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Justificación:La criobiopsia pulmonar transbronquial (TBLC) se ha propuesto como un método menos invasivo para obtener un diagnóstico tisular en pacientes con enfermedad pulmonar intersticial (EPI). El rendimiento diagnóstico de la TBLC en comparación con la biopsia pulmonar quirúrgica (SLB) sigue siendo incierto. Objetivos:Este estudio tuvo como objetivo determinar la precisión diagnóstica de la biopsia pulmonar transbronquial (TBLB) con fórceps y de la TBLC en comparación con la SLB para realizar el diagnóstico final con base en una discusión multidisciplinaria (MDD). Métodos:Los pacientes incluidos en el estudio se sometieron a TBLB y TBLC secuenciales, seguidas inmediatamente de SLB. Los casos, anonimizados y sin información sobre el método de biopsia, fueron revisados por un patólogo, quien trabajó a ciegas con respecto a dicha información, y luego discutidos en una conferencia multidisciplinaria. Resultados:Principales: Entre agosto de 2013 y octubre de 2017 se reclutaron 16 pacientes. La concordancia primaria entre TBLC y SLB para el diagnóstico final de MDD fue de 68.75%, con una kappa de Cohen de 0.6 (IC 95%: 0.39, 0.81). La concordancia primaria y la kappa de Cohen de la TBLC frente a la SLB para el diagnóstico final de MDD fueron mucho menores (50%, 0.21 [IC 95%: 0, 0.42] y 18.75%, 0.08 [IC 95%: -0.03, 0.19], respectivamente). La TBLC se asoció con hemorragia leve (hemorragia de grado 1, que requirió aspiración) en 56.2% de los pacientes. Conclusiones:En los pacientes con EPI de tipo incierto según con los datos clínicos y radiográficos, quienes requieren la toma de muestra de tejido para obtener un diagnóstico específico, la TBLC mostró una correlación moderada con la SLB al realizar el diagnóstico con la guía de una MDD. La TBLB mostró mala concordancia con los diagnósticos de la MDD, tanto mediante TBLC como por SLB.

Assessment of lung biopsies for the diagnosis of hypersensitivity pneumonitis (HP) is one of the most difficult diagnostic problems for surgical pathologists. It is a form of interstitial lung disease resulting from an immune reaction provoked by an inhaled antigen in susceptible individuals. Although this definition sounds simple, in practice, the diagnosis of HP can be challenging. To address these issues, the American College of Chest Physicians (CHEST) has recently published a guideline for the diagnosis of HP. In this review, we will explore the multidisciplinary diagnostic evaluation of HP with a focus on the pathologic features as outlined in the CHEST guidelines. The histologic criteria are divided into 4 diagnostic categories: (1) Typicalnonfibrotic HP or fibrotic HP; (2) Compatible withnonfibrotic HP or fibrotic HP; (3) Indeterminatefor nonfibrotic or fibrotic HP; and (4) Alternative Diagnosis.It is important to emphasize that patterns 1 to 3 do not represent discrete histologic entities or pathologic diagnoses. Rather, these categories are meant to serve as a practical guide for organizing a complex set of overlapping histologic patterns into an integrated diagnostic framework for facilitating multidisciplinary discussion. High-resolution computed tomography features are also summarized, emphasizing how the correlation of lung biopsies with computed tomography findings can help to favor the diagnosis, particularly in cases where biopsies are not typical for HP. This review highlights details of the histologic spectrum of HP as well as the utility of different types of biopsies and bronchoalveolar lavage. We also emphasize the importance of multidisciplinary discussion and the complex differential diagnosis.

Inflammatory bowel disease is associated with a wide spectrum of central, large, and small airway abnormalities, including bronchiectasis. The bronchiectasis associated with inflammatory bowel disease has a distinct phenotype, with marked inflammation and at times severe sterile bronchorrhea that can be responsive to inhaled corticosteroids.

