transformed from a low-grade lymphoma may initially present as an isolated orbital mass without systemic evidence of transformation. Early recognition of double or triple-hit lymphomas is important since these patients require aggressive chemotherapy.

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.

Immunohistochemistry of Pulmonary Biomarkers: A Perspective From Members of the Pulmonary Pathology Society.

The use of immunohistochemistry for the determination of pulmonary carcinoma biomarkers is a well-established and powerful technique. Immunohistochemisty is readily available in pathology laboratories, is relatively easy to perform and assess, can provide clinically meaningful results very quickly, and is relatively inexpensive. Pulmonary predictive biomarkers provide results essential for timely and accurate therapeutic decision making; for patients with metastatic non-small cell lung cancer, predictive immunohistochemistry includes ALK and programmed death ligand-1 (PD-L1) (ROS1, EGFR in Europe) testing. Handling along proper methodologic lines is needed to ensure patients receive the most accurate and representative test outcomes.

Hypersensitivity Pneumonitis A Perspective From Members of the Pulmonary Pathology Society.

CONTEXT: - Hypersensitivity pneumonitis (HP) is a lung disease that develops in susceptible individuals after inhalational exposure to an organic antigen or chemical compound. Pathogenesis is attributed to a combination of type III (immune complex-mediated) and type IV (delayed) hypersensitivity reactions to the inciting agent. OBJECTIVE: - To provide an overview of the current status of the medical literature regarding hypersensitivity pneumonitis. DATA SOURCES: - A literature search was performed using PubMed and Google search engines. The terms "hypersensitivity pneumonitis" and "extrinsic allergic alveolitis" were used, with the search starting on January 9, 2017, and concluding March 8, 2017. CONCLUSIONS: - As a pathologist, it is important to consider hypersensitivity pneumonitis when examining lung specimens because it is often clinically and pathologically overlooked. Recognizing the often subtle findings and correlating them with the patient's history or suggesting a thorough clinical investigation of potential exposures can be of help in identifying the underlying condition so that the patient can be appropriately managed.

Rapid On-Site Evaluation of Endobronchial Ultrasound-Guided Transbronchial Needle Aspirations for the Diagnosis of Lung Cancer: A Perspective From Members of the Pulmonary Pathology Society.

CONTEXT: - Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has emerged as a very useful tool in the field of diagnostic respiratory cytology. Rapid on-site evaluation (ROSE) of EBUS-TBNA not only has the potential to improve diagnostic yield of the procedure but also to triage samples for predictive molecular testing to guide personalized treatments for lung cancer. OBJECTIVE: - To provide an overview of the current status of the literature regarding ROSE of EBUS-TBNA in the diagnosis of lung cancer. DATA SOURCES: - An electronic literature search in PubMed and Google databases was performed using the following key words: cytology, lung cancer, on-site evaluation, rapid on-site evaluation, and ROSE EBUS-TBNA. Only articles published in English were included in this review. CONCLUSIONS: - Rapid on-site evaluation can ensure that the targeted lesion is being sampled and can enable appropriate specimen triage. If available, it should be used with EBUS-TBNA in the diagnosis of lung cancer because it can minimize repeat procedures for additional desired testing (ie, molecular studies). Some studies have shown that ROSE does not adversely affect the number of aspirations, total procedure time of EBUS-TBNA, or the rate of postprocedure complications; it is also helpful in providing a preliminary diagnosis that can reduce the number of additional invasive procedures, such as mediastinoscopy. As EBUS technology continues to evolve, our knowledge of the role of ROSE in EBUS-TBNA for the diagnosis of lung cancer will also continue to grow and evolve.

Challenges and future of biomarker tests in the era of precision oncology: Can we rely on immunohistochemistry (IHC) or fluorescence in situ hybridization (FISH) to select the optimal patients for matched therapy?

Molecular techniques have improved our understanding of the pathogenesis of cancer development. These techniques have also fueled the rational development of targeted drugs for patient populations stratified by their genetic characteristics. These novel methods have changed the classic paradigm of diagnostic pathology; among them are IHC, FISH, polymerase chain reaction (PCR) and microarray technology. IHC and FISH detection methods for human epidermal growth factor receptor-2 (HER2), epidermal growth factor receptor (EGFR) and programmed death ligand-1 (PD-L1) were recently approved by the Food and Drug Administration (FDA) as routine clinical practice for cancer patients. Here, we discuss general challenges related to the predictive power of these molecular biomarkers for targeted therapy in cancer medicine. We will also discuss the prospects of utilizing new biomarkers for fibroblast growth factor receptor (FGFR) and hepatocyte growth factor receptor (cMET/MET) targeted therapies for developing new and robust predictive biomarkers in oncology.

Molecular and Immune Biomarkers in Acute Respiratory Distress Syndrome: A Perspective From Members of the Pulmonary Pathology Society.

