STP Specialisms | Histopathology

Hi everyone, my name is Alix, or you might me know as @happyhistologist. I am a HCPC registered Biomedical Scientist and second year STP trainee specialising in Histopathology. But what actually is histopathology?! Breaking down the word into two smaller words can help to understand its true meaning. ‘Histo’ means tissue and ‘pathology‘ is the investigation of disease, therefore histopathology is the investigation of disease in tissue.

The histopathology laboratories are typically located in the pathology department of the hospital. It is unlikely that you will ever come across the laboratories as they are often hidden away out of the view of patients. However, it is likely that you will require the histopathology services at some stage of your life!

An example of a histology laboratory. This is a photo of the histology laboratory at Blackpool Victoria Hospital where I completed my Biomedical Scientist training.

Uses of Histopathology in Healthcare

Have you ever had a suspicious mole removed from your skin? Or perhaps you have had colonoscopy investigations where biopsies were taken from your colon? How about having your tonsils taken out when you were little? Or your appendix out after a bout of appendicitis?  Well if the answer to any of these questions is yes, then you will have been involved in histopathology investigations.

The histology department investigate tissue samples from any site of the human body to provide a diagnosis, which is responsible for the patient’s disease symptoms. Therefore, the types of samples that we receive in the histology department are extremely varied ranging from tiny biopsies to entire organs. It is advisable that you have a strong stomach if you are going to work in a histology laboratory as you are likely to see some gruesome sights, for an example, Google: “Teratoma”, go on, I dare you!

Histopathology and Cancer

Histopathology investigations are critical to the management of chronic diseases such as cancer. To provide some context for histopathology involvement in cancer treatment, let’s consider the whole patient pathway:

A patient presents to their GP with symptoms such as a lump, changes of bowel habit or a persistent cough. The GP will refer the patient for further investigations typically involving scans but also a biopsy. Biopsies are tiny pieces of tissue taken from the diseased area with the aim of identifying the cellular changes that are responsible for the patient’s symptoms. Typically, biopsies are less than 3mm in size and it is our role in the histopathology department to process the biopsy in the most appropriate way so that a Consultant Histopathologist can analyse the individual cells using a microscope to make a diagnosis.

Colon biopsies obtained from endoscopy (Pita et al, 2017)
Microscopic appearance of colon biopsy after histological processing (Moore et al, 2020)

Once a formal diagnosis has been made, the Consultant will report their findings at a multidisciplinary team meeting for clinicopathological correlation to enable an appropriate management plan to be formulated for the patient. This may involve additional surgery for example a large excision or removal of an entire organ! Again, this specimen will be sent directly to the histopathology laboratory for further investigation and a final diagnosis. Below is a comparison two histology specimens under the microscope, one is health and one is cancerous, can you spot the differences between the two images?

Histology of normal skin. Each of the layers of the skin are clearly demonstrated as well as the underlying tissue (Ji and Li, 2016).
Histology of a basal cell carcinoma (skin cancer). There are distinct microscopic features that can be used to distinguish between normal skin and cancerous skin. For example, the skin cancer has nests of tumour cells demonstrated by the purple structures in the underlying tissue (Wollina, 2009).

More recently, histopathology specimens have not only been used for diagnostic purposes. Tumour cells are now being investigated using molecular pathology techniques to predict patient response to cancer treatment. Using a combination of histological and genetic tests, we can now identify specific mutations in the tumour which can be targeted with modern cancer therapies.

The Histopathology Workforce

Now that you have been introduced to the discipline of histopathology, you may be wondering ‘what do histopathology Clinical Scientists do in their day to day work?!’ Well, the answer is not as straightforward as you may expect. Conventional histopathology laboratories have largely been run by Biomedical Scientists alongside Medical Laboratory Assistants and Consultant Histopathologists. A Biomedical Scientist is a HCPC registered profession that has well-established training programmes and routes of progression governed by the Institute of Biomedical Science. The idea of Clinical Scientists working in histopathology is a relatively new concept and unfortunately it has been met with some resistance.

Conventionally, Biomedical Scientists were responsible for laboratory processing of tissue specimens and Consultant Histopathologists were responsible for dissection of tissue specimens, writing diagnostic reports and post mortem examinations. However, with the impending shortage of histopathology Consultants, the workforce has had to adapt to future-proof the service. As a result, Biomedical Scientists are now able to undertake specialist training courses that will lead to qualifications in specimen dissection and histopathology reporting.

