#InSituPathologists: how the #USCAP2015 meeting went viral on Twitter and founded the social media movement for the United States and Canadian Academy of Pathology.

Professional medical conferences over the past five years have seen an enormous increase in the use of Twitter in real-time, also known as "live-tweeting". At the United States and Canadian Academy of Pathology (USCAP) 2015 annual meeting, 24 attendees (the authors) volunteered to participate in a live-tweet group, the #InSituPathologists. This group, along with other attendees, kept the world updated via Twitter about the happenings at the annual meeting. There were 6,524 #USCAP2015 tweets made by 662 individual Twitter users; these generated 5,869,323 unique impressions (potential tweet-views) over a 13-day time span encompassing the dates of the annual meeting. Herein we document the successful implementation of the first official USCAP annual meeting live-tweet group, including the pros/cons of live-tweeting and other experiences of the original #InSituPathologists group members. No prior peer-reviewed publications to our knowledge have described in depth the use of an organized group to "live-tweet" a pathology meeting. We believe our group to be the first of its kind in the field of pathology.

Primary cutaneous perivascular epithelioid cell tumor (PEComa): Five new cases and review of the literature.

PEComas represent a family of uncommon mesenchymal tumors composed of "perivascular epithelioid cells" with a distinct immunophenotype that typically shows both myogenic and melanocytic differentiation. The PEComa family includes angiomyolipoma (AML), clear cell "sugar" tumor of the lung and extra pulmonary sites, lymphangioleiomyomatosis and clear cell myomelanocytic tumor of the falciform ligament/ligamentum teres. Very rarely, PEComas may arise in the skin. Primary cutaneous PEComas typically display a dermal proliferation of epithelioid cells with pale, clear, or granular pink cytoplasm arranged in nests and trabecula with an intervening arborizing network of delicate capillaries. Primary cutaneous PEComas have a lower frequency of myogenic marker expression than their deep soft tissue and visceral counterparts. They also often express strong diffuse CD10, leading to potential confusion with metastatic renal cell carcinoma. Most cases behave indolently. We report 5 additional cases of this rare entity. All showed classic histologic features and expression of either HMB-45 and/or Melan-A/MART-1. Four cases were tested for myogenic markers (2 were positive & 2 were negative). Three cases were tested for CD10 (all 3 were positive). All of our cases with clinical follow-up behaved indolently. Table 1 provides a summary of findings for all 5 cases in our series.

Utility of additional tissue sections in dermatopathology: diagnostic, clinical and financial implications.

BACKGROUND: As histopathologic assessment is subject to sampling error, some institutions 'preorder' deeper sections on some or all cases (hereafter referred to as prospective deeper sections), while others order additional sections only when needed (hereafter referred to as retrospective deeper sections). We investigated how often additional sections changed a diagnosis and/or clinical management. Given the recent decrease in reimbursement for CPT-code 88305, we also considered the financial implications of ordering additional sections. METHODS: Cases (n = 204) were assigned a preliminary diagnosis, based on review of the initial slide, and a final diagnosis, after reviewing additional sections. Cases with discordant diagnoses were assessed by two dermatologists, who indicated whether the change in diagnosis altered clinical management. Expenses were estimated for three scenarios: (a) no additional sections, (b) prospective deeper sections and (c) retrospective deeper sections. RESULTS: Diagnoses were modified in 9% of cases, which changed clinical management in 56% of these cases. Lesions obtained by punch-biopsy and inflammatory lesions were disproportionately overrepresented amongst cases with changed diagnoses (p < 0.001, p = 0.12, respectively). The cost of prospective deeper sections and retrospective deeper sections represented a 56% and 115% increase over base costs, respectively. Labor costs, particularly the cost of dermatopathologist evaluation, were the most significant cost-drivers. CONCLUSIONS: While additional sections improve diagnostic accuracy, they delay turn-around-time and increase expenditures. In our practice, prospective deeper sections are cost effective, however, this may vary by institution.

