Tissue-location-specific transcription programs drive tumor dependencies in colon cancer.

Cancers of the same tissue-type but in anatomically distinct locations exhibit different molecular dependencies for tumorigenesis. Proximal and distal colon cancers exemplify such characteristics, with BRAFV600E predominantly occurring in proximal colon cancers along with increased DNA methylation phenotype. Using mouse colon organoids, here we show that proximal and distal colon stem cells have distinct transcriptional programs that regulate stemness and differentiation. We identify that the homeobox transcription factor, CDX2, which is silenced by DNA methylation in proximal colon cancers, is a key mediator of the differential transcriptional programs. Cdx2-mediated proximal colon-specific transcriptional program concurrently is tumor suppressive, and Cdx2 loss sufficiently creates permissive state for BRAFV600E-driven transformation. Human proximal colon cancers with CDX2 downregulation showed similar transcriptional program as in mouse proximal organoids with Cdx2 loss. Developmental transcription factors, such as CDX2, are thus critical in maintaining tissue-location specific transcriptional programs that create tissue-type origin specific dependencies for tumor development.

Aberrant p53 Expression in Gastric Biopsies and Resection Specimens Following Neoadjuvant Chemoradiation: A Diagnostic Pitfall.

Gastric mucosal biopsies and resections from patients treated with neoadjuvant radiation and/or chemotherapy are frequently encountered. These samples may show histologic features related to therapy including inflammation, ulceration, and epithelial atypia. In some cases, epithelial atypia may be marked, prompting the use of adjunct p53 immunohistochemistry. We examined p53 expression by immunohistochemistry in gastric mucosa following therapy.We evaluated the histology and p53 immunohistochemical expression in gastric mucosa from 57 resections and 3 mucosal biopsies, from 60 patients treated with radiation and/or chemotherapy for gastroesophageal carcinoma (n = 33) or pancreatic carcinoma (n = 27).We identified histomorphologic features of therapy-related epithelial changes in 50 of 60 cases (83%). Abnormal p53 expression was present at least focally in nearly half the cases (27 of 60 cases; 45%), all of which showed morphologic evidence of therapy-related epithelial changes. Neuroendocrine cell micronests were present in 37 of 60 cases (62%). Next-generation sequencing (NGS) of foci with therapy-related epithelial changes showing abnormal p53 expression and carcinoma from the same patient was attempted and yielded results in 1 patient. Interestingly, differing TP53 alterations in the patient's adenocarcinoma and in a histologically benign esophageal submucosal gland with therapy-related epithelial changes and abnormal p53 expression were identified.Our results demonstrate that abnormal p53 expression is relatively common in gastric mucosal samples following radiation and/or chemotherapy and suggest that p53 expression should be avoided when distinguishing therapy-related changes from dysplasia or carcinoma. Furthermore, our NGS results raise interesting biological questions, which may warrant further investigation.

A nanofiber-hydrogel composite improves tissue repair in a rat model of Crohn's disease perianal fistulas.

Perianal fistulas (PAFs) represent a severe complication of Crohn's disease (CD). Despite the advent of biologic and small-molecule therapeutics for luminal disease, PAFs in CD (CD-PAF) are relatively resistant to treatment, with less than 50% responding to any therapy. We report an injectable, biodegradable, mechanically fragmented nanofiber-hydrogel composite (mfNHC) loaded with adipose-derived stem cells (ADSCs) for the treatment of fistulas in a rat model of CD-PAF. The ADSC-loaded mfNHC results in a higher degree of healing when compared to surgical treatment of fistulas, which is a standard treatment. The volume of fistulas treated with mfNHC is decreased sixfold compared to the surgical treatment control. Molecular studies reveal that utilization of mfNHC reduced local inflammation and improved tissue regeneration. This study demonstrates that ADSC-loaded mfNHC is a promising therapy for CD-PAF, and warrants further studies to advance mfNHC toward clinical translation.

Injectable, Drug-Eluting Nanocrystals Prevent Fibrosis and Stricture Formation In Vivo.

