Yi, Eunhee S.

Abstract Context. —Not uncommonly, a surgical pathologist will be requested to review excised material, with a clinical diagnosis of cancer, in which no malignancy can be identified. Often, sampling may be the issue. However, different nonneoplastic processes may mimic cancer clinically and not be recognized histologically. These are commonly referred to as pseudoneoplasms and can involve the lung, pleura, and mediastinum. Objective. —To review the most commonly encountered pseudoneoplasms of the thoracic cavity in surgical pathology and discuss the main differential diagnosis. Data Sources. —Literature and personal review of cases with focus on inflammatory pseudotumors of the lung, organizing pneumonia, nodular lymphoid hyperplasia, apical cap, round atelectasis, and sclerosing mediastinitis with its pulmonary counterpart, hyalinizing granuloma. Conclusions. —When reviewing specimens that appear nondiagnostic for malignancy, it is important to consider one of these pseudoneoplasms in the differential diagnosis as they may explain the clinical and radiologic information.

Loss of BMP (bone morphogenic protein) signaling induces a phenotype switch of pulmonary arterial smooth muscle cells (PASMCs), which is the pathological basis of pulmonary vascular remodeling in pulmonary arterial hypertension (PAH). Here, we identified FGF12 (fibroblast growth factor 12) as a novel regulator of the BMP-induced phenotype change in PASMCs and elucidated its role in pulmonary vascular remodeling during PAH development. Using murine models of PAH and lung specimens of patients with PAH, we observed that FGF12 expression was significantly reduced in PASMCs. In human PASMCs, FGF12 expression was increased by canonical BMP signaling. FGF12 knockdown blocked the antiproliferative and prodifferentiation effect of BMP on human PASMCs, suggesting that FGF12 is required for the BMP-mediated acquisition of the quiescent and differentiated PASMC phenotype. Mechanistically, FGF12 regulated the BMP-induced phenotype change by inducing MEF2a (myocyte enhancer factor 2a) phosphorylation via p38MAPK signaling, thereby modulating the expression of MEF2a target genes involved in cell proliferation and differentiation. Furthermore, we observed that TG (transgenic) mice with smooth muscle cell–specific FGF12 overexpression were protected from chronic hypoxia–induced PAH development, pulmonary vascular remodeling, and right ventricular hypertrophy. Consistent with the in vitro data using human PASMCs, FGF12 TG mice showed increased MEF2a phosphorylation and a substantial change in MEF2a target gene expression, compared with the WT (wild type) controls. Overall, our findings demonstrate a novel BMP/FGF12/MEF2a pathway regulating the PASMC phenotype switch and suggest FGF12 as a potential target for the development of therapeutics for ameliorating pulmonary vascular remodeling in PAH.

There are limited data regarding the surgical management of primary pulmonary artery sarcomas (PPAS) because of their rarity and complicated diagnostic history. The objective of this study was to analyze our institution’s long-term surgical management outcomes for PPAS in the absence of a care pathway. From May 1997 to June 2013, 8 patients (mean age 60.6 ± 11.8 years; range, 40-73 years; 5 women and 3 men) underwent surgical intervention for PPAS at our institution. The most common computed tomography finding was a luminal filling defect obstructing the pulmonary artery (PA), without evidence of extraluminal extension. Three patients underwent debulking/pulmonary endarterectomy alone and 5 patients underwent a more radical resection with PA patch angioplasty, PA resection and reconstruction, pulmonary valve replacement, and unilateral pneumonectomy. The mean postoperative survival in this series was 3.8 ± 3.6 years (range, 1-11.9 years), with 2 radical surgical resection patients alive at 4.9 and 11.9 years, respectively. For those patients with incomplete resection, 3-dimensional (3D) models were created to demonstrate the advantage of a preoperative guide for a more complete resection and what it would entail. Six patients had local recurrences with mean disease-free interval of 14 ± 10.9 months (range, 2 months-2.5 years), and 2 patients with re-resections had an overall postoperative survival of 2.8 and 11.9 years, respectively. In our small cohort of PPAS, patients treated with radical surgical resection had better survival. The small number of PPAS cases in this series makes proving this association unlikely but warrants consideration.