Epithelioid sarcoma-like (pseudomyogenic) hemangioendothelioma, clinically mimicking dermatofibroma, diagnosed by skin biopsy in a 30-year-old man.

Epithelioid sarcoma-like (pseudomyogenic) hemangioendothelioma (ESHE) represents a rare soft tissue and bone tumor that typically presents as nodule(s) in the distal extremities of young adults. The nodules traverse several tissue planes simultaneously and can involve the dermis, subcutis, skeletal muscle and bone. ESHE shares clinical and microscopic features with epithelioid sarcoma (ES), and, accordingly, is commonly misdiagnosed as ES. However, unlike ES, which has a poor prognosis, ESHE commonly follows an indolent course. Herein, we report a case of ESHE diagnosed by skin biopsy that clinically mimicked a dermatofibroma. We also provide clinical photographs of the lesions in various stages of development, representing information that has not been previously published, to our knowledge.

Analytic Validation of Immunohistochemistry Assays: New Benchmark Data From a Survey of 1085 Laboratories.

CONTEXT: - A cooperative agreement between the College of American Pathologists (CAP) and the United States Centers for Disease Control and Prevention was undertaken to measure laboratories' awareness and implementation of an evidence-based laboratory practice guideline (LPG) on immunohistochemical (IHC) validation practices published in 2014. OBJECTIVE: - To establish new benchmark data on IHC laboratory practices. DESIGN: - A 2015 survey on IHC assay validation practices was sent to laboratories subscribed to specific CAP proficiency testing programs and to additional nonsubscribing laboratories that perform IHC testing. Specific questions were designed to capture laboratory practices not addressed in a 2010 survey. RESULTS: - The analysis was based on responses from 1085 laboratories that perform IHC staining. Ninety-six percent (809 of 844) always documented validation of IHC assays. Sixty percent (648 of 1078) had separate procedures for predictive and nonpredictive markers, 42.7% (220 of 515) had procedures for laboratory-developed tests, 50% (349 of 697) had procedures for testing cytologic specimens, and 46.2% (363 of 785) had procedures for testing decalcified specimens. Minimum case numbers were specified by 85.9% (720 of 838) of laboratories for nonpredictive markers and 76% (584 of 768) for predictive markers. Median concordance requirements were 95% for both types. For initial validation, 75.4% (538 of 714) of laboratories adopted the 20-case minimum for nonpredictive markers and 45.9% (266 of 579) adopted the 40-case minimum for predictive markers as outlined in the 2014 LPG. The most common method for validation was correlation with morphology and expected results. Laboratories also reported which assay changes necessitated revalidation and their minimum case requirements. CONCLUSIONS: - Benchmark data on current IHC validation practices and procedures may help laboratories understand the issues and influence further refinement of LPG recommendations.

Analytic Validation of Immunohistochemical Assays: A Comparison of Laboratory Practices Before and After Introduction of an Evidence-Based Guideline.

CONTEXT: - Laboratories must demonstrate analytic validity before any test can be used clinically, but studies have shown inconsistent practices in immunohistochemical assay validation. OBJECTIVE: - To assess changes in immunohistochemistry analytic validation practices after publication of an evidence-based laboratory practice guideline. DESIGN: - A survey on current immunohistochemistry assay validation practices and on the awareness and adoption of a recently published guideline was sent to subscribers enrolled in one of 3 relevant College of American Pathologists proficiency testing programs and to additional nonsubscribing laboratories that perform immunohistochemical testing. The results were compared with an earlier survey of validation practices. RESULTS: - Analysis was based on responses from 1085 laboratories that perform immunohistochemical staining. Of 1057 responses, 65.4% (691) were aware of the guideline recommendations before this survey was sent and 79.9% (550 of 688) of those have already adopted some or all of the recommendations. Compared with the 2010 survey, a significant number of laboratories now have written validation procedures for both predictive and nonpredictive marker assays and specifications for the minimum numbers of cases needed for validation. There was also significant improvement in compliance with validation requirements, with 99% (100 of 102) having validated their most recently introduced predictive marker assay, compared with 74.9% (326 of 435) in 2010. The difficulty in finding validation cases for rare antigens and resource limitations were cited as the biggest challenges in implementing the guideline. CONCLUSIONS: - Dissemination of the 2014 evidence-based guideline validation practices had a positive impact on laboratory performance; some or all of the recommendations have been adopted by nearly 80% of respondents.

