Whole slide imaging in cytopathology education

Rapid advances are occurring in the field of cytopathology education and training. Web-based cytopathology educational resources and whole slide imaging (WSI) have revolutionized cytopathology education and helped to centralize the cytopathology resources enabling simultaneous delivery of interactive cytopathology educational programs to a wide range of students and learners nationally and across the globe. WSI is playing a central role in digital pathology and are being utilized as an educational tool in many areas of pathology and cytopathology. This is mainly due to their easy access from anywhere and anytime, with no need for replication of glass slides or a big concern about the issue of protection of patient privacy. Today, WSI is used in a variety of educational settings, as a substitute to multi-headed microscopic sessions, multisite conferences, cytopathology web pages, self-assessment in cytology, cytology proficiency testing, virtual atlases, and very recently in scientific publications.     

Validation of whole slide imaging for frozen section diagnosis of lymph node metastasis: A retrospective study from a tertiary care hospital in Thailand

BackgroundThe use of whole slide imaging (WSI) for frozen section (FS) diagnosis is helpful, particularly in the context of pathologist shortages. However, there is minimal data on such usage in resource-limited settings. This study aims to validate the use of WSI for FS diagnosis of lymph node metastasis using a low-cost virtual microscope scanner with consumer-grade laptops at a tertiary care hospital in Thailand.MethodsFS slides were retrieved for which the clinical query was to evaluate lymph node metastasis. They were digitized by a virtual microscope scanner (MoticEasyScan, Hong Kong) using up to 40× optical magnification. Three observers with different pathology experience levels diagnosed each slide, reviewing glass slides (GS) followed by digital slides (DS) after two weeks of a wash out period. WSI and GS diagnoses were compared. The time used for scanning and diagnosis of each slide was recorded.Results295 FS slides were retrieved and digitized. The first-time successful scanning rate was 93.6 %. The mean scanning time was 2 min per slide. Both intraobserver agreement and interobserver agreement of WSI and GS diagnoses were high (Cohen's K; kappa value >0.84). The time used for DS diagnosis decreased as the observer's experience with WSI increased.ConclusionsDespite varying pathological experiences, observers using WSI provided accurate FS diagnoses of lymph node metastasis. The time required for DS diagnoses decreased with additional observer's experience with WSI. Therefore, a WSI system containing low-cost scanners and consumer-grade laptops could be used for FS services in hospital laboratories lacking pathologists.     

Evaluation of whole slide image immunohistochemistry interpretation in challenging prostate needle biopsies

Whole slide images (WSIs), also known as virtual slides, can support electronic distribution of immunohistochemistry (IHC) stains to pathologists that rely on remote sites for these services. This may lead to improvement in turnaround times, reduction of courier costs, fewer errors in slide distribution, and automated image analyses. Although this approach is practiced de facto today in some large laboratories, there are no clinical validation studies on this approach. Our retrospective study evaluated the interpretation of IHC stains performed in difficult prostate biopsies using WSIs. The study included 30 foci with IHC stains identified by the original pathologist as both difficult and pivotal to the final diagnosis. WSIs were created from the glass slides using a scanning robot (T2, Aperio Technologies, Vista, CA). An evaluation form was designed to capture data in 2 phases: (1) interpretation of WSIs and (2) interpretation of glass slides. Data included stain interpretations, diagnoses, and other parameters such as time required to diagnose and image/slide quality. Data were also collected from an expert prostate pathologist, consensus meetings, and a poststudy focus group. WSI diagnostic validity (intraobserver pairwise kappa statistics) was "almost perfect" for 1 pathologist, "substantial" for 3 pathologists, and "moderate" for 1 pathologist. Diagnostic agreement between the final/consensus diagnoses of the group and those of the domain expert was "almost perfect" (kappa = 0.817). Except for one instance, WSI technology was not felt to be the cause of disagreements. These results are encouraging and compare favorably with other efforts to quantify diagnostic variability in surgical pathology. With thorough training, careful validation of specific applications, and regular postsignout review of glass IHC slides (eg, quality assurance review), WSI technology can be used for IHC stain interpretation.     