SidE family of Legionellaeffectors catalyze non-canonical phosphoribosyl-linked ubiquitination (PR-ubiquitination) of host proteins during bacterial infection. SdeA localizes predominantly to ER and partially to the Golgi apparatus, and mediates serine ubiquitination of multiple ER and Golgi proteins. Here we show that SdeA causes disruption of Golgi integrity due to its ubiquitin ligase activity. The Golgi linking proteins GRASP55 and GRASP65 are PR-ubiquitinated on multiple serine residues, thus preventing their ability to cluster and form oligomeric structures. In addition, we found that the functional consequence of Golgi disruption is not linked to the recruitment of Golgi membranes to the growing Legionella-containing vacuoles. Instead, it affects the host secretory pathway. Taken together, our study sheds light on the Golgi manipulation strategy by which Legionellahijacks the secretory pathway and promotes bacterial infection.

Members of the Fleischner Society have compiled a glossary of terms for thoracic imaging that replaces previous glossaries published in 1984, 1996, and 2008, respectively. As with previous versions, the aim of the present glossary is to establish standardization of terminology for thoracic radiology and, thereby, to facilitate communications between radiologists and clinicians. Moreover, the present glossary aims to contribute to a more stringent use of terminology, increasingly required for structured reporting and accurate searches in large databases.

Light chain deposition disease, characterized by nonamyloidogenic deposits of immunoglobulin light chains, is rare in the lung and possibly underdiagnosed due to low clinical suspicion and lack of readily accessible tests. We encountered a case of pulmonary light chain deposition disease (PLCDD) in which light chain deposits appeared crimson red with a Masson trichrome (MT) stain and salmon pink with a sulfated Alcian blue (SAB) stain. This prompted us to characterize a series of PLCDD cases and assess the utility of MT and SAB stains to distinguish them from amyloidosis. From the pathology archives of 2 institutions spanning 10 years, we identified 11 cases of PLCDD, including 7 diagnosed as such and 4 determined retrospectively. The deposits in all cases of PLCDD stained crimson red with MT and salmon pink with SAB, while the cases of pulmonary amyloid (n=10) stained blue-gray and blue-green, respectively. The immunoglobulin light chain nature of the deposits was confirmed in 10 of 11 cases by either immunofluorescence microscopy (n=5) or mass spectrometry (n=5). Transmission electron microscopy revealed osmiophilic, electron-dense deposits in all cases analyzed (n=3). An extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue type was diagnosed in 10 cases and 1 represented a plasma cell neoplasm. Our study highlights the importance of considering PLCDD in the differential diagnosis of amyloid-like deposits in the lung and the value of performing MT and SAB stains to distinguish between PLCDD and amyloidosis.

Interstitial lung diseases are a heterogenous group of disorders that are often difficult to diagnose precisely. Clinical, laboratory, radiographic, and histologic information may be needed to arrive at the correct diagnosis. The multidisciplinary discussion has been proven to be useful in this patient group. Transbronchial cryobiopsy has become a popular method for obtaining tissue samples. Over the course of the last decade, there has been a significant amount of research assessing the feasibility, safety, and diagnostic endpoints of transbronchial cryobiopsy in patients with interstitial lung disease. Data continues to mount to support its use, which has been reflected in guidelines and expert panel reports. Patient selection, procedural performance, and appropriate specimen handling are critical factors for success. A coordinated approach by pulmonologists with expertise in interstitial lung diseases, interventional pulmonologists, and thoracic pathologists is essential. In this evidence-based narrative review, we address transbronchial cryobiopsies from these three distinct perspectives. In addition, the current literature was used to address nine common procedural questions.