BACKGROUND & AIMS: Tissue fibrosis results from uncontrolled healing responses leading to excessive mesenchymal cell activation and collagen and other extracellular matrix deposition. In the gastrointestinal tract, fibrosis leads to narrowing of the lumen and stricture formation. A drug treatment to prevent fibrosis and strictures in the gastrointestinal tract would be transformational for patient care. We aimed to develop a stricture treatment with the following characteristics and components: a small molecule with strong antifibrotic effects that is delivered locally at the site of the stricture to ensure correct lesional targeting while protecting the systemic circulation, and that is formulated with sustained-release properties to act throughout the wound healing processes. METHODS: A high-throughput drug screening was performed to identify small molecules with antifibrotic properties. Next, we formulated an antifibrotic small molecule for sustained release and tested its antifibrotic potential in 3 animal models of fibrosis. RESULTS: Sulconazole, a US Food and Drug Administration-approved drug for fungal infections, was found to have strong antifibrotic properties. Sulconazole was formulated as sulconazole nanocrystals for sustained release. We found that sulconazole nanocrystals provided superior or equivalent fibrosis prevention with less frequent dosing in mouse models of skin and intestinal tissue fibrosis. In a patient-like swine model of bowel stricture, a single injection of sulconazole nanocrystals prevented stricture formation. CONCLUSIONS: The current data lay the foundation for further studies to improve the management of a range of diseases and conditions characterized by tissue fibrosis.

Web-based pathology modules with virtual slides are effective for teaching introductory gastrointestinal pathology concepts.

Pathology interns face a steep learning curve as they transition from medical school to residency. Innovative teaching tools are needed to effectively and efficiently bridge this gap. We created four online learning modules geared toward pathology interns, for use at the beginning of the gastrointestinal pathology rotation at our institution. Our modules covered introductory esophageal, gastric, small bowel, and colonic pathology. Each module incorporated photomicrographs and annotated virtual slides, and included pre- and post-module assessment questions and a link to an anonymous survey. Twelve interns completed the modules between 9/20/2019 and 12/31/2021, including 80% of the 2020-2021 intern class. Significant improvement in performance was seen between the pre- and post-module questions for the stomach, small bowel, and colon modules (p < 0.05 for all), with a trend toward improved performance with the esophageal module. Interns rated the modules highly and indicated that they would recommend the modules to their peers. While the modules were geared toward interns, due to the coronavirus-19 pandemic we expanded access to the modules to include medical students. Medical students also found the learning modules valuable and requested more modules in the future. We conclude that online learning modules are an effective tool for teaching pathology interns and are well-received by this group. Online modules can also be seamlessly incorporated into asynchronous medical student teaching.

Some Morphology Frontiers of Dysplasia in the Tubular Gastrointestinal Tract: The Rodger C. Haggitt Memorial Lecture.

This review, based on the content of the 2020 US Gastrointestinal Pathology Society's Rodger Haggitt Lecture, concerns an array of tubular gastrointestinal tract dysplastic or possible "predysplastic lesions" with an almost purely morphologic focus based on our collaborative efforts over the past few years. These processes include esophageal epidermoid metaplasia, Barrett esophagus-associated dysplasia, polypoid gastric dysplastic lesions, small intestinal dysplasia, and the ability of metastases to mimic it, the controversial "serrated epithelial change" encountered in the setting of long-standing ulcerative and Crohn colitis, and recently described anal columnar human papilloma virus-associated neoplasms.

The path(ology) from reflux oesophagitis to Barrett oesophagus to oesophageal adenocarcinoma.