Whole-slide imaging in cytopathology: state of the art and future directions

Whole slide imaging (WSI) has been increasingly adopted for digital evaluation of surgical pathology specimens. Unlike histological slides, cytological preparations frequently display a heterogeneous distribution of cells throughout slides in different focal planes sometimes admixed with obscuring material, therefore requiring multiple scanning planes which significantly lengthens image acquisition and evaluation times. Although examination of digital images can be more advantageous than conventional glass slides, the challenges of focusing, scanning and screening cytological specimens and the associated increase in scan times and data storage needs have limited the routine application of WSI in cytopathology practice. Emerging digital systems designed to overcome image acquisition obstacles coupled with artificial intelligence algorithms augmenting screening of digital cytology slides offer innovative solutions to address these limitations. The aim of this review is to critically address the potential benefits and pitfalls of employing WSI in cytopathology practice and to introduce promising state-of-the-art solutions on the horizon.     

Whole-slide imaging: widening the scope of cytopathology

Whole slide imaging (WSI) is broadening the scope of cytopathology. Whole slide images are being used for telecytology, quality assurance activities (e.g. proficiency testing) and teaching (e.g. digital teaching sets and online virtual atlases). Progress in WSI technology that permits high resolution scanning, z-stacking, and hybrid robotic devices has encouraged the use of this imaging modality for cytology practice, education and research. However, widespread adoption in cytology still depends on overcoming barriers unrelated to cytology and challenges directly related to digitizing cytopathology slides. The aim of this article is to review WSI technology, applications and limitations specific to cytopathology.     

Digital pathology: current status and future perspectives

During the last decade pathology has benefited from the rapid progress of image digitizing technology. The improvement in this technology had led to the creation of slide scanners which are able to produce whole slide images (WSI) which can be explored by image viewers in a way comparable to the conventional microscope. The file size of the WSI ranges from a few megabytes to several gigabytes, leading to challenges in the area of image storage and management when they will be used routinely in daily clinical practice. Digital slides are used in pathology for education, diagnostic purposes (clinicopathological meetings, consultations, revisions, slide panels and, increasingly, for upfront clinical diagnostics) and archiving. As an alternative to conventional slides, WSI are generally well accepted, especially in education, where they are available to a large number of students with the full possibilities of annotations without the problem of variation between serial sections. Image processing techniques can also be applied to WSI, providing pathologists with tools assisting in the diagnosis-making process. This paper will highlight the current status of digital pathology applications and its impact on the field of pathology.     

Use of whole slide imaging in surgical pathology quality assurance: design and pilot validation studies

By imaging large numbers of slides automatically at high resolution, modem automated whole slide imaging (WSI) systems have the potential to become useful tools in pathology practice. This article describes a pilot validation study for use of automated high-speed WSI systems for surgical pathology quality assurance (QA). This was a retrospective comparative study in which 24 full genitourinary cases (including 47 surgical parts and 391 slides) were independently reviewed with traditional microscopy and whole slide digital images. Approximately half the cases had neoplasia in the diagnostic line. At the end of the study, diagnostic discrepancies were evaluated by a pathology consensus committee. The study pathologists felt that the traditional and WSI methods were comparable for case review. They reported no difference in perceived case complexity or diagnostic confidence between the methods. There were 4 clinically insignificant discrepancies with the signed-out cases: 2 from glass slide and 2 with WSI review. Of the 2 discrepancies reported by the WSI method, the committee agreed with the reviewer once and the original report once. At the end of the study, the participants agreed that automated WSI is a viable potential modality for surgical pathology QA, especially in multifacility health systems that would like to establish interfacility QA. The participants felt that major issues limiting the implementation of WSI-based QA did not involve image acquisition or quality but rather image management issues such as the pathologist's interface, the hospital's network, and integration with the laboratory information system.     

Evaluation of the use of digital images for a national prostate core external quality assurance scheme

Harnden P, Coleman D, Moss S, Kodikara S, Griffin N R & Melia J

(2011) Histopathology 59 , 703–709 Evaluation of the use of digital images for a national prostate core external quality assurance scheme Aims: To evaluate the use of virtual images as an alternative to glass slides to expand the number of participants in the External Quality Assurance Scheme for prostatic biopsies. Methods and results: Benign and neoplastic cases, previously circulated as glass slides, were selected to include cases that had demonstrated a high level of agreement (n = 10) and a lesser degree of agreement (n = 10). Whole slide virtual images were circulated to 68 pathologists; 51 responses were returned. The levels of agreement for the primary diagnosis and for Gleason grading of cancers were analysed using kappa statistics. Responses for glass slides versus images were compared for the 24 pathologists for whom data were available. Levels of agreement for diagnostic categories using virtual slides were moderate to substantial, comparable to those found using glass slides. The level of agreement for Gleason grades 8–10 was substantial, but for lower grades was fair or moderate, poorer than for the glass slide circulation. Conclusions: Circulation of virtual images of biopsy material is a suitable alternative to glass slide‐based schemes for the evaluation of diagnostic consistency. The majority of participants agreed that the ability to evaluate limited diagnostic material outweighed the disadvantages of a virtual system.     