Context.— Idiopathic pulmonary fibrosis is a clinical syndrome characterized by the presence of usual interstitial pneumonia (UIP) radiologically and pathologically. Per consensus criteria adopted in 2011, diagnosis of idiopathic pulmonary fibrosis no longer requires a biopsy in an appropriate context if UIP is seen on imaging. As a result, lung biopsies are now typically reserved for patients having indeterminate clinical or imaging findings or suspicion for alternative diagnoses, but the impact of updated guidelines on pathology practice remains unclear. Objective.— To determine the frequency of histologic UIP before and after 2011. Design.— Surgical lung biopsies from adults were studied within two 4-year periods: July 1, 2006 through June 30, 2010 and January 1, 2012 through December 31, 2015. Pathology slides were reviewed in a fashion blinded to clinical information and were classified using current guidelines. Results.— Biopsies from 177 and 86 patients (mean [SD] age, 62 [12] and 59 [14] years; 50.3% [89 of 177] and 48.8% [42 of 86] men) before and after 2011, respectively, were reviewed. Probable UIP or UIP was less-frequently encountered after 2011 in all patients with fibrosis (9 of 54 [16.7%] versus 41 of 119 [34.5%] before 2011, P = .02) and also in patients 50 years old and older (8 of 46 [17.4%] versus 39 of 109 [35.8%] before 2011, P = .02), with a concomitant rise in cases indeterminate for UIP or showing alternative diagnoses. Conclusions.— Histology for UIP is less frequently encountered in our contemporary practice compared with the historic era. The pretest probability of a non-UIP diagnosis is now high, even in elderly patients, underscoring the need for pathologists to be familiar with the histologic features of alternative diagnoses.

Common variable immunodeficiency (CVID) and selective immunoglobulin A deficiency (IgAD) often cause chronic lung disease, but the pulmonary pathologic features of these systemic diseases are poorly recognized by pathologists. It has been claimed that CVID cases show a characteristic combination of noncaseating granulomas-lymphoid proliferations termed granulomatous-lymphocytic interstitial lung disease (GLILD). We present 34 surgical lung biopsy cases of CVID and 4 of IgAD. Noncaseating granulomas were seen in 23/34 (68%) CVID and 2/4 (50%) IgAD cases. A statistically identical pattern of benign lymphoid proliferation was found in CVID and IgAD whether or not granulomas were present. Organizing pneumonia, sometimes considered a part of GLILD, was seen in 25/34 (74%) CVID and 2/4 (50%) IgAD cases and did not correlate with the presence of granulomas. On follow-up, 3 CVID patients died (only 1 of pulmonary disease), while 21 others are alive at 1 to 300 months with no difference by presence or absence of granulomas. Three IgAD patients with follow-up are alive. We conclude that CVID and IgAD are indistinguishable in surgical lung biopsies and a subset of both show patterns that would qualify as GLILD, while other cases lack granulomas but have identical patterns of lymphoid infiltration and organizing pneumonia. We suggest that GLILD is neither a specific nor a useful entity, and biopsies from CVID and IgAD patients should be diagnosed simply by microscopic pattern(s) observed. The prognosis of CVID with lymphoid infiltrates with or without granulomas in this series was good, contrary to claims in the literature about GLILD.