This review seeks to summarise the steps in the path from reflux oesophagitis to Barrett oesophagus to oesophageal adenocarcinoma. The epidemiology, clinical presentation, definitions, pathological features, diagnostic pitfalls, and emerging concepts are reviewed for each entity. The histological features of reflux oesophagitis can be variable and are not specific. Cases of reflux oesophagitis with numerous eosinophils are difficult to distinguish from eosinophilic oesophagitis and other oesophagitides with eosinophils (Crohn's disease, medication effect, and connective tissue disorders). In reflux oesophagitis, the findings are often most pronounced in the distal oesophagus, the eosinophils are randomly distributed throughout the epithelium, and eosinophilic abscesses and degranulated eosinophils are rare. For reflux oesophagitis with prominent lymphocytes, clinical history and ancillary clinical studies are paramount to distinguish reflux oesophagitis from other causes of lymphocytic oesophagitis pattern. For Barrett oesophagus, the definition remains a hotly debated topic for which the requirement for intestinal metaplasia to make the diagnosis is not applied unanimously across the globe. Assessing for dysplasia is a challenging aspect of the histological interpretation that guides clinical management. We describe the histological features that we find useful in making this evaluation. Oesophageal adenocarcinoma has been steadily increasing in incidence and has a poor prognosis. The extent of invasion can be overdiagnosed due to a duplicated muscularis mucosae. We also describe the technical factors that can lead to challenges in distinguishing the mucosal and deep margins of endoscopic resections. Lastly, we give an overview of targeted therapies with emerging importance and the ancillary tests that can identify the cases best suited for each therapy.

Gastric Mucosal Devitalization (GMD): Using the Porcine Model to Develop a Novel Endoscopic Bariatric Approach.

BACKGROUND AND AIMS: As the pig model has similar gastrointestinal anatomy and physiology to humans, we used pigs to create a gastric mucosal devitalization (GMD) model in preparation for clinical translation of this technique as an endoscopic bariatric therapy (EBT). The aims of this study were to determine the ablation parameters and technique for a successful, safe, and feasible large surface area GMD that produces weight loss. METHODS: We performed GMD using argon plasma coagulation (APC) in 3 phases. Phase 1 assessed the ablation energy required to accomplish selective mucosal ablation using ex vivo pig stomachs (n = 2). Phase 2 assessed the optimal percentage of mucosal surface area to be treated and was performed on 10 pigs. Phase 3 assessed feasibility, efficacy, and safety with 8 pigs randomized into GMD (n = 4) or sham (SH, n = 4) and survived for 1 month. Body weights (GMD, n = 4, SH, n = 4) were measured daily in phase 3 for 1 month, and relative body weights were calculated and analyzed using one-tailed Student's t-test. Percent body fat was compared between GMD and SH at baseline and 1 month post-GMD. RESULTS: Phase 1 identified the optimal ablation parameters (120 W) that were then used in phase 2. Phase 2 revealed a trend that was suggestive that the optimal percent surface area to ablate was similar to that which is removed at laparoscopic sleeve gastrectomy. In phase 3, GMD was performed over 70% surface area of the greater curvature of the stomach in four pigs. GMD pigs had significantly lower relative body weight increase compared to SH at 1 month (1.375 ± 0.085 vs 1.575 ± 0.047, p = 0.0435). MRI showed a significantly lower body fat mass at 1 month in GMD pigs (5.9 ± 0.4% vs 12.7 ± 2.3%, p = 0.026) compared to SH. CONCLUSIONS: GMD resulted in decreased weight gain in the GMD group as evidenced by a lower relative body weight at 1 month. GMD in an animal model appears to show promise as a potential weight loss therapy.

Acute appendicitis severity during the early COVID-19 pandemic period.

BACKGROUND: The early COVID-19 pandemic period significantly strained the US healthcare system. During this period, consultations and admissions for acute medical conditions decreased, which was associated with an increase in disease-specific morbidity and mortality. Therefore, we sought to determine what, if any, effect the early COVID-19 pandemic period had on the presentation, management, and histopathologic severity of acute appendicitis. METHODS: We performed a retrospective, observational study to compare the frequencies with which patients presented with acute appendicitis, the proportion of whom were managed surgically, and the distribution of histopathologic disease severity among all resected appendix specimens during the early COVID-19 pandemic period (March 6-June 30, 2020) to equivalent time periods for the 3 preceding/pre-pandemic years (2017-2019). RESULTS: Compared with equivalent pre-pandemic time periods, during the COVID-19 pandemic period there was no significant difference in the number of patients who presented for acute appendicitis, there was a decreased rate of surgical management (81% vs 94%; p=0.014), and there was an overall increase in the incidence of perforated appendicitis (31% vs 16%; p=0.004), including by histopathologic diagnosis (25% vs 11%; p=0.01). DISCUSSION: Despite potential patient hesitancy to present for care, the early COVID-19 pandemic period was associated with no significant change in the number of patients presenting with acute appendicitis; however, there was a significant increase in the incidence of perforated appendicitis. This study highlights the need to encourage patients to avoid late presentation for acute surgical conditions and for the robust planning for the medical management of otherwise surgical abnormalities during episodes of restricted or limited resources. LEVEL OF EVIDENCE: Level III.

