Colby, Thomas V.

Abstract Rationale Surgical lung biopsy is often required for a confident multidisciplinary diagnosis of idiopathic pulmonary fibrosis (IPF). Alternative, less-invasive biopsy methods, such as bronchoscopic lung cryobiopsy (BLC), are highly desirable. Objectives To address the impact of BLC on diagnostic confidence in the multidisciplinary diagnosis of IPF. Methods In this cross-sectional study we selected 117 patients with fibrotic interstitial lung disease without a typical usual interstitial pneumonia pattern on high-resolution computed tomography. All cases underwent lung biopsies: 58 were BLC, and 59 were surgical lung biopsy (SLB). Two clinicians, two radiologists, and two pathologists sequentially reviewed clinical-radiologic findings and biopsy results, recording at each step in the process their diagnostic impressions and confidence levels. Measurements and Main Results We observed a major increase in diagnostic confidence after the addition of BLC, similar to SLB (from 29 to 63%, P = 0.0003 and from 30 to 65%, P = 0.0016 of high confidence IPF diagnosis, in the BLC group and SLB group, respectively). The overall interobserver agreement in IPF diagnosis was similar for both approaches (BLC overall kappa, 0.96; SLB overall kappa, 0.93). IPF was the most frequent diagnosis (50 and 39% in the BLC and SLB group, respectively; P = 0.23). After the addition of histopathologic information, 17% of cases in the BLC group and 19% of cases in the SLB group, mostly idiopathic nonspecific interstitial pneumonia and hypersensitivity pneumonitis, were reclassified as IPF. Conclusions BLC is a new biopsy method that has a meaningful impact on diagnostic confidence in the multidisciplinary diagnosis of interstitial lung disease and may prove useful in the diagnosis of IPF. This study provides a robust rationale for future studies investigating the diagnostic accuracy of BLC compared with SLB.

Intravesical instillation of Bacillus Calmette-Guérin (BCG) is a mainstay of adjunctive therapy for superficial bladder cancer. Disseminated BCG infection (“BCG-osis”) after this therapy is rare and potentially life-threatening; only isolated case reports detail the histopathologic findings thereof, few of which had a diagnosis confirmed by molecular testing. We report 3 additional cases of BCG-osis complicating BCG therapy, all confirmed by cultures and molecular assays, including the first cases of wedge biopsy-confirmed BCG pneumonia and BCG olecranon bursitis. When suggested by a relevant clinical history, recognition of randomly distributed granulomas in any organ should prompt consideration of BCG-osis and liberal performance of AFB stains, aided by targeted molecular assays. Physicians should maintain a high index of suspicion when miliary infiltrates arise after intravesical BCG instillation, and close multidisciplinary communication is essential. Pathologist awareness of this rare cause of granulomatous inflammation aids recognition of BCG-osis and facilitates prompt initiation of antimycobacterial therapy.

AbstractPyoderma gangrenosum is a chronic sterile skin disorder that is frequently seen in association with systemic disorders such as inflammatory bowel disease. Extracutaneous pyoderma gangrenosum is rare and most commonly occurs in the lungs. It is particularly unusual for extracutaneous pyoderma gangrenosum to manifest prior to skin findings and without an associated systemic disorder. A 19‐year‐old white man presented with shortness of breath and a productive cough. His skin exam was normal. Unenhanced chest computed tomography showed peripheral consolidations, areas of cavitation, nodules and bilateral pleural effusions. A bronchoalveolar lavage and an autoimmune panel were unremarkable. Right lung wedge biopsies via thoracostomy was performed and showed pulmonary pyoderma gangrenosum. He was treated with corticosteroids and has returned back to his baseline. This is the first case of pulmonary pyoderma gangrenosum without any associated underlying systemic disorder and without any cutaneous manifestations to date. Serial follow‐ups are necessary to assess for the development of an associated systemic disorder or skin lesions.

Abstract Erdheim-Chester disease (ECD) is a rare, non-Langerhans histiocytosis. Recent findings suggest that ECD is a clonal disorder, marked by recurrent BRAFV600E mutations in >50% of patients, in which chronic uncontrolled inflammation is an important mediator of disease pathogenesis. Although ∼500 to 550 cases have been described in the literature to date, increased physician awareness has driven a dramatic increase in ECD diagnoses over the last decade. ECD frequently involves multiple organ systems and has historically lacked effective therapies. Given the protean clinical manifestations and the lack of a consensus-derived approach for the management of ECD, we provide here the first multidisciplinary consensus guidelines for the clinical management of ECD. These recommendations were outlined at the First International Medical Symposium for ECD, comprised of a comprehensive group of international academicians with expertise in the pathophysiology and therapy of ECD. Detailed recommendations on the initial clinical, laboratory, and radiographic assessment of ECD patients are presented in addition to treatment recommendations based on critical appraisal of the literature and clinical experience. These formalized consensus descriptions will hopefully facilitate ongoing and future research efforts in this disorder.