Idiopathic pulmonary fibrosis (IPF) is a fibrotic disease with the histology of usual interstitial pneumonia (UIP). Although the pathologist's visual inspection is central in histologic assessments, three-dimensional microcomputed tomography (microCT) assessment may complement the pathologist's scoring. We examined associations between the histopathologic features of UIP and IPF in explanted lungs and quantitative microCT measurements, including alveolar surface density, total lung volume taken up by tissue (%), and terminal bronchiolar number. Sixty frozen samples from 10 air-inflated explanted lungs with severe IPF and 36 samples from 6 donor control lungs were scanned with microCT and processed for histologic analysis. An experienced pathologist scored three major UIP criteria (patchy fibrosis, honeycomb, and fibroblastic foci), five additional pathologic changes, and immunohistochemical staining for CD68-, CD4-, CD8-, and CD79a-positive cells, graded on a 0 to 3+ scale. The alveolar surface density and terminal bronchiolar number decreased and the tissue percentage increased in lungs with IPF compared with controls. In lungs with IPF, lower alveolar surface density and higher tissue percentage were correlated with greater scores of patchy fibrosis, fibroblastic foci, honeycomb, CD79a-positive cells, and lymphoid follicles. A decreased number of terminal bronchioles was correlated with honeycomb score but not with the other scores. The three-dimensional microCT measurements reflect the pathological UIP and IPF criteria and suggest that the reduction in the terminal bronchioles may be associated with honeycomb cyst formation.

Transbronchial lung cryobiopsy (TBLC) has been introduced recently in the diagnosis of interstitial lung diseases. We aimed to evaluate the prognostic significance of the distinction between idiopathic pulmonary fibrosis and other interstitial lung diseases with the use of TBLC data in multidisciplinary team (MDT) diagnosis.

The observation that patients with idiopathic pulmonary fibrosis (IPF) can have higher than normal expiratory flow rates at low lung volumes led to the conclusion that the airways are spared in IPF. This study aimed to re-examine the hypothesis that airways are spared in IPF using a multiresolution imaging protocol that combines multidetector CT (MDCT), with micro-CT and histology.

Transbronchial cryobiopsy (TBC) is increasingly recognized as a potential alternative to surgical lung biopsy (SLB) for the diagnosis of interstitial lung disease (ILD). The goal of this analysis was to examine the literature on TBC as it relates to diagnostic utility and safety to provide evidence-based and expert guidance to clinicians.

Transbronchial cryobiopsy, a new diagnostic procedure in patients with diffuse lung disease, provides larger and better-preserved lung specimens compared to forceps biopsy. The diagnostic yield of cryobiopsy is much better than that of forceps biopsy and slightly lower than that of surgical lung biopsy, but with a lower complication rate compared to the latter. Literature suggests that in the multidisciplinary approach to patients with diffuse lung disease cryobiopsy provides diagnostic and prognostic information similar to surgical lung biopsy. Cryobiopsy can also be performed in some patients unsuitable for surgical biopsy, yet in whom histologic input is needed.

In the appropriate clinical setting, the diagnosis of idiopathic pulmonary fibrosis (IPF) requires a pattern of usual interstitial pneumonia to be present on high-resolution chest CT (HRCT) or surgical lung biopsy. A molecular usual interstitial pneumonia signature can be identified by a machine learning algorithm in less-invasive transbronchial lung biopsy samples. We report prospective findings for the clinical validity and utility of this molecular test.

A 52-year-old, nonsmoking, African-American woman with a history of obesity, hypertension, and rheumatoid arthritis was referred for workup of multiple bilateral pulmonary nodules. The pulmonary nodules were discovered incidentally while undergoing a CT scan for an abdominal mass that was radiographically diagnosed as a uterine leiomyoma. She was asymptomatic from a pulmonary standpoint without unintentional weight loss, fevers, or night sweats. Her mother and sister had a history of lung cancer. She was diagnosed with rheumatoid arthritis 5 years earlier that was controlled with adalimumab for approximately 3 years when she stopped being seen by her rheumatologist and discontinued adalimumab. During evaluation for the abdominal mass, she re-established care with a rheumatologist and was started on 40 mg prednisone daily with plans to restart adalimumab once the workup for the abdominal mass and pulmonary nodules was completed. She had undergone bariatric surgery with cholecystectomy approximately 5 years earlier, after which she experienced intentional postsurgical weight loss.

