Primary Cutaneous Neuroendocrine Tumor of the Vulva: A Case Report.

Primary cutaneous neuroendocrine tumors (CNET) are extremely rare. Only a few cases have been reported so far. CNET have an indolent clinical course and usually present as a single flesh-colored nodule with a predilection for the scalp and trunk in elderly patients. While primary CNET have characteristic histological and immunohistochemical features akin to other low-grade neuroendocrine tumors elsewhere in the body, diagnosing these tumors on skin biopsies can be challenging as they are particularly mistaken for other, more commonly diagnosed, entities. In the current report we present a unique case of primary CNET of the vulva. The clinical presentation will be discussed as well as the histopathologic and immunohistochemical features and most importantly the possible pitfalls in microscopic examination.

Mitosis Counting in Breast Cancer: Object-Level Interobserver Agreement and Comparison to an Automatic Method.

BACKGROUND: Tumor proliferation speed, most commonly assessed by counting of mitotic figures in histological slide preparations, is an important biomarker for breast cancer. Although mitosis counting is routinely performed by pathologists, it is a tedious and subjective task with poor reproducibility, particularly among non-experts. Inter- and intraobserver reproducibility of mitosis counting can be improved when a strict protocol is defined and followed. Previous studies have examined only the agreement in terms of the mitotic count or the mitotic activity score. Studies of the observer agreement at the level of individual objects, which can provide more insight into the procedure, have not been performed thus far. METHODS: The development of automatic mitosis detection methods has received large interest in recent years. Automatic image analysis is viewed as a solution for the problem of subjectivity of mitosis counting by pathologists. In this paper we describe the results from an interobserver agreement study between three human observers and an automatic method, and make two unique contributions. For the first time, we present an analysis of the object-level interobserver agreement on mitosis counting. Furthermore, we train an automatic mitosis detection method that is robust with respect to staining appearance variability and compare it with the performance of expert observers on an "external" dataset, i.e. on histopathology images that originate from pathology labs other than the pathology lab that provided the training data for the automatic method. RESULTS: The object-level interobserver study revealed that pathologists often do not agree on individual objects, even if this is not reflected in the mitotic count. The disagreement is larger for objects from smaller size, which suggests that adding a size constraint in the mitosis counting protocol can improve reproducibility. The automatic mitosis detection method can perform mitosis counting in an unbiased way, with substantial agreement with human experts.

Validity of whole slide images for scoring HER2 chromogenic in situ hybridisation in breast cancer.

AIM: Whole slide images (WSIs) have stimulated a paradigm shift from conventional to digital pathology in several applications within pathology. Due to the fact that WSIs have not yet been approved for primary diagnostics, validating their use for different diagnostic purposes is still mandatory. The aim of this study was to test the validity of WSI in assessing human epidermal growth factor receptor 2 (HER2) status in breast cancer specimens using chromogenic in situ hybridisation (CISH). MATERIALS AND METHODS: Ninety-six HER2 CISH slides were scored by two observers on a light microscope (400× viewing magnification) and on WSI (40× scanning magnification, one focus plane) with a minimum of 6 weeks washout period. The concordance between digital and microscopic HER2 scores was assessed. RESULTS: Digitally, 93/96 cases could be assessed (96.8%). Microscopic and digital evaluation of HER2 amplification status were concordant in 68/93 cases ((73.1%, 95% CI: 0.639 -0.823), κ 0.588). CISH underscoring was most noticeable in the amplified and equivocal categories while the highest level concordance was seen in cases with a normal copy number. Additionally there was a noticeable tendency to underestimate the average HER2 scores on WSI: lower in 59 and higher in 11 cases. There was no major difference in time spent for microscopic scoring (86.9 s) and digital scoring (81.7 s). CONCLUSIONS: There was a reasonable concordance between microscopic scoring and WSI-based scoring of HER2 copy number of CISH slides. Nevertheless, WSIs scanned on a single focal plane are insufficient to assess HER2 gene amplification status by scoring CISH due to the noticeable tendency towards digitally underestimating the number of HER2 spots. Scanning at multiple focus planes may offer better resolution for improved digital CISH spot counting.