ObjectiveIgG4‐related disease (IgG4RD) causing sinonasal and skull base pathology is uncommonly described. We present a series of suspected IgG4RD patients, with a pertinent review of the literature to highlight diagnostic challenges.Study DesignCase series.SettingAcademic tertiary care center.Subjects and MethodsCase series of patients with IgG4RD or suspected IgG4RD involving the sinonasal cavity and skull base.ResultsWe present 4 patients with atypical sinonasal and/or skull base disease who were noted to have IgG4‐positive plasma cell infiltration on immunohistochemistry of biopsy specimens. IgG4RD, a recently described entity affecting multiple organs, is characterized by lymphoplasmacytic infiltration and often elevated serum IgG4. IgG4RD can masquerade as malignancy or infection but responds to glucocorticosteroid and immunosuppressant therapy. IgG4RD has been infrequently reported presenting as sinonasal or skull base lesions, and definitive diagnostic criteria for these regions are not established. In our series, IgG4RD was suspected in all 4 patients, but only 1 met all current criteria for definitive diagnosis. All 4 patients, however, responded to corticosteroid therapy, and 1 was placed on long‐term azathioprine.ConclusionIgG4RD is rarely described in the sinonasal cavity and skull base, and specific diagnostic criteria for such disease have not been defined. We present a series of patients with IgG4‐positive plasma cell inflammatory pathology who were suspected to have IgG4RD. Our series highlights diagnostic challenges associated with these patients. Tumefactive and destructive sinonasal‐skull base lesions with a plasma cell‐rich infiltrate should incite suspicion of IgG4RD, and immunohistochemistry for IgG4‐positive plasma cells should be performed.

Abstract Mouse models of allergen provocation and/or transgenic gene expression have provided significant insights regarding the cellular, molecular, and immune responses linked to the pathologies occurring as a result of allergic respiratory inflammation. Nonetheless, the inability to replicate the eosinophil activities occurring in patients with asthma has limited their usefulness to understand the larger role(s) of eosinophils in disease pathologies. These limitations have led us to develop an allergen-naive double transgenic mouse model that expresses IL-5 systemically from mature T cells and eotaxin-2 locally from lung epithelial cells. We show that these mice develop several pulmonary pathologies representative of severe asthma, including structural remodeling events such as epithelial desquamation and mucus hypersecretion leading to airway obstruction, subepithelial fibrosis, airway smooth muscle hyperplasia, and pathophysiological changes exemplified by exacerbated methacholine-induced airway hyperresponsiveness. More importantly, and similar to human patients, the pulmonary pathologies observed are accompanied by extensive eosinophil degranulation. Genetic ablation of all eosinophils from this double transgenic model abolished the induced pulmonary pathologies, demonstrating that these pathologies are a consequence of one or more eosinophil effector functions.

The histologic characteristics of air space enlargement with fibrosis (AEF) are compared with usual interstitial pneumonia (UIP), nonspecific interstitial pneumonia (NSIP) and centrilobular emphysema (CLE) to determine similarities and differences. Lung specimens from 39 patients were studied; 9 with AEF, 13 with UIP and 5 with CLE identified in lobectomy specimens for cancer and 12 NSIP cases identified on surgical lung biopsies. We determined the characteristics of cystic structures (i.e. abnormal airspace), degree of inflammation and severity of pneumocyte injury semi‐quantitatively. In AEF, the wall thickness of the cystic lesions (0.8 mm) was thinner than in UIP (2.1 mm) and thicker than in CLE (0.07 mm). The degree of inflammation and granulation tissue were milder in AEF than in UIP and NSIP and CLE showed milder inflammatory cells than AEF. As for pneumocyte injury, AEF had fewer erosions (0.1/case) and fewer ubiquitin‐positive pneumocytes than UIP (4.8 cells/slide) and NSIP (9.8 cells/slide). Our data suggested that the histological characteristics of AEF differed significantly from UIP, NSIP and CLE.