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Pathology Leaders is a scientific and educational portal that offers topics concerning histology, ranging from the basics to specific application know-how. It is dedicated to be a lively, constantly developing science portal containing high-quality content, regularly publishing new and interesting articles, applications and tutorials, and having a steadily growing community of participating authors and experts.

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New Diagnostic Modalities in Refining Diagnoses in Haematological Malignancies


Latest Articles

Varying the approach angle in stereotaxic surgery can overcome the conflict between positional accuracy and interpretability. Fortunatly modern computer controlled stereotaxic instrumets make this possible. Read article

A discussion on the techniques used for removing mineral from bone, or other calcified tissue, so that high-quality paraffin sections can be prepared. Read article

Wilms’ Tumour (WT) is a tumour of the kidneys that typically occurs in children. WT1 protein expression in mesothelial cells has become a reliable marker for the diagnosis of mesotheliomas. The NCL-L-WT1-562 (WT49) was found to be very specific and best suited to this facility’s fully automated Immunohistochemistry (IHC) laboratory, when compared with the WT1 6F-H2 clone. The positive reaction of WT49 was restricted to nuclear staining without cytoplasmic staining which has been described in other WT1 antibodies. Read article

The DOG-1 antibody can potentially diagnose approximately 13% more GIST’s on IHC than CD117 staining. It is a sensitive and specific marker for GIST, warranting further investigation for the inclusion of this marker as an adjuvant to the panel of antibodies for the accurate identification and diagnosis of GIST. Read article

Fixation is a critical step in the preparation of histological sections. If it is not carried out under optimal conditions or if fixation is delayed, a tissue specimen can be irreversibly damaged. No matter how much care is subsequently taken in tissue processing, microtomy and staining, the morphological and histochemical information obtainable from the specimen will be compromised. This series of five articles explains the theory behind fixation and the practical use of common, emerging and specialized fixitives. Read article

This second part of the Fixation and Fixatives series covers the factors that influence the rate and effectiveness of tissue fixation as well as looking at two common fixatives: formaldehyde (histology) and glutaraldehyde (ultrastructural electron microscopy studies). Read article

As well as formaldehyde and glutaraldehyde, discussed previously, a number of other reagents have been used for fixation, sometimes in simple solution but often combined with other agents in the form of compound fixatives. The more important of these are discussed here in Part 3 of the Fixation and Fixatives series. Read article

In this fourth part of the Fixation and Fixatives series, we look at some of the many popular and traditional fixative solutions that have been used in histology for the last 100 years. This part also has an overview of proprietary solutions and provides advice on how to select the right fixative for your application. Read article

In this final part of the Fixation and Fixatives series we look at practical ways to optimise fixation quality, discuss how heat effects fixation and finish with an introduction to the relatively new field of microwave fixation. Read article

Join Clifford M. Chapman, MS, HTL(ASCP), QIHC, technical director, Strata Pathology Services Inc., Lexington, MA, on April 26 from 2-3 p.m. for a free webinar on quality management for the histology laboratory. Read article

The hematoxylin and eosin stain (H&E) is the most widely used stain in histology and histopathology laboratories. When it is properly performed it has the ability to demonstrate a wide range of normal and abnormal cell and tissue components and yet it is a relatively simple stain to carry out on paraffin or frozen sections. In histopathology a high proportion of cases can be diagnosed by an experienced pathologist using an H&E stain alone. Read article

Neuroscience research very frequently requires animal sacrifice and microscopic examination of the brain. Certainly, stereotaxic surgery is always followed by histological examination, if only to confirm the correct placement of the probe. Read article

Neuroscience researchers usually need to see slices of whole brain in order to determine the location in brain of detail they are viewing under the microscope. The brain needs to be hardened to allow cutting the thin slices, unless a vibrating blade microtome, which is much slower, is used. Read article

Laboratories continue to feel pressure from growing volumes, resource constraints and shorter turnaround times, while also needing to maintain or improve quality. The goal of the laboratory is to improve patient care by delivering the highest quality slides to the pathologist in the shortest amount of time. Read article

From time to time, in all histopathology laboratories, paraffin blocks will be encountered that are difficult or even impossible to section. This publication provides guidance on how to deal with these difficult blocks to get the best possible section, and how to identify and avoid a repeat of underlying causes. Read article

In October 2008, Leica Microsystems worked with Catholic Medical Center in Manchester, New Hampshire to design and set-up a Lean laboratory. Read article

This tutorial illustrates the basic steps needed to create the immunohistochemistry (IHC) stains used in diagnosis of tissue-based disease. Read article

Sample tracking systems help reduce misdiagnosis by positively identifying patient tissue throughout the diagnostic process. Read article

Routine (or H&E) and special stains allow us to visualise otherwise transparent tissue under a microscope and are critical for tissue-based diagnosis. Read article

An introduction to the preparation of specimens for microscopy in the histopathology laboratory. Read article

Anyone who has visited Dr. Peter’s website tutorial on frozen section techniques knows that he is a true believer in the brush technique. Let’s learn how he teaches this valuable skill to his resident. Read article