Improved quality of patient care through routine second review of histopathology specimens prior to multidisciplinary meetings.

AIM: Double reading may be a valuable tool for improving quality of patient care by identifying diagnostic errors before final sign-out, but standard double reading would significantly increase costs of pathology. We assessed the added value of intradepartmental routine double reading of histopathology specimens prior to multidisciplinary meetings. METHODS: Diagnoses, treatment plans and prognoses of patients are often discussed at multidisciplinary meetings. As part of the daily routine, all pathology specimens to be discussed at upcoming multidisciplinary meetings undergo prior intradepartmental double reading. We identified all histopathology specimens from 2013 that underwent such double reading and determined major and minor discordance rates based on clinical relevance between the initial and consensus sign-out diagnoses. RESULTS: We included 6796 histopathology specimens that underwent double reading, representing approximately 8% of all histopathology cases at our institution in 2013. Double reading diagnoses were concordant in 6566 specimens (96.6%). Major and minor discordances were observed in 60 (0.9%) and 170 (2.5%) specimens, respectively. Urology specimens had significantly more discordances than other tissues of origin, Gleason grading of prostate cancer biopsies being the most frequent diagnostic problem. Furthermore, premalignant and malignant cases showed significantly higher discordance rates than the rest. The vast majority (90%) of discordances represented changes within the same diagnostic category (eg, malignant to malignant). CONCLUSIONS: Routine double reading of histopathology specimens prior to multidisciplinary meetings prevents diagnostic errors. It resulted in about 1% discordant diagnoses of potential clinical significance, indicating that second review is worthwhile in terms of patient safety and quality of patient care.

Whole slide images for primary diagnostics of urinary system pathology: a feasibility study.

INTRODUCTION: During the last decade, whole slide images (WSI) have been used in many areas of pathology such as teaching, research, digital archiving, teleconsultation and quality assurance testing. However, WSI have as yet not much been used for upfront diagnostics because of the lack of validation studies. OBJECTIVES: The aim of this study was to test the feasibility of WSI for primary diagnosis of urinary tract pathology. MATERIALS AND METHODS: 100 consecutive urinary tract biopsies and resections which had been diagnosed conventionally between the years 2008-2009 were scanned at 20× magnification, and rediagnosed by two pathologists on WSI, having the original clinical information available, but blinded to the original diagnoses. Original and WSI diagnoses were compared and classified as concordant, slightly discordant (without clinical consequences) and discordant. RESULTS: Original and WSI based rediagnosis were concordant in 87% of the cases. Original and WSI diagnosis were slightly discordant in 8% of cases. Major discrepancies with clinical or prognostic implications were founded in only 5 cases. However, for 6 out of the 13 discrepancies, WSI based diagnoses were considered to be better than the original diagnoses. CONCLUSION: Primary diagnostics of urinary tract specimens can be reliably done on WSI. Further improvements of image resolution may help to increase diagnostic accuracy and WSI acceptance in routine pathology.

Added value of HER-2 amplification testing by multiplex ligation-dependent probe amplification in invasive breast cancer.