Immunoglobulin(Ig)G4-related disease (IgG4-RD) is a fibroinflammatory condition that can affect virtually any organ and usually presents as tumefactive lesions involving multiple sites. Characteristic histopathology of IgG4-RD consists of dense lymphoplasmacytic infiltrate, fibrosis (often in storiform pattern), and obliterative phlebitis, accompanied by tissue infiltration of IgG4-positive plasma cells with or without elevation of serum IgG4 level. Despite a general similarity in the morphologic manifestations of IgG4-RD, site-specific unique morphologic features have been described in some organs including the lung. Compared with other sites, pulmonary involvement by IgG4-RD has been recognized more recently, and lung biopsy interpretation for this condition is often challenging, as both a relative paucity of pathognomonic features and a plethora of overlapping findings with other fibroinflammatory processes of the lung. This review is focused on the morphologic spectrum of IgG4-related lung disease documented in the current literature and on the pertinent issues in the differential diagnoses with other conditions encountered in the lung.

The diagnostic criteria of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) are not well defined, and DIPNECH can be mistaken for carcinoids associated with neuroendocrine cell hyperplasia (NECH). In this study, we compared clinical, radiologic, histologic, immunohistochemical, and molecular features of DIPNECH and isolated carcinoids with/without NECH. The study population included 151 cases (77 female patients and 74 male patients), 19 with DIPNECH and 132 with carcinoids with/without NECH. None of the cases displayed molecular alterations or anaplastic lymphoma kinase expression. Compared with individuals with carcinoids with/without NECH, patients with DIPNECH were more likely to be female individuals (P<0.0001), nonsmokers (P=0.021), and symptomatic, and to have an obstructive/mixed respiratory defect, peripheral location of the lesions, and air trapping (P<0.0001) on chest computed tomography, and constrictive bronchiolitis on histology (P<0.0001). Among immunohistochemical markers, DIPNECH was associated with higher expression of thyroid transcription factor-1, CD10, and gastrin-releasing peptide/bombesin-like peptide (P<0.0001). Yet, when a purely histopathologic definition of DIPNECH was applied, 40% of isolated carcinoids also met the diagnostic criteria for DIPNECH, even in the absence of symptoms and/or radiologic abnormalities. Therefore, as DIPNECH represents a distinct clinical syndrome, we suggest the term DIPNECH be limited to cases presenting with respiratory symptoms, functional and/or radiologic abnormalities, and constrictive bronchiolitis on histology.

This Review provides an updated approach to the diagnosis of idiopathic pulmonary fibrosis (IPF), based on a systematic search of the medical literature and the expert opinion of members of the Fleischner Society. A checklist is provided for the clinical evaluation of patients with suspected usual interstitial pneumonia (UIP). The role of CT is expanded to permit diagnosis of IPF without surgical lung biopsy in select cases when CT shows a probable UIP pattern. Additional investigations, including surgical lung biopsy, should be considered in patients with either clinical or CT findings that are indeterminate for IPF. A multidisciplinary approach is particularly important when deciding to perform additional diagnostic assessments, integrating biopsy results with clinical and CT features, and establishing a working diagnosis of IPF if lung tissue is not available. A working diagnosis of IPF should be reviewed at regular intervals since the diagnosis might change. Criteria are presented to establish confident and working diagnoses of IPF.

Pulmonary cysts are commonly identified on imaging studies and frequently pose diagnostic problems in practice. For some patients, the imaging appearances are sufficiently characteristic to allow a confident diagnosis radiologically, whereas other patients may require surgical lung biopsy to identify the etiology of the cysts. For some cystic lung diseases, the histopathology is specific, and a diagnosis can be established either by pure morphology or with the aid of ancillary testing. Other cases require more thorough clinical, radiological, and pathologic evaluation for diagnosis. This article details the clinical presentation, imaging, and pathology findings of the 5 major diffuse cystic lung diseases in adults: lymphangioleiomyomatosis, pulmonary Langerhans cell histiocytosis, lymphoid interstitial pneumonia, Birt-Hogg-Dubé syndrome, and the cysts of honeycomb remodeling. More esoteric causes of pulmonary cysts are also reviewed. A surgical pathology-based approach to cystic lung disease is provided to aid the surgical pathologist in developing a differential diagnosis that can be further narrowed by incorporating imaging and clinical features.