Acute respiratory distress syndrome (ARDS) is a multifactorial syndrome with high morbidity and mortality rates, characterized by deficiency in gas exchange and lung mechanics that lead to hypoxemia, dyspnea, and respiratory failure. Histologically, ARDS is characterized by an acute, exudative phase, combining diffuse alveolar damage and noncardiogenic edema, followed by a later fibroproliferative phase. Despite an enhanced understanding of ARDS pathogenesis, the capacity to predict the development of ARDS and to risk-stratify patients with the disease remains limited. Biomarkers may help to identify patients at the greatest risk of developing ARDS, to evaluate response to therapy, to predict outcome, and to improve clinical trials. The ARDS pathogenesis is presented in this article, as well as concepts and information on biomarkers that are currently used clinically or are available for laboratory use by academic and practicing pathologists and the developing and validating of new assays, focusing on the assays' major biologic roles in lung injury and/or repair and to ultimately suggest innovative, therapeutic approaches.

Peritumoral cuffing by T-cell tumor-infiltrating lymphocytes distinguishes HPV-related oropharyngeal squamous cell carcinoma from oral cavity squamous cell carcinoma.

BACKGROUND: It is unclear why human papillomavirus (HPV)-related head and neck squamous cell carcinoma (HNSCC) has improved clinical behavior compared to HPV-negative HNSCC. We sought to better characterize the immune microenvironment of tongue cancers by examining the CD3 and CD8 TIL pattern in HPV-positive and HPV-negative tumors. METHODS: Histologic sections from 40 oral tongue and oropharyngeal cases were analyzed (n=21 HPV DNA-positive, n=19 HPV DNA-negative). CD3 and CD8 T-cell immunostaining were performed on whole-slide sections to quantify tumor-infiltrating lymphocyte (TIL) density and assess its morphology. RESULTS: A subset of cases (HPV-positive) displayed a unique TIL pattern consisting of circumferential peritumoral population T cells, which was absent in the HPV-negative cases. The presence of peritumoral cuffing was strongly predictive of improved recurrence-free survival compared to cases that lacked this morphologic pattern of immune infiltrate. Four HPV-positive cases lacked the pattern, including two cases with disease recurrence. CONCLUSIONS: For the first time, we show an architectural pattern of immune infiltrate in HNSCC is seen exclusively in HPV-positive patients with improved recurrence-free survival and suggests an organized host immunological response contributes to disease control.

A Small Case Series of Intravascular Large B-Cell Lymphoma with Unexpected Findings: Subset of Cases with Concomitant Extravascular Central Nervous System (CNS) Involvement Mimicking Primary CNS Lymphoma.

BACKGROUND: Intravascular large B-cell lymphoma (IVLBCL) is a rare type of extranodal lymphoma with growth mainly in the lumina of vessels. We studied a small series of IVLBCL and focused on its central nervous system (CNS) involvement. METHODS: Searching the medical records of Northwestern Memorial Hospital, we identified five cases of IVLBCL from January 2007 to January 2015. Clinical information, hematoxylin and eosin stained histologic slides and immunohistochemistry studies were reviewed for all cases. Polymerase chain reaction (PCR) analysis for the immunoglobulin (Ig) heavy and light chain gene rearrangement was performed on all five cases. RESULTS: Three of the five cases of IVLBCL were autopsies. Patients' age ranged from 56 to 84. CNS involvement was present in two cases-in both patients, the CNS involvement showed an extravascular pattern with confluent sheet-like formation. PCR analysis confirmed that in one case the systemic intravascular and CNS extravascular components were clonally identical. CONCLUSIONS: In a small case series of IVLBCL, we observed that CNS involvement by IVLBCL often has an extravascular morphology, but is clonally identical to the intravascular counterpart by PCR analysis. As IVLBCL can have a rapidly progressing poor outcome, it should be kept in the differential diagnoses for patients presenting with lymphoma of the CNS. The presence of extravascular growth patterns in the CNS should not exclude IVLBCL as a diagnosis.

Diagnosis of Acute Cellular Rejection and Antibody-Mediated Rejection on Lung Transplant Biopsies: A Perspective From Members of the Pulmonary Pathology Society.

CONTEXT: - The diagnosis and grading of acute cellular and antibody-mediated rejection (AMR) in lung allograft biopsies is important because rejection can lead to acute graft dysfunction and/or failure and may contribute to chronic graft failure. While acute cellular rejection is well defined histologically, no reproducible specific features of AMR are currently identified. Therefore, a combination of clinical features, serology, histopathology, and immunologic findings is suggested for the diagnosis of AMR. OBJECTIVE: - To describe the perspective of members of the Pulmonary Pathology Society (PPS) on the workup of lung allograft transbronchial biopsy and the diagnosis of acute cellular rejection and AMR in lung transplant. DATA SOURCES: - Reports by the International Society for Heart and Lung Transplantation (ISHLT), experience of members of PPS who routinely review lung allograft biopsies, and search of literature database (PubMed). CONCLUSIONS: - Acute cellular rejection should be assessed and graded according to the 2007 working formulation of the ISHLT. As currently no specific features are known for AMR in lung allografts, the triple test (clinical allograft dysfunction, donor-specific antibodies, pathologic findings) should be used for its diagnosis. C4d staining might be performed when morphologic, clinical, and/or serologic features suggestive of AMR are identified.