BACKGROUND: HER-2 is a prognostic and predictive marker, but as yet no technique is perfectly able to identify patients likely to benefit from HER-2 targeted therapies. We aimed to prospectively assess the added value of first-line co-testing by IHC, and multiplex ligation-dependent probe amplification (MLPA) and chromogenic in situ hybridization (CISH). METHODS: As local validation, HER-2 MLPA and CISH were compared in 99 breast cancers. Next, we reviewed 937 invasive breast cancers, from 4 Dutch pathology laboratories, that were prospectively assessed for HER-2 by IHC and MLPA (and CISH in selected cases). RESULTS: The validation study demonstrated 100% concordance between CISH and MLPA, if both methods were assessable and conclusive (81.8% of cases). Significant variation regarding percentages IHC 0/1+ and 2+ cases was observed between the laboratories (p<0.0001). Overall concordance between IHC and MLPA/CISH was 98.1% (575/586) (Kappa = 0.94). Of the IHC 3+ cases, 6.7% failed to reveal gene amplification, whereas 0.8% of the IHC 0/1+ cases demonstrated gene amplification. Results remained discordant after retrospective review in 3/11 discordant cases. In the remaining 8 cases the original IHC score was incorrect or adapted after repeated IHC staining. CONCLUSIONS: MLPA is a low-cost and quantitative high-throughput technique with near perfect concordance with CISH. The use of MLPA in routinely co-testing all breast cancers may reduce HER-2 testing variation between laboratories, may serve as quality control for IHC, will reveal IHC 0/1+ patients with gene amplification, likely responsive to trastuzumab, and identify IHC 3+ cases without gene amplification that may respond less well.

Whole slide images for primary diagnostics of paediatric pathology specimens: a feasibility study.

INTRODUCTION: Whole slide images (WSI) have been used in many pathology applications such as teleconsultation, teaching and research, but not in primary diagnostics. The aim of this study was to test the feasibility of using WSI in primary diagnostics of paediatric pathology specimens and placental tissue. MATERIALS AND METHODS: Eighty consecutive tissues biopsies and resections from patients under 18 years old were selected, as well as 20 placentas. These cases had been diagnosed in the year 2009 by a single pathologist. The same pathologist who had performed the original diagnosis based on light microscopy was asked to rediagnose these 100 cases on WSI scanned at 20× magnification as well as by light microscopy having the original clinical information available, but blinded to the original light microscopic diagnoses. The original diagnoses were compared with WSI based diagnoses and rediagnoses by light microscopy and classified as concordant, mildly discordant (without clinical consequences) and discordant (with clinical consequences). RESULTS: The original diagnoses were concordant with WSI and light microscopic diagnoses in 90% and 93% of cases respectively, which was not significantly different. Digital reassessment yielded eight mild discrepancies and two discrepant cases (2%) where the difference in diagnoses could have clinical implications for the patient. Light microscopic reassessment showed seven mild discrepancies. It turned out to be difficult to identify nucleated red blood cells on WSI, even when scanned at 40×. CONCLUSIONS: Primary diagnostics of paediatric tissue biopsies and resections can generally well be done on WSI. However, some difficulties were encountered in examining placenta tissue where the identification of nucleated red blood cells may need higher resolution or even scanning at multiple focus depths, which is well possible on most current slide scanners.

Evaluation of mitotic activity index in breast cancer using whole slide digital images.

INTRODUCTION: Mitotic Activity Index (MAI) is an important independent prognostic factor and an integral part of the breast cancer grading system. Thus, correct estimation of this prognostically relevant feature is essential for guiding treatment decision and assessing patient prognosis. The aim of this study was to validate the use of high resolution Whole Slide Images (WSI) in estimating MAI in breast cancer specimens. METHODS: MAI was evaluated in 100 consecutive breast cancer specimens by three observers on two occasions, microscopically and on WSI with a wash out period of 4 months. MAI was also translated to mitotic scores as in grading. Inter- and intra-observer agreement between microscopic and digital MAI counts and scores was measured. RESULTS: Almost perfect inter-observer agreements were obtained from counting MAI using a conventional microscope (intra-class correlation coefficient (ICCC) 0.879) as well as on WSI (ICCC 0.924). K coefficients reflected good inter-observer agreements among observers' microscopic mitotic scores (average kappa 0.642). Comparable results were also observed among digital mitotic scores (average kappa 0.635). There was strong to perfect intra-observer agreements between MAI counts and mitotic scores for the two diagnostic modalities (ICCC 0.716-0.863, kappa 0.506-0.617). There were no significant differences in mitotic scores using both diagnostic modalities. CONCLUSION: Scoring mitoses using WSI in breast cancer seems to be just as reliable and reproducible as when using a microscope. Further development of software and image quality will definitely encourage the use of WSI in routine pathology practice.