A patient-like swine model of gastrointestinal fibrotic strictures for advancing therapeutics.

Gastrointestinal (GI) strictures are difficult to treat in a variety of disease processes. Currently, there are no Food and Drug Administration (FDA) approved drugs for fibrosis in the GI tract. One of the limitations to developing anti-fibrotic drugs has been the lack of a reproducible, relatively inexpensive, large animal model of fibrosis-driven luminal stricture. This study aimed to evaluate the feasibility of creating a model of luminal GI tract strictures. Argon plasma coagulation (APC) was applied circumferentially in porcine esophagi in vivo. Follow-up endoscopy (EGD) was performed at day 14 after the APC procedure. We noted high grade, benign esophageal strictures (n = 8). All 8 strictures resembled luminal GI fibrotic strictures in humans. These strictures were characterized, and then successfully dilated. A repeat EGD was performed at day 28 after the APC procedure and found evidence of recurrent, high grade, fibrotic, strictures at all 8 locations in all pigs. Pigs were sacrificed and gross and histologic analyses performed. Histologic examination showed extensive fibrosis, with significant collagen deposition in the lamina propria and submucosa, as well as extensive inflammatory infiltrates within the strictures. In conclusion, we report a porcine model of luminal GI fibrotic stricture that has the potential to assist with developing novel anti-fibrotic therapies as well as endoscopic techniques to address recurring fibrotic strictures in humans.

Continuing Undergraduate Pathology Medical Education in the Coronavirus Disease 2019 (COVID-19) Global Pandemic: The Johns Hopkins Virtual Surgical Pathology Clinical Elective.

CONTEXT.­: In the early months of the response to the coronavirus disease 2019 (COVID-19) pandemic, the Johns Hopkins University School of Medicine (JHUSOM) (Baltimore, Maryland) leadership reached out to faculty to develop and implement virtual clinical clerkships after all in-person medical student clinical experiences were suspended. OBJECTIVE.­: To develop and implement a digital slide-based virtual surgical pathology (VSP) clinical elective to meet the demand for meaningful and robust virtual clinical electives in response to the temporary suspension of in-person clinical rotations at JHUSOM. DESIGN.­: The VSP elective was modeled after the in-person surgical pathology elective to include virtual previewing and sign-out with standardized cases supplemented by synchronous and asynchronous pathology educational content. RESULTS.­: Validation of existing Web communications technology and slide-scanning systems was performed by feasibility testing. Curriculum development included drafting of course objectives and syllabus, Blackboard course site design, electronic-lecture creation, communications with JHUSOM leadership, scheduling, and slide curation. Subjectively, the weekly schedule averaged 35 to 40 hours of asynchronous, synchronous, and independent content, approximately 10 to 11 hours of which were synchronous. As of February 2021, VSP has hosted 35 JHUSOM and 8 non-JHUSOM students, who have provided positive subjective and objective course feedback. CONCLUSIONS.­: The Johns Hopkins VSP elective provided meaningful clinical experience to 43 students in a time of immense online education need. Added benefits of implementing VSP included increased medical student exposure to pathology as a medical specialty and demonstration of how digital slides have the potential to improve standardization of the pathology clerkship curriculum.

Perianal Paget's disease as spread from non-invasive colorectal adenomas.