Microscopic analysis of cells and tissues requires the preparation of very thin, high quality sections (slices) mounted on glass slides and appropriately stained to demonstrate normal and abnormal structures. Most fresh tissue is very delicate and easily distorted and damaged and it is thus impossible to prepare thin sections from it unless it is chemically preserved or “fixed”, and supported in some way whilst it is being cut. Read article

Staining protocols utilizing hematoxylin are the most commonly used of the routine staining procedures performed in the histology laboratory. This article is a review of the current state of understanding of the chemistry of aluminum based hematoxylin stains and the mechanism by which these stains act. Read article

Tumor hypoxia is a common phenomenon in some subtypes of renal cell carcinomas (RCC) and may play a role in their biology and response to treatment. Here we evaluate a novel hypoxia marker HIG2 in renal cortical tumors and normal tissues. Read article

This article describes a system used for embedding of tissues for the preparation of frozen sections. This novel system uses simple techniques and apparatus to accomplish face-down embedding in freezing-temperature steel wells. The system is easy to learn and offers many advantages over conventional methods, including speed, high precision and predictability, and reduced tissue wastage. Read article

The value of immunohistochemistry (IHC) is due to the power of the procedure to recognize and localize specific proteins (markers) within a tissue specimen. By determining the presence or absence of specific markers within a tumor the pathologist is provided with clues that may be helpful in accurately classifying or identifying the neoplasm. Read article

To prepare biological tissue for observation under a microscope, the tissue is usually cut in thin slices. Most biological tissue is too soft to cut; the knife would push into it and compress it, even if the cutting edge was very sharp. Therefore, the tissue is either frozen and sectioned in a cryostat or embedded in a hardening material like paraffi n or resin, or cut while still soft with a vibrating blade microtome. The correct knife angle is the subject of much misunderstanding, misleading experience, and incorrect information passed between microtomists, but in fact can be logically derived. Read article

By understanding and adopting lean principles, laboratories can achieve more efficient workflows by eliminating steps, reducing waste, and producing higher quality slides more quickly than ever before. Read article

Stereotaxic Accuracy

02. Nov 2010

Together with a suitable manipulator and oriented head holder, brain maps can be used to position probes at a preplanned site in the brains of several rodents. The instrument for moving a probe to a given coordinate in space – inside the brain – is a stereotaxic instrument. Read article

Folate Receptor-alpha (FR-alpha) has been described extensively in many tumour and tissue types. Up to now the majority of this work has been looking at mRNA with some limited immunohistochemistry restricted to frozen tissue. In this article we review the extensive testing undertaken to evaluate a novel mouse monoclonal antibody to FR-alpha that works in formalin-fixed paraffin-embedded tissue. Read article

Three dimensional reconstruction of liver tissue is beneficial as it can improve understanding of the normal architecture of the vascular and biliary system; additionally, awareness of how these systems are affected by various pathological processes may help to inform future treatment choices. Read article

A subset of renal cortical tumors cannot be accurately classified based on their morphologic features owing to partial overlap in their histologic appearance. Read article

CD99 is a transmembrane glycoprotein which is expressed in a wide range of tissues. Although its function is not fully understood it has been implicated in a variety of cellular processes including the homotypic aggregation of the T cells, apoptosis of immature thymocytes, up-regulation of T cell receptor and MHC molecules and leukocyte diapedesis. Read article

The North East Haematopathology Diagnostic Service, based at the Royal Victoria Infirmary in Newcastle upon Tyne, provides a regional service for expert assessment of lymphoproliferative and myeloproliferative disorders for a regional network of 14 NHS hospitals in the North East and Cumbria. Read article

Creating great paraffin sections using a rotary microtome takes a great deal of skill and experience. Microtomy and Paraffin Section Preparation is a great training aid for new microtomists and is an excellent refresher for experienced operators. Read article

Special stains that are used for the evaluation of mucins, mucin-like molecules and other carbohydrate containing macromolecules remain in demand and are utilized frequently in the histology laboratory. This article is intended as a basic review of the mechanisms of action of the most commonly used mucin special stains including alcian blue, mucicarmine, colloidal iron and the periodic acid Schiff technique. Read article

The increased sensitivity of immunohistochemistry (IHC) over standard Hematoxylin and Eosin (H&E) staining has established the IHC technique in the study of many diseases. Herein we describe the utility of some NovocastraTM antibodies that can be used in the study of brain and muscle diseases. Read article

Dr. George Paxinos paved the way for future neuroscience research by being the first to produce an accurate 3D stereotaxic atlas to guide placement of electrodes and injections in the brain of experimental animals. His atlases are now international standards. Read article

Lean – everybody has heard of it and we would all like to have the claimed productivity benefits, but does it work for real-world ­histopathology? Johnathon Deniz, Automation Product Manager at Leica Microsystems, takes Lean out of the text books and into the histology laboratory to show that Lean Histology™ does offer great potential to laboratories, pathologists and patients. Read article