Whole slide images as a platform for initial diagnostics in histopathology in a medium-sized routine laboratory.

INTRODUCTION: Whole slide imaging is the process of digitizing glass slides and the creation of Whole Slide Images (WSI), which enable the examination of pathology samples on a computer screen in a manner comparable to light microscopy. WSI have been used for different applications in pathology but their use for primary diagnostics is still limited. Implementing WSI for primary diagnostics would be a turning point necessitating extensive validation to unravel pitfalls and difficulties that could be encountered within the routine workflow. This article is aimed to describe the gradual integration of WSI into routine pathology diagnostics in a medium-sized routine pathology laboratory. METHODS: This project was started with optimizing the digital work environment including the setting up of validation studies, scanning preferences, storing WSI and the implemented adjustments to the workflow for the laboratory and the pathologist. Afterwards scanning glass slides was initiated in the department of pathology at the Atrium Medical Center, Heerlen, The Netherlands, for performing primary diagnostics of breast biopsies. Later this was extended to other specimen types including resections. RESULTS: The validation studies yielded a high concordance rate between WSI and conventional diagnoses. Routine primary WSI based diagnosis was possible in 82.1% of cases. Failure of digital diagnosis was mainly related to poor image quality and logistic problems. CONCLUSION: The quality of the currently produced WSI is sufficient for primary diagnostics in 82.1% of the cases. Improving image quality, adequate retrieval and controlling scanning error will definitely encourage the wide adaptation in routine diagnostics.

Whole slide images for primary diagnostics of gastrointestinal tract pathology: a feasibility study.

During the last decade, whole slide images have been used in many areas of pathology such as teaching, research, digital archiving, teleconsultation, and quality assurance testing. However, whole slide images have as yet not much been used for up-front diagnostics because of the lack of validation studies. The aim of this study was, therefore, to test the feasibility of whole slide images for diagnosis of gastrointestinal tract specimens, one of the largest areas of diagnostic pathology. One hundred gastrointestinal tract biopsies and resections that had been diagnosed using light microscopy 1 year before were rediagnosed on whole slide images scanned at ×20 magnification by 5 pathologists (all reassessing their own cases), having the original clinical information available but blinded to their original light microscopy diagnoses. The original light microscopy and whole slide image-based diagnoses were compared and classified as concordant, slightly discordant (without clinical consequences), and discordant. The diagnoses based on light microscopy and the whole slide image-based rediagnoses were concordant in 95% of the cases. Light microscopy and whole slide image diagnosis in the remaining 5% of cases were slightly discordant, none of these were with clinical or prognostic implications. Up-front histopathologic diagnosis of gastrointestinal biopsies and resections can be done on whole slide images.

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.

Whole slide images for primary diagnostics in dermatopathology: a feasibility study.

BACKGROUND: During the last decade, whole slide images (WSI) have been used in many areas of pathology such as teaching, research, digital archiving, teleconsultation and quality assurance testing. However, WSI have not regularly been used for routine diagnosis, because of the lack of validation studies. AIM: To test the validity of using WSI for primary diagnosis of skin diseases. MATERIALS AND METHODS: 100 skin biopsies and resections which had been diagnosed light microscopically one year previously were scanned at 20× magnification, and rediagnosed by six pathologists (every pathologist assessed his own cases), having the original clinical information available, but blinded to the original diagnoses. The WSI diagnoses were compared to the initial light microscopy diagnosis and classified as concordant, slightly discordant (without clinical consequences) or discordant. RESULTS: The light microscopy and the WSI based diagnosis were concordant in 94% of the cases. The light microscopy and WSI diagnosis were slightly discordant in 6% of the cases. For one of the slightly discrepant cases the WSI diagnosis was considered better, while the original diagnosis was preferred for the other five cases. There were no discordant cases with clinical or prognostic implications. CONCLUSION: Primary histopathological diagnosis of skin biopsies and resections can be done digitally using WSI.