Application of virtual microscopy in clinical cytopathology.

Virtual microscopy (VM) refers to the use of an automated microscope and digital imaging technology to scan, store, and view glass slides. VM systems allow the user to view a scanned image of the entire slide at multiple magnifications on a computer screen. We tested VM to evaluate its possible utility in diagnostic cytopathology. Ten cervical-vaginal monolayered preparations (AutoCyte preparation) were scanned using a BLISS (Bacus Laboratories Inc. Slide Scanner) system. Approximately 20-30% of the cellular area of each slide was imaged. The cases were randomly chosen to include examples ranging from benign cellular changes (BCC) to high-grade squamous intraepithelial lesions (HSIL). The computer performed image tiling and fusing of multiple JPEG images to create a high-quality VM slide. Six examiners (two each of cytopathologists, senior residents, and cytotechnologists) blindly evaluated the VM slides using an image server program (WebSlide Browser thin client software). The cytopathologic diagnoses made on the VM slide were then compared to the original glass slide diagnoses. BLISS took 36-100 min (avg. 58.4 min) to scan the selected fields in a glass slide with file sizes ranging from 23.1-83.6 MB. Time taken by the examiners to render a diagnosis ranged from 1-15 min (avg. 4.1 min) per case. The combined diagnostic accuracy was 98.3%. Only one case of LSIL was missed by one examiner. VM is a promising new tool, which gives a user the feel and simulated experience of an actual microscopic examination and provides a useful alternative to a glass slide in diagnostic cytopathology. Possible applications include: 1) second opinion consultation without transporting the glass slide, 2) education, 3) VM proficiency tests / board exams, and 4) telepathology. Shortcomings include 1) expensive initial setup, 2) inability to maintain an adequate focus in a thick smear with multiple levels, 3) large storage size of the VM slide, and 4) relatively long time needed to scan a slide.     

Implementation of virtual microscope slides in the annual pathobiology of cancer workshop laboratory

Virtual slides are digital facsimiles of glass microscope slides that, when viewed with a pan and zoom viewer, can emulate viewing a glass slide with a traditional microscope. Based on successful implementation of virtual slides in medical student histology and pathology courses at the University of Iowa, we developed a plan to evaluate the use of virtual slides in the American Association for Cancer Research's annual Pathobiology of Cancer Workshop. In this Workshop, nonphysician predoctoral students and postdoctoral fellows working in cancer research explore the morphological, clinical, and molecular aspects of human cancer. Over the course of a week, students examine approximately 100 glass slides in microscope laboratories, facilitated by senior cancer investigators. The goal of the present study was to evaluate virtual slides as a teaching modality in these laboratories, not as a replacement for traditional microscopy, but rather in terms of their utility in facilitating student learning as they examine glass slides with a traditional microscope. Evaluation by questionnaire indicated that virtual slides enhanced students' ability to grasp morphological features better than the traditional photomicrographs. The results of this implementation suggest that virtual slide technology may be successfully extended to other educational venues where traditional microscopy and photomicrographs are currently used.     

Eye-movement study and human performance using telepathology virtual slides: implications for medical education and differences with experience