Coccidioidesis a virulent dimorphic fungus that causes coccidioidomycosis (valley fever) in mammals, including humans. Although the genome has been sequenced, a proteomic analysis does not exist. To address this gap in proteomic knowledge, we generated the proteome of spherulin (a well-studied lysate of fungal spherules) and identified 1390 proteins. Some of the proteins included glycosylation enzymes, which led us to hypothesize that fungal glycosylation patterns may be different from those of mammals and could be exploited to detect Coccidioidesin tissues. We performed lectin-based immunohistochemistry on formalin-fixed paraffin-embedded human patients’ lung tissues. GSL-II (Griffonia simplificonialectin II) and sWGA (succinylated wheat germ agglutinin) lectins bound specifically to endospores and spherules in infected lungs. To identify lectin-binding glycoproteins in spherulin, we performed lectin-affinity chromatography, followed by LC–MS/MS. A total of 195 glycoproteins from spherulin bound to GSL-II, 224 glycoproteins bound to sWGA, and 145 glycoproteins bound to both lectins. This is the first report of the specific reactivity of GSL-II and sWGA lectins to Coccidioidesendospores and spherules in infected human tissues and the first listing of the Coccidioidal proteome from spherulin using sequences present in three Coccidioidesdatabases: RefSeq, SwissProt, and The Broad Institute’s CoccidioidesGenome project.

The National Heart, Lung, and Blood Institute-sponsored IPF Clinical Research Network (IPFnet) studies enrolled subjects with idiopathic pulmonary fibrosis (IPF) to evaluate drug therapies in treatment trials. An adjudication committee (AC) provided a structured review of cases in which there was uncertainty or disagreement regarding diagnosis or clinical event classification. This article describes the diagnosis and adjudication processes.

Integration of visual characterization of emphysema and airway abnormalities with physiologic and quantitative CT assessment permits categorization of chronic obstructive pulmonary disease into distinct structurally and functionally defined subtypes.

Idiopathic pulmonary fibrosis is a progressive fibrotic lung disease that distorts pulmonary architecture, leading to hypoxia, respiratory failure, and death. Diagnosis is difficult because other interstitial lung diseases have similar radiological and histopathological characteristics. A usual interstitial pneumonia pattern is a hallmark of idiopathic pulmonary fibrosis and is essential for its diagnosis. We aimed to develop a molecular test that distinguishes usual interstitial pneumonia from other interstitial lung diseases in surgical lung biopsy samples. The eventual goal of this research is to develop a method to diagnose idiopathic pulmonary fibrosis without the patient having to undergo surgery.

Undifferentiated connective tissue disease (UCTD) involves conditions characterized by both having symptoms of connective tissue disease (CTD) and autoantibodies but not fulfilling the criteria of a specific CTD. The frequency or prognosis of the usual interstitial pneumonia (UIP) pattern in UCTD is unknown, which may be confused with idiopathic pulmonary fibrosis (IPF). This study aimed to investigate the frequency of the UIP pattern in interstitial pneumonia related to UCTD and compare its prognosis with that of IPF and UCTD-nonspecific interstitial pneumonia (UCTD-NSIP).