AIMS: Paget's disease of the perianal skin is a rare form of extramammary Paget's disease, and may be a primary intraepithelial adnexal neoplasm or secondary due to spread from an underlying colorectal lesion, nearly always colorectal adenocarcinoma. Secondary perianal Paget's disease associated with non-invasive colorectal adenomas is exceedingly uncommon, with only a few reported cases. METHODS AND RESULTS: Herein, we present the clinical and pathological features of the largest series of secondary perianal Paget's disease arising in association with colorectal adenomas. There was gender parity and the median age was 72 years (range = 68-76 years). In all cases, perianal Paget's disease was associated with colorectal adenomas, including three (75%) conventional tubular adenomas and one (25%) tubulovillous adenoma with serrated foci. All adenomas had high-grade dysplasia and one had intramucosal adenocarcinoma (lamina propria invasion; Tis), but all lacked submucosal invasion. The intraepithelial Paget's cells showed a colorectal phenotype by immunohistochemistry in all cases. At follow-up, two patients had no evidence of disease at 6 and 87 months, one had residual perianal Paget's disease at 8 months and one developed invasive adenocarcinoma of the perianal tissue at 36 months. CONCLUSIONS: Similar to its mammary analogue, secondary perianal Paget's disease may arise in association with invasive and/or in-situ colorectal lesions. Although the latter is an uncommon presentation of a recognised rare disease, knowledge of this phenomenon is important to forestall overdiagnosis of invasion and potential overtreatment. The clinical course is variable, such that close follow-up is required.

Targeting the Hedgehog Pathway Using Itraconazole to Prevent Progression of Barrett's Esophagus to Invasive Esophageal Adenocarcinoma.

OBJECTIVE: The aim of the study was to investigate whether inhibition of Sonic Hedgehog (SHH) pathway would prevent progression of Barrett's Esophagus (BE) to esophageal adenocarcinoma. BACKGROUND: The hedgehog signaling pathway is a leading candidate as a molecular mediator of BE and esophageal adenocarcinoma (EAC). Repurposed use of existing off-patent, safe and tolerable drugs that can inhibit hedgehog, such as itraconazole, could prevent progression of BE to EAC. METHODS: The efficacy of itraconazole was investigated using a surgical rat reflux model of Barrett's Metaplasia (BM). Weekly intraperitoneal injections of saline (control group) or itraconazole (treatment group; 200 mg/kg) were started at 24 weeks postsurgery. Esophageal tissue was harvested at 40 weeks. The role of the Hh pathway was also evaluated clinically. Esophageal tissue was harvested after 40 weeks for pathological examination and evaluation of the SHH pathway by immunohistochemistry. RESULTS: BM was present in control animals 29 of 31 (93%) versus itraconazole 22 of 24 (91%). EAC was significantly lower in itraconazole 2 of 24 (8%) versus control 10 of 31 (32%), respectively (P = 0.033). Esophageal SHH levels were lower in itraconazole vs control (P = 0.12). In esophageal tissue from humans with recurrent or persistent dysplastic BE within 24 months of ablative treatment, strong SHH and Indian Hedgehog expression occurred in distal BE versus proximal squamous epithelium, odds ratio = 6.1 (95% confidence interval: 1.6, 23.4) and odds ratio = 6.4 (95% confidence interval: 1.2, 32.8), respectively. CONCLUSION: Itraconazole significantly decreases EAC development and SHH expression in a preclinical animal model of BM. In humans, BE tissue expresses higher SHH, Indian Hedgehog, and bone morphogenic protein levels than normal squamous esophageal epithelium.

Cell polarity (the 'four lines') distinguishes gastric dysplasia from epithelial changes in reactive gastropathy.