A core skill in diagnostic pathology is light microscopy. Remarkably little is known about human factors that affect the proficiency of pathologists as light microscopists. The cognitive skills of pathologists have received relatively little attention in comparison with the large literature on human performance studies in radiology. One reason for this lack of formal visual search studies in pathology has been the physical restrictions imposed by the close positioning of a microscope operator's head to the microscope's eyepieces. This blocks access to the operator's eyes and precludes assessment of the microscopist's eye movements. Virtual slide microscopy now removes this barrier and opens the door for studies on human factors and visual search strategies in light microscopy. The aim of this study was to assess eye movements of medical students, pathology residents, and practicing pathologists examining virtual slides on a digital display monitor. Whole histopathology glass slide digital images, so-called virtual slides, of 20 consecutive breast core biopsy cases were used in a retrospective study. These high-quality virtual slides were produced with an array-microscope equipped DMetrix DX-40 ultrarapid virtual slide processor (DMetrix, Tucson, Ariz). Using an eye-tracking device, we demonstrated for the first time that when a virtual slide reader initially looks at a virtual slide his or her eyes are very quickly attracted to regions of interest (ROIs) within the slide and that these ROIs are likely to contain diagnostic information. In a matter of seconds, critical decisions are made on the selection of ROIs for further examination at higher magnification. We recorded: (1) the time virtual slide readers spent fixating on self-selected locations on the video monitor; (2) the characteristics of the ways the eyes jumped between fixation locations; and (3) x and y coordinates for each virtual slide marking the sites the virtual slide readers manually selected for zooming to higher ROI magnifications. We correlated the locations of the visually selected fixation locations and the manually selected ROIs. Viewing profiles were identified for each group. Fully trained pathologists spent significantly less time (mean, 4.471 seconds) scanning virtual slides when compared to pathology residents (mean, 7.148 seconds) or medical students (mean, 11.861 seconds), but had relatively prolonged saccadic eye movements (P < .0001). Saccadic eye movements are defined as eye movements between fixation locations. On the other hand, the pathologists spent significantly more time than trainees dwelling on the 3 locations they subsequently chose for zooming. Unlike either the medical students or the residents, the pathologists frequently choose areas for viewing at higher magnification outside of areas of foveal (central) vision. Eye movement studies of scanning pathways (scan paths) may be useful for developing eye movement profiles for individuals and for understanding the difference in performances between novices and experts. They may also be useful for developing new visual search strategies for rendering diagnoses on telepathology virtual slides.     

Virtual microscopy and digital pathology in training and education

Traditionally, education and training in pathology has been delivered using textbooks, glass slides and conventional microscopy. Over the last two decades, the number of web-based pathology resources has expanded dramatically with centralized pathological resources being delivered to many students simultaneously. Recently, whole slide imaging technology allows glass slides to be scanned and viewed on a computer screen via dedicated software. This technology is referred to as virtual microscopy and has created enormous opportunities in pathological training and education. Students are able to learn key histopathological skills, e.g. to identify areas of diagnostic relevance from an entire slide, via a web-based computer environment. Students no longer need to be in the same room as the slides. New human-computer interfaces are also being developed using more natural touch technology to enhance the manipulation of digitized slides. Several major initiatives are also underway introducing online competency and diagnostic decision analysis using virtual microscopy and have important future roles in accreditation and recertification. Finally, researchers are investigating how pathological decision-making is achieved using virtual microscopy and modern eye-tracking devices. Virtual microscopy and digital pathology will continue to improve how pathology training and education is delivered.     

The virtual case: a new method to completely digitize cytological and histological slides

The purpose of this study was to present a new method for handling histological/cytological cases. Thanks to the introduction of information technology in pathology, including the amenities afforded by robotic microscopes and digital imaging, tissue slides can be represented and evaluated using digital techniques in order to construct virtual cases through completely automated procedures. A virtual case (VC) is composed of a collection of digital images representing a histological/cytological slide at all magnification levels together with all relevant clinical data. In the present study, we describe an automated system to manage robotic microscope and image acquisition for the proper construction of VCs. These can then be viewed on a computer by means of an interface ("user-friendly") that allows one to select the more appropriate fields and to examine them at different magnifications, rapidly going from panoramic views to high resolution and vice versa. In comparison with glass slides, VCs have several advantages arising from their digital nature and can be considered a common platform for a wide range of applications such as teleconsultation, education, research, and quality control and proficiency tests.     

Use of virtual microscopy for didactic live-audience presentation in anatomic pathology

Didactic presentations on the topic of anatomic pathology in front of a live audience have been largely dependent on the use of standard 2 x 2 inch projection slides (Kodachromes) of selected still images from the topic at hand. Because of the highly visual nature of the specialty of anatomic pathology, this method has had some serious limitations. With the advent of digital imaging techniques and the availability of new electronic software for the projection of images, new possibilities have become available for didactic presentations in anatomic pathology in front of a large, live audience. We describe a method whereby large digital images or "virtual slides" were produced from digitally scanned whole-mount sections of histologic glass slides and projected using a combination of PowerPoint (Microsoft Corp, Redmond, WA) and virtual microscopy in front of a live audience. To provide a seamless transition between the two presentation formats, the personal computer-based PowerPoint slides were hyperlinked to a browser-based virtual microscope viewer. The presenter, with the use of a mouse, was able to "move" the image of the scanned slide on the screen, to transition seamlessly among various magnifications, and to rapidly select from the whole-mount scanned slide among any areas of interest pertinent to the topic. Thus, the visual experience obtained by the audience simulated that of viewing a glass slide at a multi-headed microscope during a glass slide tutorial. Because this most closely approximates the experience of reviewing glass slides under the microscope for practicing pathologists, the educational experience of the presentation is greatly enhanced by the use of this technique. Also, this method permits making this type of presentation available to a much larger group of individuals in a live audience.     