Cytologic features of angiosarcoma: A review of 26 cases diagnosed on FNA.

BACKGROUND: This study describes the cytologic features of 26 angiosarcomas diagnosed on fine-needle aspiration. METHODS: Twenty-six angiosarcomas from 20 patients were confirmed by cytomorphology and immunocytochemical (immunohistochemistry) positivity for at least 2 of 3 vascular markers. Specimens were examined for spindled/epithelioid/plasmacytoid single cells, 3-dimensional clusters, multiple prominent/bar-shaped nucleoli (5 times longer than their width), chromatin strands, abnormal mitoses, necrosis, and vasoformative features. RESULTS: Eight males and 12 females with a mean age of 52 years (range, 2-94 years) underwent aspiration of tumors in the following: soft tissue or skin/subcutis (n = 10), bone (n = 4), nodes (n = 5), lung (n = 2), liver (n = 2), heart (n = 1), parotid gland (n = 1), and pleural fluid (n = 1). An angiosarcoma diagnosis was rendered for 24 of the 26 cases (92%); 1 was diagnosed as "atypical cells, cannot exclude angiosarcoma," and another was diagnosed as a malignant vascular neoplasm. Abnormal mitoses were most frequent (85%), and they were followed by single malignant cells (81%: epithelioid [69%], spindled [62%], and plasmacytoid [19%]), 3-dimensional clusters (54%), multiple prominent (62%) or bar-shaped nucleoli (54%), and chromatin strands (31%). Vasoformative features, including hemophagocytosis (54%), cytoplasmic lumina/vacuoles (69%) containing red blood cells (54%)/neutrophils (31%), and endothelial wrapping (69%), were seen in 88%; 23% had all vasoformative features, 88% had at least 1, and 12% had none. CONCLUSIONS: Angiosarcomas show a range of cytomorphologic features that make them potentially recognizable on cytology. Although vasoformative features are highly suggestive, they are not specific for angiosarcoma and may be seen in some nonvascular neoplasms. Immunohistochemistry and a high index of suspicion are required for an accurate diagnosis. Cancer Cytopathol 2016;124:659-68. © 2016 American Cancer Society.

Educational Value of Digital Whole Slides Accompanying Published Online Pathology Journal Articles: A Multi-Institutional Study.

CONTEXT: -Despite great interest in using whole slide imaging (WSI) in pathology practice and education, few pathology journals have published WSI pertinent to articles within their pages or as supplemental materials. OBJECTIVE: -To evaluate whether there is measurable added educational value of including WSI in publications. DESIGN: -Thirty-seven participants, 16 (43.3%), 15 (40.5%), and 6 (16.2%) junior pathology residents (postgraduate year 1-2), senior pathology residents (postgraduate year 3-4), and board-certified pathologists, respectively, read a sequence of 10 journal articles on a wide range of pathology topics. A randomized subgroup also reviewed the WSI published with the articles. Both groups completed a survey tool assessing recall of text-based content and of image-based material pertinent to the diseases but not present in the fixed published images. RESULTS: -The group examining WSI had higher performance scores in 72% of image-based questions (36 of 50 questions) as compared with the non-WSI group. As an internal study control, the WSI group had higher performance scores in only 40% of text-based questions (6 of 15 questions). The WSI group had significantly better performance than the non-WSI group for image-based questions compared with text-based questions (P < .05, Fisher exact test). CONCLUSION: -Our study provides supporting evidence that WSI offers enhanced value to the learner beyond the text and fixed images selected by the author. We strongly encourage more journals to incorporate WSI into their publications.