Double immunoenzymatic staining is a widely used technique to directly analyse the expression of multiple molecules in a single tissue section. One of the aims of our work was to explore the capability of an automated staining system to perform multiple labeling. Read article

One of the first uses of formaldehyde as a fixative for tissue specimens was accidentally discovered by a Dr. F. Blum towards the end of the nineteenth century. Based on Blum’s observations a 4% solution has remained the percentage recommended for formaldehyde fixation and has not been challenged despite the well documented detrimental effects formalin fixation has on tissue immunoreactivity! Read article


01. Oct 2008

CD11c is an integrin glycoprotein expressed by mononocytes and macrophages, neutrophils, myeloid dendritic cells and a small subset of lymphocytes. Although antibodies to CD11c have been available since the mid-1980s, the new antibody 5D11 is the first to recognise a formalin-resistant epitope. Read article

Unique to Creutzfeldt-Jakob disease (CJD) is the accumulation of an abnormal protein in the central nervous system (CNS) known as prion protein (PrPSC). Immunocytochemistry is essential for the demonstration of PrPSC along with rigorous pretreatments to ensure that normal PrPC is destroyed and only PrPSC is demonstrated. Read article

CD33 Antigen Detection by PWS44 a New Monoclonal Antibody Reactive in Paraffin Tissues Sections: Pattern of Reactivity and Potential Diagnostic Utility. Read article

Epstein-Barr virus (EBV) is a ubiquitous herpesvirus that infects and establishes persistent infection in a host. Latent EBV infection has been linked to a wide range of benign and malignant lesions. This study compares the sensitivity of automated IHC and ISH staining to detect latent EBV infection. Read article

From patient to pathologist, preparing tissue specimens for histological examination requires care, skill and sound procedures. This straightforward guide to good histology practice provides practical advice on best-practice techniques and simple ways to avoid common errors. Read article

Newcastle upon Tyne – this lively town in Northern England is not only famous for its culture, but it has been the base for the developer and manufacturer of antibodies and other reagents of the brand, Novocastra™. “Novocastra” is based upon the Latin name for the city of Newcastle and was the name given to the original company founded by Prof C. Wilson Horne. The company... Read article

Histology artifacts and cytology artifacts are structures that were not originally present in the living tissue. These artifacts can be from a range of sources including contamination, poor tissue preparation and surgical procedures. Understanding artifacts is important for both histologists and pathologists as they have the potential to compromise accurate diagnosis. Read article

CD3 is a reliable and specific marker for the detection of cells of the T-cell lineage and has been, therefore, routinely used by pathologists for many years. The PS1 clone was a great advancement when it was first released. It was robust and able to work in decalcified bone marrow trephines where only the rabbit polyclonal antibody had been previously effective. Read article

We at UCL Advanced Diagnostics were lucky enough to be involved in the external assessment of CD3, LN10 in its validation stage. This enabled us to begin using it routinely as soon as it was commercially available, indicating our feelings on it! Read article

FXIIIa is a blood and intracellularly produced coagulation factor, which is widely expressed in variety of cell types. It is believed to be vital in the final stages of the clotting cascade and is also important in wound healing and repair mechanisms. It also has a role in angiogenesis in embryo implantation. Read article

Multiple myeloma is the second most frequent B-cell malignancy in Western countries. Current guidelines suggest that light chain clonality needs to be demonstrated to confirm diagnosis of multiple myeloma. Immunohistochemistry of kappa and lambda light chains can often give difficulties in interpretation, especially in cases of recurrent or residual myeloma. In-situ hybridisation techniques have gone some way to solve these problems. Read article

For most aspects of cell characterisation in haematopathology, histology combined with immunohistochemistry (IHC) provides the current gold-standard. Despite more than 20 years of continuous advancement in antigen retrieval and new reagents for IHC, it remains the case that detection of immunoglobulin light and heavy chains by this means is difficult for many laboratories to achieve to a satisfactory standard. Read article

Xylene-free processing (XFP) was evaluated over several months using the Leica Microsystems PelorisTM tissue processor. The criteria selected pre evaluation were processed block quality, microtomy properties, stained section quality, duration of processing, running costs, user-friendliness and reliability. Read article

The bcl-6 gene is associated with translocations affecting 3q27 in cases of diffuse large B-cell lymphoma (DLBCL). The gene product is a zinc finger protein thought to be involved in control of germinal centre proliferation. Bcl-6 protein can be detected immunohistochemically and positive staining is nuclear in location. Read article

Detection of CD33 using monoclonal antibodies has been critical in immunophenotyping acute leukemias, particularly acute myeloid leukemias. To date this has only been possible by either flow cytometry or by frozen section immunohistochemistry. Now the first CD33 antibody... Read article

Chemical disinfectants are not only toxic for the user but are also awkward to use and dispose of. Leica Microsystems has therefore developed cryostats with UVC disinfection to enhance safety and efficiency when cutting cryosections. The method is simple to use and requires no warming of the cryo-chamber. To prove the efficiency... Read article