AIMS: Gastric dysplasia is a risk factor for synchronous and subsequent gastric carcinoma. Distinguishing gastric dysplasia from reactive changes is subject to interobserver disagreement and is a frequent reason for expert consultation. We previously used assessment of surface cell polarity (the 'four lines') as a key feature to decrease equivocal diagnoses in Barrett oesophagus. In the current study, we examined for the presence or absence of the four lines in gastric dysplasia and reactive gastropathy. MATERIALS AND METHODS: The study includes all (n = 91) in-house biopsies with at least gastric dysplasia from the surgical pathology archives of two academic institutions during a 5-year period from 2008 to 2012. A reactive gastropathy group (n = 60) was created for comparison. RESULTS: The dysplasia/neoplasia group was comprised of 14 biopsies of gastric foveolar-type dysplasia, 59 of intestinal-type dysplasia, 14 with dysplasia in fundic gland polyps, three pyloric gland adenomas and one oxyntic gland adenoma. Loss of surface cell polarity was seen in all 88 dysplasia cases with evaluable surface epithelium. All 57 reactive gastropathy cases with evaluable surface epithelium showed intact surface cell polarity except in focal areas directly adjacent to erosions in 17 cases, where the thin wisp of residual surface mucin could not be appreciated on haematoxylin and eosin. CONCLUSION: Surface cell polarity (the four lines) was lost in all gastric dysplasia biopsies with evaluable surface epithelium and maintained in all biopsies of reactive gastropathy. Caution should be taken in using this feature adjacent to erosions in reactive gastropathy.

Intra-abdominal lymphangioma: A case report.

Lymphangioma is a rare, benign congenital malformation of the lymphatic system that usually affects the neck and head in children. Intra-abdominal lymphangioma accounts for less than 5 percent of all cases of lymphangioma. The clinical presentation of intra-abdominal lymphangioma can vary from asymptomatic to nausea, vomiting, and abdominal pain. The diagnosis of intra-abdominal lymphangioma is based on imaging modalities and histopathological examination. The definitive treatment is surgical resection. Here we describe the interesting and rare case of a 29-year-old woman with lymphangioma of the retroperitoneum extending to the root of the mesentery. We focus on the diagnosis and management of this rare tumor by the application of radiological modalities and pathological analysis.

Pancreatic cystic desmoid tumor following metastatic colon cancer surgery: A case report.

Desmoid tumors are rare, benign, and locally aggressive neoplasms that stem from connective tissue that have high rates of recurrence after surgery. Intra-abdominal desmoid-type fibromatosis can arise in 2 forms: sporadic or hereditary (associated with familial adenomatous polyposis and Gardner syndrome). The diagnosis of desmoid-type tumors is based on imaging modalities and histopathological examination. The primary treatment is resection surgery. We report a 64-year-old male with a distal pancreatic desmoid tumor. We focus on tumor management by the application of radiological modalities and pathological analysis.

Deep Adversarial Training for Multi-Organ Nuclei Segmentation in Histopathology Images.

Nuclei mymargin segmentation is a fundamental task for various computational pathology applications including nuclei morphology analysis, cell type classification, and cancer grading. Deep learning has emerged as a powerful approach to segmenting nuclei but the accuracy of convolutional neural networks (CNNs) depends on the volume and the quality of labeled histopathology data for training. In particular, conventional CNN-based approaches lack structured prediction capabilities, which are required to distinguish overlapping and clumped nuclei. Here, we present an approach to nuclei segmentation that overcomes these challenges by utilizing a conditional generative adversarial network (cGAN) trained with synthetic and real data. We generate a large dataset of H&E training images with perfect nuclei segmentation labels using an unpaired GAN framework. This synthetic data along with real histopathology data from six different organs are used to train a conditional GAN with spectral normalization and gradient penalty for nuclei segmentation. This adversarial regression framework enforces higher-order spacial-consistency when compared to conventional CNN models. We demonstrate that this nuclei segmentation approach generalizes across different organs, sites, patients and disease states, and outperforms conventional approaches, especially in isolating individual and overlapping nuclei.

Wide-field optical property mapping and structured light imaging of the esophagus with spatial frequency domain imaging.