Two cases of diffuse dendriform pulmonary ossification (DPO) are presented, one of the secondary type and the other of the idiopathic type. Case 1 was an adult female patient who underwent thoracic surgery to remove a posterior mediastinal bronchogenic cyst, which was discovered on a computed tomography scan performed after an episode of pneumonia when traction bronchiectasis with interstitial lung disease/fibrosis was also suspected in the lungs. Histologic examination performed on the resected lung tissue revealed numerous scattered small osseous spicules on a background of intense interstitial inflammation and fibrosis, leading to further clinical and laboratory investigations and the final diagnosis of DPO secondary to lung involvement by scleroderma. Case 2 was an adult male patient who underwent thoracoscopic exploration after a computed tomography scan, which revealed traction bronchiectasis with linear thickening of the interstitial lung tissue. Histologic examination of the lung tissue specimen revealed numerous osseous spicules in the absence of interstitial septal inflammation. Noteworthy in this case were also some nodules of collagenized tissue similar to those seen in the lungs of patients affected by Ehlers-Danlos syndrome. The absence of any clinical sign or symptoms related to Ehlers-Danlos syndrome attest to the nonspecificity of these pulmonary fibrous nodules. No case of DPO secondary to scleroderma has been reported in the literature so far, although around half of the patients with scleroderma manifest pulmonary diseases. Idiopathic DPO is even rarer, usually discovered postmortem, with only 20 cases diagnosed in life with lung biopsies taken by open surgery or through a thoracoscopic approach. DPO is often misdiagnosed radiologically as bronchiectasis and/or interstitial lung disease/fibrosis.

Skeletal coccidioidomycosis is a rare complication of pulmonary coccidioidomycosis that remains incompletely characterized, and its histopathologic features have not been systematically evaluated. All skeletal coccidioidal infections (2000 to 2012) were retrieved from the University of Arizona and Mayo Clinic in Arizona pathology archives. Clinical history and histologic features were reviewed. Among 25 patients (median age 40 y; 17 men), infections involved bones (2 cases), joints (6), or both (17), usually in the distal extremities (68%), especially the wrist (32%). History included previously documented coccidioidomycosis (13), autoimmune disease (8), diabetes (6), malignancy (4), and iatrogenic immunosuppression (10). Common symptoms (median 3 mo) included pain/arthralgia (21) and swelling (10). Cultures and serology were positive in 15 of 17 (88%) and 19 of 22 patients (86%), respectively. Treatment included surgical debridement(s) and chronic antifungal medication(s). Histologic review showed granulomas in all cases, ranging from poorly to well formed, with or without necrosis. Spherule density varied widely (mean 4.8/HPF; range <0.1 to 13.5/HPF). Composition of inflammatory infiltrates, degree of necrosis, and extent of fibrosis did not significantly differ between immunocompetent and immunocompromised patients. Eosinophils were only seen in one third of cases; when present, eosinophils were almost always rare. 10 patients experienced recurrent infection, 8 of whom were immunocompromised; the remaining patients recovered. In conclusion, distal extremities are the most common sites of skeletal coccidioidomycosis encountered by surgical pathologists. This condition is strongly associated with autoimmune disorders and immunosuppression. Spherules are sometimes rare, and multiple modalities including serology, culture, and histology may be required for diagnosis.

Pulmonary mucoepidermoid carcinoma is an uncommon but distinctive manifestation of mucoepidermoid carcinoma. Pulmonary mucoepidermoid carcinoma occurs in adults and children and can cause diagnostic problems, especially in small biopsies. Few studies have characterized the histologic and immunophenotypic features of pulmonary mucoepidermoid carcinoma. t(11;19)(q21;p13) is considered disease-defining for mucoepidermoid carcinoma; its significance in pulmonary mucoepidermoid carcinoma warrants further study. Forty three pulmonary mucoepidermoid carcinomas were re-reviewed and graded according to the Brandwein grading system for mucoepidermoid carcinoma. Four cases were excluded because of a split opinion between pathology report and re-review. These cases were negative for MAML2 rearrangement by FISH. TTF-1, napsin A, p40 and p63 immunostains were scored: 0 (negative), 1 (1–25% tumor cells), 2 (26–50%), 3 (51–75%) or 4 (>75%). FISH to detect MAML2 rearrangement used a MAML2-11q21 break-apart probe. Thirty nine pulmonary mucoepidermoid carcinoma (4 low, 30 intermediate, 5 high grade) contained mucous, epidermoid and intermediate cells and lacked keratinization and in situ carcinoma of the overlying epithelium. All cases with available gross description (n=22) had a central/endo- or peribronchial location. All 25 cases tested for immunohistochemistry were positive (scores 1–4) for p63; 23 also expressed p40. In six cases, the p63 score was higher than p40. TTF-1 and napsin were uniformly negative in all 25 cases. MAML2 rearrangement was identified by FISH in each of the 24 cases tested (3 low, 19 intermediate, 2 high grade). Clinical history was available in 29 patients (15 men) (median age, 48 years) with follow-up in 24 (median, 8.4 years). Five patients died of unrelated causes; one developed metastatic pulmonary mucoepidermoid carcinoma. In conclusion, features helpful in distinguishing pulmonary mucoepidermoid carcinoma from other lung cancers include its central/endo- or peribronchial location together with the presence of mucous cells, p63 expression, lack of keratinization and MAML2 rearrangement. TTF-1 and napsin are typically not expressed.