So where does this leave the Clinical Scientist? The current STP curriculum has been designed to place a histopathology STP student somewhere between a Biomedical Scientist and a Consultant Histopathologist. The curriculum includes training in dissection of specimens from a whole range of organ groups as well as an introduction to histopathology reporting. Some training centres see this as a viable training approach whereas others prefer to focus on the specimen processing techniques akin to the role of a Specialist Biomedical Scientist.

I realise at this point that I have still not answered the question: ‘what does a Clinical Scientist in Histopathology actually do?!’ And to this there is no clear answer. It largely depends on the interests of the individual and the specialist areas within histopathology that they wish to pursue after graduating from the STP. Previous histopathology graduates have gone into a wide range of careers including specimen dissection, histopathology reporting, quality management, molecular pathology or laboratory management roles.

Roles of a Histopathology Trainee

Personally, my training is very similar to that of a Specialist Biomedical Scientist with the addition of a part-time MSc and first year rotations in genetics, cytology and andrology. An average day largely involves preparing the tissue specimens for microscopic analysis. Daily responsibilities include receiving specimens, assisting with dissection of specimens, tissue processing, embedding and orientating tissue specimens, microtomy and finally tissue staining techniques. I am also involved in specialist diagnostic techniques such as ‘special stains’, immunohistochemistry and molecular testing.

This is a microtome, an essential piece of equipment for histological investigations. A microtome is used to cut fine sections of tissue (approximately 4μm thickness) which are then placed onto a glass microscope slide.
The cells in the tissue section would appear colourless under the microscope at this stage (Lisowski, 2019). The tissue must be stained to allow cells and tissue structures to be microscopically evaluated for a diagnosis. Routinely, tissue sections are stained with haematoxylin and eosin but special stains and immunohistochemical stains can be used to demonstrate specific biomarkers, structures and organisms in the tissue.
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An example of a special stain used to demonstrate fungal spores in a tissue sample (Roche Diagnostics, 2021)
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An example of immunohistochemistry used to distinguish between different lung cancers (Roche Diagnostics, 2021)

By the end of my STP training, I will be trained in specialist areas including dissection of gall bladders and appendix, rapid on-site evaluation at head and neck clinics, MOHS frozen sectioning for skin cancer clinics and finally overseeing the everyday running of the laboratory. Upon programme completion, I will be eligible to apply for Senior Biomedical Scientist positions or pursue further qualifications in tissue dissection and histological reporting. I’m not quite sure what I would like to specialise in yet but I can definitely say that I have learnt a lot during my STP experience so far! Here are some photos from the first 18 months of my journey :

Scrubs and clogs for my andrology rotation
2019 STP cohort for Cellular Sciences – final day of first year Uni!
Anatomy cupcakes for Biomedical Science Day
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Outreach at a local school on Healthcare Science Week

When I applied for the STP, I was acutely unaware of the conflict surrounding the role of histopathology Clinical Scientists. And without realising, I was part of the final cohort of histopathology trainees to embark on the current curriculum. A new curriculum has now been designed for the histopathology STP with a refined approach to dissection training and added focus on molecular and digital pathology.  The new curriculum is still being finalised so is not due to be rolled out for its first intake until 2022.  As a result, there are no histopathology places available for the 2021 STP intake but if you can wait until next year, the new programme promises to offer some very exciting opportunities!

References:

Ji, H. and Li, X.-K. (2016) ‘Oxidative Stress in Atopic Dermatitis.’ Hindawi Publishing Corporation, 2016 pp. 1-8.

Lisowski, A. (2019) Science of H&ELeica Biosystems. Available at: https://www.leicabiosystems.com/knowledge-pathway/science-of-he/ (Accessed: 13 February 2021).

Lung cancer IHC portfolio (2021). Available at: https://diagnostics.roche.com/global/en/products/tests/lung-cancer-ihc-ish-portfolio.html (Accessed: 13 February 2021).

Moore, M., Feakins, R. and Lauwers, G. (2020) “Non-neoplastic colorectal disease biopsies: evaluation and differential diagnosis”, Journal of Clinical Pathology, 73(12), pp. 783-792. doi: 10.1136/jclinpath-2020-206794.

Pita, I., Bastos, P. and Dinis-Ribeiro, M. (2017) ‘Mistakes in tissue acquisition during endoscopy and how to avoid them.’ United European Gastroenterology Education, 17 pp. 45-47.

VENTANA BenchMark Special Stains system (2021). Available at: https://diagnostics.roche.com/us/en/products/systems/ventana-benchmark-special-stains-system.html (Accessed: 13 February 2021)

Wollina, U. (2009) ‘Addiction to Tanning – A New Cause of Early Onset of Nonmelanoma Skin Cancer.’ The Open Dermatology Journal, 3 pp. 86-88.

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