As the incidence of esophageal adenocarcinoma continues to rise, there is a need for improved imaging technologies with contrast to abnormal esophageal tissues. To inform the design of optical technologies that meet this need, we characterize the spatial distribution of the scattering and absorption properties from 471 to 851 nm of eight resected human esophagi tissues using Spatial Frequency Domain Imaging. Histopathology was used to categorize tissue types, including normal, inflammation, fibrotic, ulceration, Barrett's Esophagus and squamous cell carcinoma. Average absorption and reduced scattering coefficients of normal tissues were 0.211 ± 0.051 and 1.20 ± 0.18 mm-1 , respectively at 471 nm, and both values decreased monotonically with increasing wavelength. Fibrotic tissue exhibited at least 68% larger scattering signal across all wavelengths, while squamous cell carcinoma exhibited a 36% decrease in scattering at 471 nm. We additionally image the esophagus with high spatial frequencies up to 0.5 mm-1 and show strong reflectance contrast to tissue treated with radiation. Lastly, we observe that esophageal absorption and scattering values change by an average of 9.4% and 2.7% respectively over a 30 minute duration post-resection. These results may guide system design for the diagnosis, prevention and monitoring of esophageal pathologies.

Refined Criteria for Separating Low-grade Dysplasia and Nondysplastic Barrett Esophagus Reduce Equivocal Diagnoses and Improve Prediction of Patient Outcome: A 10-Year Review.

The indefinite for dysplasia (IFD) category in Barrett esophagus (BE) is used for biopsies that are neither unequivocally dysplastic nor negative for dysplasia (NFD). In 2012, we refined our criteria so that BE with maintained cell polarity and surface gastric-type mucin vacuoles is considered NFD even with mild to moderate nuclear enlargement. A total of 1549 cases from 1130 patients with BE biopsies were identified from 2007 to 2016. Follow-up on patients with IFD biopsies was obtained to learn if the new thresholds better defined risk of progression. The earlier cases (2007-2011) were less likely than later cases (2012-2016) to be NFD (84.0% vs. 90.4%) and more likely to be IFD (8.4% vs. 4.3%). The proportions of low-grade dysplasia (3.9% vs. 2.5%, high-grade dysplasia (1.4% vs. 1.3%), and intramucosal carcinoma (2.3% vs. 1.6%) were similar between the earlier and later cases, respectively. Later IFD cases were more frequently dysplastic (3/21, 14.3%) on the next biopsy than earlier cases (1/48, 2.1%). The rate of dysplasia on the next biopsy for NFD cases was not higher in the later cases (6/222, 2.7%) than the earlier cases (16/360, 4.4%). Improved diagnostic criteria reduced the proportion of IFD cases by nearly 50% from 2007 to 2016. This change coincided with a higher proportion of IFD cases having dysplasia on the next biopsy. NFD patients had no increase in dysplasia on the next biopsy providing evidence that dysplastic cases are not missed by the refined criteria.

V600E BRAF versus Non-V600E BRAF Mutated Lung Adenocarcinomas: Cytomorphology, Histology, Coexistence of Other Driver Mutations and Patient Characteristics.

OBJECTIVES: We analyzed the morphologic features and clinical characteristics of lung adenocarcinomas (ACAs) harboring mutated BRAF. STUDY DESIGN: A review of the histology/cytology of BRAF-mutated lung ACAs was performed at the Johns Hopkins Hospital from January 1, 2013, to January 1, 2015. Patient demographics, clinical history, and ACA morphology were assessed. RESULTS: Thirty-six cases were identified with a median age of 66 years (range 44-87), 58% (21/36) were female, and 94% (34/36) were current or former smokers. In total, 28% (10/36) had a BRAF-V600E mutation. Concurrent mutations were identified in KRAS in 4 cases (11%), PIK3CA in 2 cases (6%), and AKT1 in 2 cases (6%). No cases tested for ALK rearrangement were positive. The tumor grading varied from well to poorly differentiated, and the architecture assumed various patterns, including papillary, micropapillary, solid/cribriform, lepidic, and acinar. Of the cases with immunostains, 90% (18/20) were TTF-1 positive, 88% (14/16) were napsin-A positive, and 100% (8/8) were P63 negative. CONCLUSION: Mutated-BRAF lung ACA arose on average in the seventh decade of life in patients who were current or former smokers and was infrequently found in combination with other common lung ACA driver mutations. The actionable V600E mutation was present in <30% of cases, more commonly in females. The histologic grade and architecture of these tumors varied significantly.