11119 Background: Evaluation of prognostic factors in carcinoid tumors of the lung is limited due to the rarity of disease. This study assessed Ki-67 expression and other clinical variables as prognostic factors in 262 patients. Methods: A systematic search of Mayo Clinic lung cancer epidemiology and tumor registry databases from 1997 to 2009 identified 449 consecutive patients, with 262 having available tissue blocks [40 atypical carcinoids (AC) and 222 typical carcinoids (TC)]. Clinical data were collected by chart review. Tissue blocks were reviewed by 1/3 pathologists using WHO criteria. Tumors were tested for the Ki-67 index using digital image analysis (tumor tracing) by two operators. The association and predictive value of the factors with recurrence-free and overall survival (RFS and OS) were explored using univariable Cox proportional Hazards model and concordance (c) index. Results: Age, stage, smoking history, lymph node (LN) involvement and Ki-67 index were significant prognostic factors for RFS and OS. Median follow-up on alive-patients is 5 years (range: 0.006-5). Median percentage of Ki-67 index of AC and TC were 1.61% and 0.56% (P<0.0001), respectively. Patients with Ki-67 ≥ 1% had significantly worse RFS (HR=3.69, P<0.0001) and OS (HR=3.69, P=0.0007) compared with Ki-67 < 1% group. The c-index of Ki-67 (0.65) was comparable to the pathologic distinction between AC and TC (0.62 for original diagnosis and 0.63 for central-reviewed diagnosis). Conclusions: Ki-67 index cutoff value of 1% is a valuable prognostic biomarker for pulmonary carcinoids based on this large cohort. Our data also provide strong evidence for clinical variables such as age, stage, smoking history, and LN involvement as clinical prognostic factors in pulmonary carcinoids. A prognostic calculator incorporating Ki-67 and clinical variables is under development. [Table: see text]

e21039 Background: Tumor-infiltrating neutrophils (TINs) and their myeloid precursors play an important role in cancer biology. While activated neutrophils have been shown to kill tumor cells, there is growing evidence that neutrophils may also support tumor progression by impairing T cell-dependent anti-tumor immunity. We hypothesized that low TINs would be associated with better responses to immunotherapy (IO). Methods: Pretreatment biopsies from 15 metastatic melanoma (MM) pts treated with anti-CTL4 and anti-PD-1 therapy from 2012-17 were collected and stained with myeloperoxidase (MPO). Slides were scanned at 40x magnification on the Aperio ScanScope AT Turbo brightfield instrument (Leica Biosystems) at a resolution of 0.25 microns per pixel. To indicate the region of analysis, the digital pen tool was used to trace a minimum 85% of tumor. Ten fixed-sized boxes were placed on the hottest staining region in a second annotation layer on the image. The boxes equaled 1mm2 in total area. If the tumor tracing had an area of 1mm2, or less, boxes were not placed on the image. The selected tissue was analyzed using an Aperio imaging quatification algorithm . The number of 3+ cells were considered positive for neutrophils and used in subsequent calculations. Quality control review was performed on a subset of cases by Anatomic Pathologists. Response to therapy was assessed using the Response Evaluation Criteria In Solid Tumors (RECIST). Overall survival (OS) was calculated using the Kaplan Meier method. Results: The median number of treatment lines before the biopsy was 1 (range 0-2). The treatment immediately following the biopsy consisted of ipilimumab (n = 10, 66.6%), pembrolizumab (n = 4, 26.6%), ipilimumab/nivolumab (n = 1, 6.6%). The median number of neutrophils in the biopsy hotspot was 92/mm2 (range 6-219) for the entire cohort. For patients achieving PR and CR after 4 cycles of therapy, the median neutrophils were 36/mm2 (IQ 14-78) while the median was 106/mm2 (IQ 60-138) for patients who had progressive disease,( p = 0.04). There was no correlation between the numbers of neutrophils in the biopsy with the absolute neutrophil count in the peripheral blood (R value: 0.012). Conclusions: Decreased TINs are significantly associated with better responses to IO in MM pts. Measurements of TINs may help to select patients who are likely to benefit from anti-CTL4 and anti-PD-1 therapy. Additionally, exploration of whether combining therapies that decrease neutrophils intratumorally should be explored.