Pulmonary mucoepidermoid carcinoma is an uncommon but distinctive manifestation of mucoepidermoid carcinoma. Pulmonary mucoepidermoid carcinoma occurs in adults and children and can cause diagnostic problems, especially in small biopsies. Few studies have characterized the histologic and immunophenotypic features of pulmonary mucoepidermoid carcinoma. t(11;19)(q21;p13) is considered disease-defining for mucoepidermoid carcinoma; its significance in pulmonary mucoepidermoid carcinoma warrants further study. Forty three pulmonary mucoepidermoid carcinomas were re-reviewed and graded according to the Brandwein grading system for mucoepidermoid carcinoma. Four cases were excluded because of a split opinion between pathology report and re-review. These cases were negative for MAML2rearrangement by FISH. TTF-1, napsin A, p40 and p63 immunostains were scored: 0 (negative), 1 (1–25% tumor cells), 2 (26–50%), 3 (51–75%) or 4 (>75%). FISH to detect MAML2rearrangement used a MAML2-11q21 break-apart probe. Thirty nine pulmonary mucoepidermoid carcinoma (4 low, 30 intermediate, 5 high grade) contained mucous, epidermoid and intermediate cells and lacked keratinization and in situcarcinoma of the overlying epithelium. All cases with available gross description (n=22) had a central/endo- or peribronchial location. All 25 cases tested for immunohistochemistry were positive (scores 1–4) for p63; 23 also expressed p40. In six cases, the p63 score was higher than p40. TTF-1 and napsin were uniformly negative in all 25 cases. MAML2rearrangement was identified by FISH in each of the 24 cases tested (3 low, 19 intermediate, 2 high grade). Clinical history was available in 29 patients (15 men) (median age, 48 years) with follow-up in 24 (median, 8.4 years). Five patients died of unrelated causes; one developed metastatic pulmonary mucoepidermoid carcinoma. In conclusion, features helpful in distinguishing pulmonary mucoepidermoid carcinoma from other lung cancers include its central/endo- or peribronchial location together with the presence of mucous cells, p63 expression, lack of keratinization and MAML2rearrangement. TTF-1 and napsin are typically not expressed.

Plants produce hundreds of glycosidases. Despite their importance in cell wall (re)modeling, protein and lipid modification, and metabolite conversion, very little is known of this large class of glycolytic enzymes, partly because of their post-translational regulation and their elusive substrates. Here, we applied activity-based glycosidase profiling using cell-permeable small molecular probes that react covalently with the active site nucleophile of retaining glycosidases in an activity-dependent manner. Using mass spectrometry we detected the active state of dozens of myrosinases, glucosidases, xylosidases, and galactosidases representing seven different retaining glycosidase families. The method is simple and applicable for different organs and different plant species, in living cells and in subproteomes. We display the active state of previously uncharacterized glycosidases, one of which was encoded by a previously declared pseudogene. Interestingly, glycosidase activity profiling also revealed the active state of a diverse range of putative xylosidases, galactosidases, glucanases, and heparanase in the cell wall of Nicotiana benthamiana. Our data illustrate that this powerful approach displays a new and important layer of functional proteomic information on the active state of glycosidases.