Primary histologic diagnosis using automated whole slide imaging: a validation study

Background  

Only prototypes 5 years ago, high-speed, automated whole slide imaging (WSI) systems (also called digital slide systems, virtual microscopes or wide field imagers) are becoming increasingly capable and robust. Modern devices can capture a slide in 5 minutes at spatial sampling periods of less than 0.5 micron/pixel. The capacity to rapidly digitize large numbers of slides should eventually have a profound, positive impact on pathology. It is important, however, that pathologists validate these systems during development, not only to identify their limitations but to guide their evolution.     

Evaluation of immunohistochemical staining using whole-slide imaging for HER2 scoring of breast cancer in comparison with real glass slides

Whole‐slide imaging (WSI) has been used for education and histological image preservation, and several studies have also reported its validity for practical pathological diagnosis. However, such studies employed materials stained with hematoxylin‐eosin (HE), and very few attempts have been made to use immunohistochemically stained materials for diagnostic purposes. In the present study, we investigated the availability of WSI diagnosis for immunohistochemically stained materials in place of routine glass slides. Thirty pathologists participated in a trial of HER2 expression diagnosis using WSI and compared the results with those obtained by light microscopy. The validity of WSI diagnosis (interobserver agreement) was rated as ‘substantial’ in comparison with glass slide diagnosis (κ‐value = 0.719). There was a tendency for observers to assign higher scores with WSI than with glass slides, probably because WSI requires slides to be scanned into a computer and observed via a monitor. Although we were able to demonstrate the potential utility of WSI for diagnosing immunostained materials, it must be borne in mind that there are some differences in visualization between WSI and glass slides.     

Critical comparison of 31 commercially available digital slide systems in pathology

Advances in new technologies for complete slide digitization in pathology have allowed the appearance of a wide spectrum of technologic solutions for whole-slide scanning, which have been classified into motorized microscopes and scanners. This article describes technical aspects of 31 different digital microscopy systems. The most relevant characteristics of the scanning devices are described, including the cameras used, the speed of digitization, and the image quality. Other aspects, such as the file format, the compression techniques, and the solutions for visualization of digital slides, (including diagnosis-aided tools) are also considered. Most of the systems evaluated allow a high-resolution digitization of the whole slide within about 1 hour using a x40 objective. The image quality of the current virtual microscopy systems is suitable for clinical, educational, and research purposes. The efficient use of digital microscopy by means of image analysis systems can offer important benefits to pathology departments.     

Loss of fidelity in scanned digital images compared to glass slides of brain tumors resected using cavitron ultrasonic surgical aspirator

Conversion of glass slides to digital images is necessary to capitalize on advances in computational pathology and could potentially transform our approach to primary diagnosis, research, and medical education. Most slide scanners have a limited maximum scannable area and utilize proprietary tissue detection algorithms to selectively scan regions that contain tissue, allowing for increased scanning speed and reduced file size compared to scanning the entire slide at high resolution. However, very small and faintly stained tissue fragments may not be recognized by these algorithms, leading to loss of fidelity in the digital image compared to the glass slides. Cavitron ultrasonic surgical aspirator (CUSA) is frequently used in brain tumor resections, resulting in highly fragmented specimens that are used for primary diagnosis. Here we evaluated the rate of loss of fidelity in 296 digital images from 40 CUSA‐resected brain tumors scanned using a Philips Ultra Fast Scanner. Overall, 54% of the slides (at least one from every case) showed loss of fidelity, with at least one tissue fragment not scanned at high resolution. The majority of the missed tissue fragments were small (<0.5 mm), but rare slides were missing fragments greater than 5 mm in greatest dimension. In addition, 19% of the slides with missing tissue showed no indication of loss of fidelity in the digital image itself; the missing tissue could only be appreciated upon review of the glass slides. These results highlight a potential liability in the use of digital images for primary diagnosis in CUSA‐resected brain tumor specimens.     

An array microscope for ultrarapid virtual slide processing and telepathology. Design, fabrication, and validation study

This paper describes the design and fabrication of a novel array microscope for the first ultrarapid virtual slide processor (DMetrix DX-40 digital slide scanner). The array microscope optics consists of a stack of three 80-element 10 x 8-lenslet arrays, constituting a "lenslet array ensemble." The lenslet array ensemble is positioned over a glass slide. Uniquely shaped lenses in each of the lenslet arrays, arranged perpendicular to the glass slide constitute a single "miniaturized microscope." A high-pixel-density image sensor is attached to the top of the lenslet array ensemble. In operation, the lenslet array ensemble is transported by a motorized mechanism relative to the long axis of a glass slide. Each of the 80 miniaturized microscopes has a lateral field of view of 250 microns. The microscopes of each row of the array are offset from the microscopes in other rows. Scanning a glass slide with the array microscope produces seamless two-dimensional image data of the entire slide, that is, a virtual slide. The optical system has a numerical aperture of N.A.= 0.65, scans slides at a rate of 3 mm per second, and accrues up to 3,000 images per second from each of the 80 miniaturized microscopes. In the ultrarapid virtual slide processing cycle, the time for image acquisition takes 58 seconds for a 2.25 cm2 tissue section. An automatic slide loader enables the scanner to process up to 40 slides per hour without operator intervention. Slide scanning and image processing are done concurrently so that post-scan processing is eliminated. A virtual slide can be viewed over the Internet immediately after the scanning is complete. A validation study compared the diagnostic accuracy of pathologist case readers using array microscopy (with images viewed as virtual slides) and conventional light microscopy. Four senior pathologists diagnosed 30 breast surgical pathology cases each using both imaging modes, but on separate occasions. Of 120 case reads by array microscopy, there were 3 incorrect diagnoses, all of which were made on difficult cases with equivocal diagnoses by light microscopy. There was a strong correlation between array microscopy vs. "truth" diagnoses based on surgical pathology reports. The kappa statistic for the array microscopy vs. truth was 0.96, which is highly significant (z=10.33, p <0.001). There was no statistically significant difference between rates of agreement with truth between array microscopy and light microscopy (z=0.134, p >0.05). Array microscopy and light microscopy did not differ significantly with respect to the number/percent of correct decisions rendered (t=0.552, p=0.6376) or equivocal decisions rendered (t=2.449, p=0.0917). Pathologists rated 95.8% of array microscopy virtual slide images as good or excellent. None were rated as poor. The mean viewing time for a DMetrix virtual slide was 1.16 minutes. The DMetrix virtual slide processor has been found to reduce the virtual slide processing cycle more than 10 fold, as compared with other virtual slide systems reported to date. The virtual slide images are of high quality and suitable for diagnostic pathology, second opinions, expert opinions, clinical trials, education, and research.     

Remote pathology education during the COVID-19 era: Crisis converted to opportunity

ContextThe COVID-19 pandemic led to shutting of education faculties, including clinical clerkships for medical students.ObjectiveTo review a selective for a course in diagnostic pathology geared toward undergraduate medical students, including its design, technical implementation, instructor and student evaluations, and suggestions for options for further adjusting and optimizing the selective.DesignWhole slide images (WSI) were anonymized and students were given remote access to university computers, which were prepared with two freely available WSI viewers. Each topic was taught in a four-part module: Self-assigned reading, lecture via Zoom, quiz based on digital slide sets, and a frontal review of the slides via Zoom. Fifty-nine students participated in the selective. Following the course, students completed an anonymous questionnaire.ResultsOf the 59 participants, 42% (n = 25) responded. None of the respondents had any previous instruction in diagnostic pathology. Overall, the course was rated very favorably: 68% (n = 17) gave at least 3 points on a 4-point scale on questions relating to course interest, improvement in understanding of the covered diseases, and how strongly they would recommend a student take this course if given an option. The most significant disadvantage of the class, as reported by 80% (n = 20) were technical challenges in accessing the slides.ConclusionWe believe the course was a success and can be a model for future virtual pathology electives. Great effort should be done to provide technical support to the students. The selective demonstrated value for students and provided much-needed exposure to diagnostic pathology in clinical practice.